details of PLATON tests


PLAT002 Type_2 Report number of atom sites with distance/angle restraints
 This ALERT reports the number of atomic sites that are flagged as distance 
 or angle restrained (D-Flag)   

PLAT003 Type_2 Report number of non-H atoms with Uiso or Uij restraints
 This ALERT reports the number of non-H atoms that are flagged as handled   
 with Uiso or Uij restraints (U-Flag)   

PLAT004 Type_5 Report Dimensionality of polymer
 This ALERT reports on polymeric networks and their dimensionality as found in  
 the crystal structure. 
 Note: Polymeric structures can be legitimate or due to an erroneous
 structure analysis.

PLAT005 Type_5 Check for refinement instruction file
 No embedded 'refinement details' records were found in the CIF. Acta Cryst.
 requires the inclusion of the last shelxl.res file (in case of a SHELXL or 
 XL refinement or similar for non-SHELXL refinement programs) in the CIF,   
 embedded between records with semicolons in position 1, preceded   
 by an '_iucr_refine_instructions_details' record.  
 Note: SHELXL20xy will automatically include the final .res as an embedded  
 comment with the dataname '_shelx_res_file'.   

PLAT006 Type_5 Check for Extinction parameter refinement
 This ALERT reports the refinement of an extinction parameter.  
 SHELXL corrects Fobs values in the FCF for Extinction. JANA not.   

PLAT007 Type_5 Report on unrefined D-H atoms
 It is standard practice to refine Hydrogen atoms on hetero atoms as
 proof of their correct assignment. 

PLAT011 Type_1 Test for any ATOMS found in CIF
 No atom coordinates were detected in the CIF prior to the U(i,j) loop. 

PLAT012 Type_1 Check for valid _shelx_res_checksum
 The supplied CIF contains a '_shelx_res_file' record but not a valid   
 associated '_shelx_res_checksum' record. A valid pair of embedded .res and 
 .hkl files allows the automatic creation of a .fcf file with SHELXL20xy to be  
 used for a detailed analysis of the refinement result. A file is valid when
 the calculated and reported checksums are identical. Only characters with an   
 ASCII value higher than 32 contribute to the checksum. 
 An embedded .res file might be broken, either due to tranfer errors or to  
 deliberate or accidental post-refinement editing of its content.   

PLAT013 Type_1 Check for _shelx_hkl_checksum
 The supplied CIF contains a '_shelx_hkl_file' record but not a valid   
 associated '_shelx_hkl_checksum' record. A valid pair of embedded .res and 
 .hkl files allows the automatic creation of a .fcf file with SHELXL20xy to be  
 used for a detailed analysis of the refinement result. A file is valid when
 the calculated and reported checksums are identical. Only characters with an   
 ASCII value higher than 32 contribute to the checksum. 
 An embedded .res file might be broken, either due to tranfer errors or to  
 deliberate or accidental post-refinement editing of its content.   

PLAT014 Type_1 Check for _shelxl_fab_checksum
 The supplied CIF contains a '_shelx_fab_file' record but not a valid   
 associated '_shelx_fab_checksum' record. A valid pair of embedded .res and 
 .hkl files allows the automatic creation of a .fcf file with SHELXL20xy to be  
 used for a detailed analysis of the refinement result. A file is valid when
 the calculated and reported checksums are identical. Only characters with an   
 ASCII value higher than 32 contribute to the checksum. 
 An embedded .res file might be broken, either due to tranfer errors or to  
 deliberate or accidental post-refinement editing of its content.   

PLAT016 Type_5 Check for refinement FAB file (SHELXL20xy)
 No embedded .fab record was found in the CIF file that was created with
 SHELXL20xy (or XL). SHELXL20xy automatically includes the '.fab' file that 
 was used in the refinement (along with the final '.res' & '.hkl' files) as 
 an embedded comment with the dataname '_shelx_fab_file'. Do not change this
 dataname. Such a record is useful for archival and follow-up calculations. 

PLAT017 Type_1 Check the Consistency of Scattering Type
 Check for the correct scattering type assignment to this atom. 

PLAT018 Type_1 Check _diffrn_measured_fraction_theta_max and full identical
 The reported value of _diffrn_measured_fraction_theta_full is not equal to 
 the reported value of _diffrn_measured_fraction_theta_max with 
 _diffrn_reflns_theta_max and _diffrn_reflns_theta_full reported as equal.  

PLAT019 Type_1 Check _diffrn_measured_fraction_theta_max/full consistency
 The reported value of _diffrn_measured_fraction_theta_full is less than
 the reported value of _diffrn_measured_fraction_theta_max. Their ratio is  
 reported when less than 1.0. When theta_full is less than theta_max such   
 a value indicates that there are relatively more reflections missing at
 lower resolution.  
 This ALERT can easily be addressed by updating the reported '*_full' values
 with the corresponding '*_max' values in the CIF.  

PLAT020 Type_3 Check Rint
 The value of Rint (i.e. _diffrn_reflns_av_R_equivalents) should normally be
 considerably less than 0.12 and in the order of magnitude of the reported  
 R-values. Rint may be relatively meaningless when based on a very limited  
 number of averaged data. Higher values should be accompanied by a suitable 
 explanation in the _publ_section_exptl_refinement section. However,
 authors should first ensure that there are not overlooked problems 
 associated with the data or the space-group. Elevated values for   
 _diffrn_reflns_av_R_equivalents may be indicative of a need to recollect   
 the data from a crystal of higher quality or that there is a problem with  
 the data treatment. Consider the following
 (a) The absorption corrections are inadequate or inappropriate.
 (b) The overall quality of the data may be poor due to the crystal quality.
 (c) The crystal is very weakly diffracting, so that a large proportion of  
     essentially "unobserved" reflections are being used in the refinement. 
     You should consider using a better crystal or a data collection at 
     low temperature and/or, if the compound is organic, using Cu radiation.
 (d) You are working in the wrong crystal system or Laue group. 
 (e) You have only a very small number of equivalent reflections, which 
     may lead to artificially high values of _diffrn_reflns_av_R_equivalents
 Note that if _diffrn_reflns_av_sigmaI/netI is also large, the quality  
 of the data should be considered to be suspect.

PLAT021 Type_4 Check Expected number of Reflections (Max = 1 Centro, 2 - non-centro)
 The expected number of reflections corresponds to that in the asymmetric   
 unit of the Laue group. Expected ratio: less-or-equal 1 for centro symmetric   
 structures and less than 2 for non-centrosymmetric structures. 
 Reasons to exceed those numbers can be:
  1 - Systematic absencies not omitted from the observed data count.  
  2 - Refinement with redundant (i.e. not merged/unique) data set.  
  3 - SHELXL HKLF 5 Refinement  

PLAT022 Type_3 Check Expected number of Reflections (completeness)
 Test for data completeness. The ratio of the reported number of unique 
 reflections and expected number of reflections for the resolution given is 
 reported. The ratio can be low due to a missing cusp of data when collected
 with a 2D-detector. Alternatively, the wrong asymmetric part of reciprocal 
 space was collected on a serial detector system.   

PLAT023 Type_3 Check Theta-Max
 Check resolution of the data set. Alert is issued when sin(theta)/lambda < 0.6 

PLAT024 Type_4 Check for required Friedel pair averaging Z<=Si (Obsolete 1/1/2011)
 (No longer imposed)

PLAT025 Type_1 Check for Hmin..Lmax
 Check reported h,k,l - range with calculated range based on reported theta-max.

PLAT026 Type_3 Check for a weak data set
 Check whether a sufficient fraction of the unique data set is indeed above the 
 2 * sigma(I) level.
 All reflection data are included in this test. Check whether this low ratio
 is caused by weak data beyond sin(theta)/lambda > 0.5 (i.e. low resolution).   

PLAT027 Type_3 Check _diffrn_reflns_theta_full
 Ideally (and a requirement for publication in Acta Crystallographica), 
 the dataset should be essentially complete, as defined by  
 -diffrn-measured-fraction-theta-full (close to 1.0), up to 
 sin(theta)/lambda = 0.6 (i.e. 25.24 degrees MoKa). 
 The three major causes of incomplete data sets are:
 1 - A missing cusp of data due to data collection by rotation around   
     the spindle axis only (standard on some image-plate systems).  
     Cure: collect an additional data set after remounting the crystal. 
 2 - The DENZO image processing package has problems with certain strong
     reflections. They are often excluded from the data set.
     Cure: Add an additional scan at lower power setting in order to
     include strong low order reflections.  
 3 - Incomplete scans.  

PLAT028 Type_3 Check the reported _diffrn_measured_fraction_theta_max
 Ideally, the reported '_diffrn_measured_fraction_theta_max' value, 
 corresponding to theta-max, should be close to 1.0.

PLAT029 Type_3 Check the reported _diffrn_measured_fraction_theta_full
 Ideally (and a requirement for publication in Acta Crystallographica), 
 this fraction should be close to 1.0 for theta-full greater or equal   
 to sin(theta/lambda) = 0.6 (i.e. 25.24 degrees for MoKa and 67.7 degrees   
 for CuKa  radiation).  
 The three major causes of incomplete data sets are:
 1 - A missing cusp of data due to data collection by rotation around   
     the spindle axis only (standard on some image-plate systems).  
     Cure: collect an additional data set after remounting the crystal. 
 2 - The DENZO imageprocessing package has problems with certain strong 
     reflections. They are often excluded from the data set.
     Cure: Add an additional scan at lower power setting in order to
     include strong low order reflections.  
 3 - Incomplete scans, possibly based on erroneously assumed higher than
     actual symmetry.   
 Note: The default value of _diffrn_measured_fraction_theta_full that   
 is automatically calculated and inserted in the CIF by SHELXL-97 might 
 generate A-level ALERTS when significant numbers of reflections are
 missing at higher theta values. In order to avoid such an ALERT,   
 substitute the values calculated with the SHELXL instruction 'ACTA 50' 
 for _diffrn_reflns_theta_full and _diffrn_measured_fraction_theta_full 
 respectively. For Mo-radiation, corresponding values of 25 degees (or  
 higher) and 0.99 (or higher) are expected. (See SHELXL manual).
 PLATON may be used to analyse the case at hand (by invoking either the 
 'FCF-VALIDATION' mode or the 'ASYM-VIEW' mode).

PLAT030 Type_1 Check _diffrn_reflns_number >= reflns_number_total
 The number of measured reflections should be equal or greater than the 
 number of unique reflections.  

PLAT031 Type_4 Check need for Extinction Correction Parameter
 This test checks whether a refined extinction parameter is meaningful  
 i.e. whether its value is significantly larger than its corresponding s.u. 
 If not, this parameter should be removed from the model and the structure  
 refined without this meaningless additional parameter. 
 The current default gives a warning when its value is within 3.33 s.u. 
 SHELXL97-2 will not allow negative values leading to ill-convergence and   
 non-zero maximum shift/error values: remove extinction parameter from the  
 refinement.

PLAT032 Type_4 Check s.u. Flack Parameter
 Check the validity of the absolute structure determination.
 A high s.u. indicates that the experimental data do not support the
 determination of the absolute structure. This will generally be the case   
 with light atom MoKa data where f" is nearly zero. 
 Note: Use the TWIN & BASF 0.0 instructions in SHELXL97. The default
 FLACK parameter is not always reliable, in particular when strongly
 correlated with the position of the origin (e.g. along y in space-group P21).  
 Please refer to Flack,H.D. & Bernardinelli, G. (1999) Acta Cryst. A55, 
 908-915 and (2000) J. Appl. Cryst., 33, 1143-1148. 

PLAT033 Type_4 Check Flack Parameter value
 Check the relevance/validity of the absolute structure determination.  
 Please refer to Flack,H.D. & Bernardinelli, G. (1999) Acta Cryst. A55, 
 908-915 and (2000) J. Appl. Cryst., 33, 1143-1148. 
 A value of the Flack parameter that deviates significantly from zero   
 (taking into account the associated s.u.) might indicate that the  
 absolute structure should be inverted in case of a value closer to 1.0 
 than to zero. A value close to 0.5 may be indicative of an inversion   
 twin or a missed centre of inversion.  
 For valid absolute structure assignments, abs(x) should be less than   
 2 * s.u., with s.u. < 0.04. For enantiopure compounds, s.u. should be less 
 than 0.1.  

PLAT034 Type_1 Check for Flack parameter value specified Z>Si, non-centro
 No Flack parameter value given for non-centrosymmetric structure with  
 heaviest atom Z > Si. This might be intentional.   

PLAT035 Type_1 Check for _chemical_absolute_configuration
 Options are 'rm', 'ad', 'rmad', 'syn', 'unk' or '.'
 rm   : absolute configuration established by the structure determination   
        of a compound containing a chiral reference molecule of known   
        absolute configuration. 
 ad   : absolute configuration established by anomalous dispersion effects  
        in diffraction measurements on the crystal. 
 rmad : absolute configuration established by the structure determination   
        of a compound containing a chiral reference molecule of known   
        absolute configuration and confirmed by anomalous dispersion
        effects in diffraction measurements on the crystal. 
 syn  : absolute configuration has not been established by anomalous
        dispersion effects in diffraction measurements on the crystal.  
        The enantiomer has been assigned by reference to an unchanging  
        chiral centre in the synthetic procedure.   
 unk  : absolute configuration is unknown, there being no firm chemical 
        evidence for its assignment to hand and it having not been  
        established by anomalous dispersion effects in diffraction  
        measurements on the crystal. An arbitrary choice of enantiomer  
        has been made.  
 .    : inapplicable.   

PLAT036 Type_1 Check for missing Flack Parameter s.u.
 No standard uncertainty found for the Flack parameter. 
 When the structure refinement was done with SHELXL97-2, the likely 
 reason for this is a missing BASF instruction. This applies in 
 particular when the associated Flack parameter has the value 0.000.
 No valid conclusions on the absolute structure can be drawn in that case.  

PLAT037 Type_1 Check _diffrn_reflns_theta_full
 No information is given about the theta value for which the dataset is 
 complete, subject to the percentage given with the dataname
 _diffrn_measured_fraction_theta_full.  

PLAT038 Type_1 Check _diffrn_measured_fraction_theta_max
 This fraction should be specified in combination with the theta value  
 given with the dataname _diffrn_reflns_theta_full. 

PLAT039 Type_1 Check _diffrn_measured_fraction_theta_full
 This fraction should be specified in combination with the value for
 _diffrn_reflns_theta_max.  

PLAT040 Type_1 Test for H-atoms [0,1]
 Alert for 'no H-atoms' in CIF. This is unusual for carbon containing compounds,
 but may be correct.

PLAT041 Type_1 Test SumFormula
 In the ideal case, both SumFormula strings (reported and calculated) should
 be identical. If not, the reason for the difference should be clear. Examples  
 are cases where populations do not add up to integer numbers, or when solvent  
 molecules have been SQUEEZED.  
 Note: SHELXL97 reports population parameters in the CIF with two decimals  
 only. This may lead to non-integer atom counts in cases of disorder
 due to rounding.   
 Note: Alerts _041, _042 & _045 can probably be ignored when the relevant   
 values differ by the same factor.  

PLAT042 Type_1 Test MoietyFormula
 In the ideal case, the MoietyFormula string as reported should be identical
 to the MoietyFormula string calculated from the data in the CIF. If not, the   
 reason should be clear. Examples are cases where there is no separating space  
 between two element names or cases where populations do not add up to  
 integer numbers or when moieties are separated by '.' instead of ','.  
 Example: NO3 should be given as N O3   
 Note: Alerts _041, _042 & _045 can probably be ignored when the relevant   
 values differ by the same factor.  

PLAT043 Type_1 Test for MolWeight
 Note: atomic weights used in the calculation of the molecular weight are   
 taken from Inorg. Chim. Acta 217 (1994) 217-218 which deviate in a few cases   
 slightly from the older values used in SHELXL97-2. 
 Note: The tabulated atomic weights that are used may deviate from the  
 actual value in case of special isotopes of e.g. Uranium or Plutonium. 

PLAT044 Type_1 Check Reported with calculated density
 In the ideal case, both data items should be the same within a small   
 tolerance. If not, the reason should be clear. 

PLAT045 Type_1 Check Reported and Calculated Z
 In the ideal case, both data items (Z(calc) & Z(reported)) should be   
 the same. If not, the reason for the difference should be clear. An example
 is the situation where PLATON gives Z = 1 when the program cannot work out 
 a proper Z.
 Note: Alerts _041, _042 & _045 can probably be ignored when the relevant   
 values differ by the same factor.  

PLAT046 Type_1 Check Reported Density with calculated density from Z*MW
 D(calc) as calculated from the reported Z and MW is compared for consistency   
 with the reported d(calc). 

PLAT047 Type_1 Test SumFormula Given
 The Sumformula, corresponding with the Moietyformula, should be given. 

PLAT048 Type_1 Test MoietyFormula Given
 The Moiety formula (i.e. the specification of the various species in the   
 structure) should be given in the CIF. 
 Example: '(Cd 2+)3, (C6 N6Cr 3-)2, 2(H2 O)'

PLAT049 Type_1 Check Calculated Density .GT. 1.0
 The calculated density will with a few exceptions be larger than 1.0.  
 A smaller value may indicate either an incomplete model or incorrect   
 symmetry. (e.g. a missing 'bar' in P-1 etc.)   

PLAT050 Type_1 Test for mu given [0,1]
 The linear absorption coefficient corresponding to the Sumformula should be
 given. 

PLAT051 Type_1 Test for difference mu(cif) with mu(calc) [% "\[\%\]" %]
 In the ideal case, both data items should be the same within a small   
 tolerance. If not, the reason should be clear.
 Note: A significant difference may occur when no elemental mu values are 
 specified on SHELXL .ins DISP records in case of synchrotron based data. 

PLAT052 Type_1 Test for specification absorption correction method [0,1]
 The treatment/method of absorption(correction) should be given explicitly. 
 Set _exptl_absorpt_correction_type to 'none' when no correction is done.
 Other recognized values are 'psi-scan', 'empirical', 'multi-scan', 
 'refdelf', 'analytical', 'numerical', 'gaussian'.  

PLAT053 Type_1 Test for specification xtal_dimension_min [0,1]
 The smallest crystal dimension should be supplied in the CIF.  
 The expected value should be a real number (i.e. not 0.35mm)   

PLAT054 Type_1 Test for specification xtal_dimension_mid [0,1]
 The medium crystal dimension should be supplied in the CIF.
 The expected value should be a real number (i.e. not 0.35mm)   

PLAT055 Type_1 Test for specification xtal_dimension_max [0,1]
 The largest crystal dimension should be supplied in the CIF.   
 The expected value should be a real number (i.e. not 0.35mm)   

PLAT056 Type_1 Test for specification xtal_radius [0,1]
 Spherical correction for absorption is reported. The radius used is not
 supplied.  

PLAT057 Type_3 Test for correction for absorption needed
 You have indicated that an absorption correction has not been applied. 
 (_exptl_absorpt_correction_type 'none'). However, the predicted values of  
 Tmin & Tmax, based on the crystal dimensions given in the CIF, are 
 sufficiently unequal that absorption effects appear to be significant. 
 Therefore, the application of a suitable absorption correction would   
 appear to be required. Also check that the crystal dimensions given in the 
 CIF do represent the actual crystal dimensions as closely as possible. 
 Inaccuracies here can lead to a poor prediction of Tmin & Tmax and give
 rise to these alerts. It should normally be possible to estimate the   
 crystal dimensions to 2 decimal places. Rough estimates to only 1 decimal  
 place may be too inaccurate to provide reliable estimates of Tmin & Tmax.  

PLAT058 Type_1 Test for specification Tmax [0,1]
 The Maximum transmission factor should be specified in the case a correction   
 for absorption was done. This is NOT the value that is calculated  
 automatically with SHELXL when a SIZE instruction is given in the SHELXL   
 instruction file. The values reported by SHELXL represent the EXPECTED 
 correction range. Some correction packages (e.g. SADABS) will provide  
 only one 'relative- correction-factor'. In such cases, Tmax should be  
 given as Tmax-expected and Tmin = relative-correction-factor * Tmax.   

PLAT059 Type_1 Test for specification Tmin [0,1]
 The Minimum transmission factor should be specified in case a correction   
 for absorption was done. This is NOT the value that is calculated  
 automatically with SHELXL when a SIZE instruction is given in the SHELXL   
 instruction file. The values reported by SHELXL represent the EXPECTED 
 correction range. Some correction packages (e.g. SADABS) will provide  
 only one 'relative-correction-factor'. In such cases, Tmax should be   
 given as Tmax-expected and Tmin = relative-correction-factor * Tmax.   

PLAT060 Type_4 RR Test
 see IUCR WEB-Pages 

PLAT061 Type_4 RR' Test
 see IUCR WEB-Pages 

PLAT062 Type_4 Rescale Tmin & Tmax
 Some (empirical) correction packages (e.g. SADABS) will provide only one   
 'relative-correction-factor'. In such cases, Tmax should be given as   
 Tmax-expected (as calculated from the crystal dimensions) and  
 Tmin = relative-correction-factor * Tmax.  

PLAT063 Type_4 Test for Crystal Size
 Alert for crystals with at least one dimension probably too large for the  
 homogeneous part of the X-ray beam when used for datacollection using  
 crystal monochromated radiation. An exception will be datacollection using 
 a beta-filter and a sufficiently large collimator. 
 See also: C.H.Gorbitz (1999), Acta Cryst. B55, 1090-1098.  

PLAT064 Type_1 Test for T(max) .GE. T(min)
 Check that the values entered under _exptl_correction_T_min and
 _exptl_correction_T_max have not been reversed or if there is a
 typographical error for one of these two items.

PLAT065 Type_3 Test for applicability of (semi-)empirical abs.corr. [0,1]
 For high mu * mid values, numerical absorption correction procedures are   
 recommended (either based on Gaussian integration or analytical) in case of
 homogeneous beam profiles and crystals small enough to fit within the  
 homogeneous part of the X-ray beam.
 In case of in-homogeneous beams, a combination of numerical crystal face   
 based correction and multi-scan correction is recommended. 

PLAT066 Type_1 Test whether Predicted and Reported Transmission Ranges are Identical
 The predicted and reported transmission ranges are found to be identical   
 which is not to be expected. CIF's generated with SHELXL97 report  
 transmission ranges based on the crystal dimensions supplied on the
 SIZE card. Those values have nothing to do with the actual corrections 
 for absorption as applied to the data: they just report the EXPECTED range.
 Some correction packages (e.g. SADABS) will provide only one   
 'relative-correction-factor'. In such cases, Tmax should be given as   
 Tmax-expected and Tmin = relative-correction-factor * Tmax.

PLAT067 Type_1 Insure that minimum dimension less max dimension
 Minimum an Maximum dimensions are likely exchanged in the CIF. 

PLAT068 Type_1 Test for F000 Calc/Reported difference
 In the ideal case, both data items should have the same value. If not, 
 the reason should be clear. A reason might be the output by SHELXL 
 of population parameters to the CIF with only two decimals.
 Note: SHELXL counts the number of electrons in the unit cell. The result   
 will in general be an integer. This is also the number checked for here.   
 The official definition calls for 'The effective number of electrons in the
 crystal unit cell contributing to F(000)'. It may contain dispersion   
 contributions and is calculated as:
 F(000) = [ (sum f~r~)^2^ + (sum f~i~)^2^ ]^1/2^
 f~r~ = real part of the scattering factors at theta = 0
 f~i~ = imaginary part of the scattering factors at theta = 0   

PLAT070 Type_1 Test for duplicate labels
 The CIF contains duplicate labels posing interpretation problems for   
 PLATON/CHECK. Derived geometry ALERTS may have their origin in this
 problem.   

PLAT071 Type_1 Test for uninterpretable labels
 The CIF contains labels posing problems for PLATON/CHECK.  
 Example: label HN1 with no scattering type information supplied.   
 Validation is aborted. 

PLAT072 Type_2 Test for extreme first weighting parameter value (SHELXL)
 The first parameter on the SHELXL weighting line has an exceptionally  
 large value. This may indicate either improper reflection s.u.'s or
 an unresolved problem such as missed twinning. 

PLAT073 Type_1 Test for inconsistency 'constr' versus 'H-Atoms refined'
 The structure contains refined hydrogen atoms. However the data item   
 _refine_ls_hydrogen_treatment has the value 'constr'.  
 The value 'mixed' is more appropriate. 

PLAT074 Type_1 Test for Occupancy equal 0.0
 The CIF contains an atom with occupacy less than 0.0001
 Please check whether the zero occupancy specification is intended.

PLAT075 Type_1 Test for Occupancy greater than 1.0
 The CIF contains an atom with Occupancy greater than 1.0.  

PLAT076 Type_1 Test for Occupancy less than 1.0 for atom on special position
 The CIF contains an atom sitting on a special position with occupancy  
 specified as less than 1.0. This is often an error and the result of the   
 confusion of the notions 'occupancy' and 'population parameter'. The first 
 should be 1.0 for a fully occupied site. The latter multiplies the 
 site-symmetry with the occupancy. Thus, for a fully occupied site on a 
 mirror plane the site-symmetry will be 0.5 * 1.0 = 0.5.
 Note: a wrong occupancy number will lead to an incorrect expected  
 chemical formula.  

PLAT077 Type_4 Test for Non-Integral # of atoms in Unit Cell
 The unit-cell contains a non-integer number of atoms of a given atom type. 
 Valid reasons include partially occupied (solvent) sites and substitutional
 disorder.  

PLAT078 Type_1 Test for inconsistency 'geom' versus 'no H-Atoms'
 The structure contains no hydrogen atoms. However the data item
 _atom_sites_solution_hydrogen had the value 'geom'. This value is  
 likely the SHELXL default and should be replaced by '.'.   

PLAT079 Type_1 Test for inconsistency 'mixed' versus 'no H-Atoms'
 The structure contains no hydrogen atoms. However the data item
 _refine_ls_hydrogen_treatment has the value 'mixed'. This value is 
 likely the SHELXL default and should be replaced by '.'.   

PLAT080 Type_2 Test maximum shift/error
 Convergence of the refinement is proved with a close to zero shift/error   
 value for all refined parameters. Such a convergence is easily achieved
 with a few additional refinement cycles at little cost.
 Note: Some SHELXL-97 versions do not allow for negative Flack parameter
 values. Convergence in such a case may be never reached because the
 Flack parameter value is reset to zero.

PLAT082 Type_2 Test for reasonable R1
 A higher than usual R1 indicates either an insufficient model or poor  
 quality data.  

PLAT083 Type_2 Test for extreme second weighting parameter value (SHELXL)
 The second parameter on the SHELXL weighting line has an exceptionally 
 large value. This may indicate either improper reflection s.u.s or
 an unresolved problem such as missed twinning. 

PLAT084 Type_3 Test for reasonable wR2
 wR2 will in general have a value twice of that of R1 with refinement on F**2.  
 Significantly larger values usually indicate a poor refinement model.  
 Also check for unaccounted for twinning.   

PLAT085 Type_2 Test for default SHELXL weighting scheme
 The weighting scheme is found to be left at the SHELXL default.
 This default is recommended for the preliminary structure refinement.  
 It is uncommon that this unoptimized weight gives the best final refinement
 result.

PLAT086 Type_2 Test for reasonable S (Too Low)
 S should in general be close to 1 at the end of a refinement with a proper 
 weighting scheme. If not, there might be significant unresolved problems   
 with the model.

PLAT087 Type_2 Test for reasonable S (Too High)
 S should in general be close to 1 at the end of a refinement with a proper 
 weighting scheme. If not, there might be significant unresolved problems   
 with the model.

PLAT088 Type_3 Test for reasonable Data / parameter ratio (centro)
 The data/parameter ratio should in general be higher than 10 for a quality 
 structure determination. This ratio can be improved by not refining
 C-H parameters other than riding on their carrier atom.

PLAT089 Type_3 Test for reasonable Data / parameter ratio (non-centro) (Zmax < 18)
 The data/parameter ratio should in general be higher than 7 for a quality  
 determination of a structure containing atoms with Z less than 18. 
 This ratio can be improved by not refining C-H parameters other than riding
 on their carrier atom. 
 Note: The number of reflections used in this ratio is the number obtained  
 by Laue group averaging.   

PLAT090 Type_3 Test for reasonable Data / parameter ratio (non-centro) (ZMAX > 18)
 The data/parameter ratio should in general be higher than 8 for a quality  
 determination for a structure containing heavy atoms with ZMAX greater 
 than 17. This ratio can be improved by not refining C-H parameters other   
 than riding on their carrier atom. 

PLAT091 Type_1 Test for 'No-wavelength given'
 No Wavelength specification found in the CIF.  

PLAT092 Type_4 Test for wavelength type [Cu,Ga,Mo,Ag]
 The wavelength, specified in the CIF, is not CuKa = 1.5418A, GaKa = 1.3414A,   
 MoKa = 0.71073A, AgKa = 0.56086A or InKa = 0.51359A radiation within a 
 tolerance of 0.0005A.  Valid exceptions are Neutron and Synchrotron data.  

PLAT093 Type_1 Test for inconsistency 'mixed' versus 'no refined H positions'
 The 'mixed' type Hydrogen atom refinement is reported (SHELXL-97 default). 
 However, no Hydrogen atoms with freely refined positions are found in the  
 CIF. Likely, the value 'constr' or 'refU' for  
 '_refine_ls_hydrogen_treatment' will be more appropriate (e.g. when all
 Hydrogen atoms have been refined in the riding mode on their carrier atom).

PLAT094 Type_2 Test for maximum/minimum residual density ratio
 The ratio of the maximum and minimum residual density excursions is
 unusual. This might indicate unaccounted for twinning or missing atoms 
 (e.g. associated with disordered solvent). 

PLAT095 Type_1 Test for residual density maximum given [0,1]
 No residual electron density maximum given in CIF. 

PLAT096 Type_1 Test for residual density minimum given [0,1]
 No residual electron density minimum given in CIF. 

PLAT097 Type_2 Test maximum residual density (Reported)
 A residual density maximum larger than expected is reported. This might be 
 caused by residual absorption artefacts, unaccounted for twinning, disorder,   
 wrongly assigned atom types, missing hydrogen atoms and other model errors.

PLAT098 Type_2 Test for minimum residual density (Reported)
 A residual density minimum larger than expected is reported. This might be 
 caused by residual absorption artefacts, disorder, wrongly assigned atom   
 types and other model errors.  

PLAT099 Type_1 Test for minimum residual density greater zero [0, 1]
 Likely interchanged maximum and minimum values.
 Alternatively, the minimum residual density has the (unlikely) value   
 zero.  

PLAT104 Type_1 Test for additional translational symmetry [0, 1]
 Check the reported crystal system against the reported space group.
 Alternatively, no crystal system was reported. 

PLAT110 Type_2 Test for additional translational symmetry [0, 1]
 Tests for missed symmetry are done with ADDSYM, an extended MISSYM (C) 
 clone. These tests warn for missed or possible higher (pseudo) symmetry in 
 the structural model (i.e. based on the coordinate data).  
 Close examination of the situation at hand is indicated in order to
 prove/disprove the issue (usually in combination with the reflection data).
 Report on potential (pseudo/real) lattice centering or cell halving.   
 Note: H-atoms and disordered atoms are not taken into account in the tests.

PLAT111 Type_2 Test for additional centre of symmetry [0, 100]
 Tests for missed symmetry are done with ADDSYM, an extended MISSYM (C) 
 clone. These tests warn for missed or possible higher (pseudo) symmetry in 
 the structural model (i.e. based on the coordinate data). Close examination
 of the situation at hand is indicated in order to prove/disprove the issue 
 (usually in combination with the reflection data). 
 This ALERT reports on a potential additional (pseudo/real) inversion centre.   
 A pseudo-centre may be incompatible with existing symmetry elements.   
 Chiral molecules are incompatible with an inversion centre.
 Note: H-atoms and disordered atoms are not taken into account in the test. 

PLAT112 Type_2 Test for additional symmetry [0, 1]
 Tests for missed symmetry are done with ADDSYM, an extended MISSYM (C) 
 clone. These tests warn for missed or possible higher (pseudo) symmetry in 
 the structural model (i.e. based on the coordinate data). Close examination
 of the situation at hand is indicated in order to prove/disprove the issue 
 (usually in combination with the reflection data). 
 This ALERT reports on potential additional (pseudo/real) rotation axes and 
 mirrors.   
 In addition, (pseudo/real) lattice centering/translations are reported as  
 A, B, C, I, X, Y, Z, S. (Here S stands for special and not covered by the  
 preceding types). Full details on the situation at hand should be gleaned  
 from an actual PLATON/ADDSYM run.  
 Chiral molecules are incompatible with an inversion centre or (glide)planes.   
 Note: H-atoms and disordered atoms are not taken into account in the tests.

PLAT113 Type_2 Report New space-group suggested by ADDSYM
 Tests for missed symmetry are done with ADDSYM, an extended MISSYM (C) 
 clone. These tests warn for missed or possible higher (pseudo) symmetry in 
 the structural model (i.e. based on the coordinate data). Close examination
 of the situation at hand is indicated in order to prove/disprove the issue 
 (usually in combination with the reflection data). 
 Chiral molecules are incompatible with an inversion centre or (glide)planes.   
 For an example of reported pseudo-symmetry see I.A.Guzei et al, (2002).
 Acta Cryst. C58, m141-m143.
 Note: H-atoms and disordered atoms (i.e. atoms with population less
 than 1.0) are not taken into account in the tests. This may artificially   
 lead to a symmetry higher than the actual one. 
 Note: Atoms are treated as having the same atom type in order to catch 
 certain types of disorder or incorrect atom type assignment.   

PLAT114 Type_2 Report on ADDSYM problem
 ADDSYM has problems to reconstruct a space group from the symmetry 
 operation found in the symmetry expanded coordinate set. The reason being  
 either intricate additionally detected pseudo-symmetry or serious errors   
 in the data set.   

PLAT115 Type_5 Test for non-crystallographic centre of symmetry [0, 100]
 Tests for missed symmetry are done with ADDSYM, an expanded MISSYM (C) 
 clone. This ALERT reports on local inversion symmetry, not compatible  
 with the reported space-group symmetry.
 Note: H-atoms and disordered atoms are not taken into account in the test. 

PLAT119 Type_1 Report Problem with symmetry operator syntax
 A symmetry operation should be specified in the CIF either without 
 spaces or between quotes.  

PLAT120 Type_1 Test for consistent _symmetry_space_group_name_H-M and Symm Opp
 Space group symmetry should be provided in the CIF both explicitly with a  
 _symmetry_equiv_pos_as_xyz loop and implicitly with
 _symmetry_space_group_name-H-M.
 An unusual (non-standard) choice of origin may also raise this ALERT.  
 Please check and Explain.  

PLAT121 Type_1 Test for valid _symmetry_space_group_name_H-M
 Symmetry in the CIF should be provided both explicitly with a  
 _symmetry_equiv_pos_as_xyz loop and implicitly with
 _symmetry_space_group_name_H-M.
 Test for valid _symmetry_space_group_name_H-M symbol.  

PLAT122 Type_1 Test for ? _symmetry_space_group_name_H-M
 Symmetry in the CIF should be provided both explicitly with a  
 _symmetry_equiv_pos_as_xyz loop and implicitly with
 _symmetry_space_group_name_H-M.
 Test for missing (i.e. ?) _symmetry_space_group_name_H-M symbol.   

PLAT123 Type_1 Test for Interpretable Space Group Symmetry
 Symmetry in the CIF should be provided in the CIF both explicitly with a   
 _symmetry_equiv_pos_as_xyz loop and implicitly with
 _symmetry_space_group_name_H-M or _symmetry_space_group_name_H-M_alt.  
 Test for uninterpretable or inconsistent Space group information.  

PLAT124 Type_1 Test for _symmetry_equiv_pos_as_xyz present
 Symmetry in the CIF should be provided in the CIF both explicitly with a   
 _symmetry_equiv_pos_as_xyz loop and implicitly with
 _symmetry_space_group_name_H-M.
 Test for uninterpretable or absent explicit symmetry records   

PLAT125 Type_4 Test for ? _symmetry_space_group_name_Hall
 Optionally specify the Hall symbol. The Hall symbol provides an
 unambiguous definition of the space-group symmetry where the Hermann-  
 Mauguin symbol leaves room for alternative choices of the origin.  
 E.g. for space-group P21, the screw axis is in general taken to coincide   
 with the b-axis. However, sometimes it is chosen to be shifted by 1/4  
 in the c-axis direction to bring out the relation with P21/c. The Hall 
 symbols will be 'P 2yb' and 'P 2ybc' respectively. 
 Refer to: S.R.Hall, Space Group Notation with an Explicit Origin;  
           Acta Cryst. (1981), A37, 517-525.
       or: http://www.kristall.ethz.ch/LFK/software/sginfo/hall_symbols.html

PLAT126 Type_1 Test for _symmetry_space_group_name_Hall error
 The reported Hall-symbol is found to be in error or uninterpretable.   
 Refer to: S.R.Hall, Space Group Notation with an Explicit Origin;  
           Acta Cryst. (1981), A37, 517-525.
       or: http://www.kristall.ethz.ch/LFK/software/sginfo/hall_symbols.html

PLAT127 Type_1 Test for _symmetry_space_group_name_Hall consistency
 The reported Hall-symbol is found to be inconsistent with the one derived  
 from the explicit symmetry operations. 
 Alternatively, no Hall-symbol could be derived by PLATON for the explicit  
 set of symmetry operations. This may be the case when an unusual origin
 is chosen. 
 Refer to: S.R.Hall, Space Group Notation with an Explicit Origin;  
           Acta Cryst. (1981), A37, 517-525.
       or: http://www.kristall.ethz.ch/LFK/software/sginfo/hall_symbols.html

PLAT128 Type_4 Test for non-standard space_group settings
 P21/n and I2/a etc. settings are often preferred over P21/c and C2/c when  
 that leads to a closer to 90 degrees beta angle.   
 Standard choice of origin is to be preferred. A non-standard origin choice 
 might be useful for for the comparison of related structures.  

PLAT129 Type_4 Test for unusual non-standard Space group name
 The reported space-group name is unusual.  

PLAT130 Type_1 Test for Cubic: a = b = c
 Symmetry constraints on cell dimensions are checked.   

PLAT131 Type_1 Test for Cubic: alpha = beta = gamma = 90
 Symmetry constraints on cell dimensions are checked.   

PLAT132 Type_1 Test for Trigonal/Hexagonal : a = b
 Symmetry constraints on cell dimensions are checked.   

PLAT133 Type_1 Test for Trigonal/Hexagonal : alpha = beta = 90
 Symmetry constraints on cell dimensions are checked.   

PLAT134 Type_1 Test for Trigonal/Hexagonal : gamma = 120
 Symmetry constraints on cell dimensions are checked.   

PLAT135 Type_1 Test for Tetragonal: a = b
 Symmetry constraints on cell dimensions are checked.   

PLAT136 Type_1 Test for Tetragonal: alpha = beta = gamma = 90
 Symmetry constraints on cell dimensions are checked.   

PLAT137 Type_1 Test for Orthorhombic: alpha = beta = gamma = 90
 Symmetry constraints on cell dimensions are checked.   

PLAT138 Type_1 Test for Monoclinic more than 1 angle off 90 degrees
 Symmetry constraints on cell dimensions are checked.   

PLAT139 Type_1 Test for Rhombohedral a = b = c
 Symmetry constraints on cell dimensions are checked.   

PLAT140 Type_1 Test for Rhombohedral alpha = beta = gamma
 Symmetry constraints on cell dimensions are checked.   

PLAT141 Type_4 s.u. on a - axis small or missing
 The s.u. on the a-axis is small or missing. The presence of s.u.'s (where  
 required) and value are checked. S.u.'s as given by the diffractometer 
 software are often much smaller then realistic.

PLAT142 Type_4 s.u. on b - axis small or missing
 The s.u. on the b-axis is small or missing. The presence of s.u.'s (where  
 required) and value are checked. Su's as given by the diffractometer   
 software are often much smaller then realistic.

PLAT143 Type_4 s.u. on c - axis small or missing
 The s.u. on the c-axis is small or missing. The presence of s.u.'s (where  
 required) and value are checked. Su's as given by the diffractometer   
 software are often much smaller then realistic.

PLAT144 Type_4 s.u. on alpha small or missing
 The s.u. on alpha is small or missing. The presence of s.u.'s (where required) 
 and value are checked. Su's as given by the diffractometer software are
 often much smaller then realistic. 

PLAT145 Type_4 s.u. on beta small or missing
 The s.u. on beta is small or missing. The presence of s.u.'s (where required)  
 and value are checked. Su's as given by the diffractometer software are
 often much smaller then realistic. 

PLAT146 Type_4 s.u. on gamma small or missing
 The s.u. on gamma is small or missing. The presence of s.u.'s (where required) 
 and value are checked. Su's as given by the diffractometer software are
 often much smaller then realistic. 

PLAT147 Type_1 s.u. on symmetry restricted cell angle
 There should be no s.u. on symmetry constrained cell angles.   
 Example: No s.u. on alpha, beta and gamma for orthorhombic symmetry.   

PLAT148 Type_3 s.u. on a,b, or c - axis too large
 The s.u. on the reported -axis is unexpectedly large.  

PLAT149 Type_3 s.u. on alpha, beta or gamma too large
 The s.u. on the reported angle is too large.   

PLAT150 Type_1 Check Volume
 An ALERT is issued when the reported unit cell volume differs significantly
 from the volume calculated on the basis of the supplied cell dimensions.   

PLAT151 Type_1 Check for s.u. on Volume
 Missing s.u. on cell volume.   

PLAT152 Type_1 Check for consistency of s.u. on Volume and cell parameters
 Some software packages calculate Volume s.u.'s incorrectly. The correct
 formula  for triclinic, monoclinic and orthorhombic systems
 (based on the propagation of error expression) may be found in:
 M. Nardelli, Computer & Chemistry, (1983), 7, 95-98.   
 or 
 C. Giacovazzo ed. in 'Fundamentals of Crystallography', Second Edition,
 Oxford University Press, 2003,  p135.  
 Also note that several cell parameters for higher symmetry cells are no
 longer independent. S.u. calculations need special treatment in those cases.   

PLAT153 Type_1 test for equal axial s.u.'s
 The reported cell axes s.u.'s are reported equal. Please check whether 
 this is correct or a software default value.   

PLAT154 Type_1 test for equal cell angle s.u.'s
 The reported cell angle s.u.'s are reported equal. Please check whether
 this is correct or a software default value.   

PLAT155 Type_4 Check for reduced cell aP
 Unless for special reasons related to the structure/content, a unit-cell and   
 structure is best reported with reference to the Niggli Reduced Cell.  
 This ALERT may originate also from a failure to order the axes from
 small to large.

PLAT156 Type_4 Check for non-standard axial order
 The axial order should be from small to large in the triclinic cell.   

PLAT157 Type_4 Check for non-standard monoclinic beta angle less 90 Degrees.
 By convention, the Monoclinic beta angle is always chosen to be larger than
 90.0 Degrees. A trivial transformation (1 0 0/0 -1 0/0 0 -1) should be 
 applied to the data.   

PLAT158 Type_4 Check for standard reduced cell
 Unless for special reasons related to the structure/content, a unit-cell and   
 structure is best reported with reference to the Niggli Reduced Cell.  

PLAT161 Type_4 Missing x-coordinate s.u.
 Missing or Zero s.u. (esd) on x-coordinate.
 Positional parameters for all non-hydrogen atoms in general positions are  
 checked for the presence of a non-zero s.u. on them. This includes 
 parameters fixed to fix the origin in polar space-groups which is no longer
 necessary when refinement is done with modern programs (e.g. SHELXL, XTAL).

PLAT162 Type_4 Missing y-coordinate s.u.
 Missing or Zero s.u. (esd) on y-coordinate.
 Positional parameters for all non-hydrogen atoms in general positions are  
 checked for the presence of a non-zero s.u. on them. This includes 
 parameters fixed to fix the origin in polar space-groups (e.g. P21) which  
 is no longer necessary when refinement is done with modern programs
 (e.g. SHELXL, XTAL).   

PLAT163 Type_4 Missing z-coordinate s.u.
 Missing or Zero s.u. (esd) on z-coordinate.
 Positional parameters for all non-hydrogen atoms in general positions are  
 checked for the presence of a non-zero s.u. on them. This includes 
 parameters fixed to fix the origin in polar space-groups (e.g. P41) which  
 is no longer necessary when refinement is done with modern programs
 (e.g. SHELXL, XTAL).   

PLAT164 Type_4 Check for Refined C-H H-Atoms
 Warning: Refined C-H H-atoms in heavy-atom structure (i.e. containing an   
 element beyond element #18). Such H-atoms are in general better refined
 at calculated positions riding on the atoms they are attached to. A
 better data over parameter ratio will be achieved. 

PLAT165 Type_3 Check for R-flagged Non-H Atoms
 Report on restrained (riding) Non-Hydrogen atoms. Note: This may lead to   
 non meaningfull bond and angle s.u.'s (ALERTS _751, _752). 
 R-flagged atoms may arise unintentional being caused by an "AFIX 0" line   
 being missing in a shelxl.ins file (SHELXL-97 refinement). 
 Alternatively, the number of refined parameters may have been limited  
 deliberately (e.g. by refinement of C-F with fixed known geometry, 
 similar to C-H) in order to keep the data/parameter ratio acceptable.  

PLAT166 Type_4 Check for calc flagged atoms with s.u.'s on coordinates
 Calc-flagged atoms are not supposed to carry s.u.'s on their coordinates.  

PLAT169 Type_4 Check for AFIX 1 Record(s) in CIF-Embedded shelxl.res
 The use of 'AFIX 1' record(s) in the SHELXL .res file should be documented in  
 the experimental section of the associated publication.

PLAT170 Type_4 Check for sufficient data in in Atom data loop
 Insufficient data encountered in coordinate loop.  
 A possible cause might be the use of a SHELX style '=' continuation line.  

PLAT171 Type_4 Check for EADP Record(s) in CIF-Embedded shelxl.res
 The use of EADP record(s) in the SHELXL .res file should be documented in the  
 experimental section of the associated publication.

PLAT172 Type_4 Check for DFIX Record(s) in CIF-Embedded shelxl.res
 The use of DFIX record(s) should be documented in the experimental section 
 of the associated publication. 

PLAT173 Type_4 Check for DANG Record(s) in CIF-Embedded shelxl.res
 The use of DANG record(s) should be documented in the experimental section 
 of the associated publication. 

PLAT174 Type_4 Check for FLAT Record(s) in CIF-Embedded shelxl.res
 The use of FLAT record(s) should be documented in the experimental section 
 of the associated publication. 

PLAT175 Type_4 Check for SAME Record(s) in CIF-Embedded shelxl.res
 The use of SAME record(s) n the SHELXL .res file should be documented in the   
 experimental section of the associated publication.

PLAT176 Type_4 Check for SADI Record(s) in CIF-Embedded shelxl.res
 The use of SADI record(s) in the SHELXL .res file should be documented in the  
 experimental section of the associated publication.

PLAT177 Type_4 Check for DELU Record(s) in CIF-Embedded shelxl.res
 The use of DELU record(s) in the SHELXL .res file should be documented in the  
 experimental section of the associated publication.

PLAT178 Type_4 Check for SIMU Record(s) in CIF-Embedded shelxl.res
 The use of SIMU record(s) in the SHELXL .res file should be documented in the  
 experimental section of the associated publication.

PLAT179 Type_4 Check for CHIV Record(s) in CIF-Embedded shelxl.res
 The use of CHIV record(s) in the SHELXL .res file should be documented in the  
 experimental section of the associated publication.

PLAT180 Type_4 Check Rounding of Cell Axes and Angles
 It is unusual that more cell parameters end with a zero and the s.u. is 10.
 This problem might be caused by the specification of insufficient  
 'meaningful' digits as compared to the reported s.u.   
 see also: W.Clegg, Acta Cryst. (2003) E59, e2-e5.  

PLAT181 Type_1 Check for all angles exactly 90 degrees in monoclinic
 One of the angles in a monoclinic cell is expected to be not exactly 90
 degrees.   

PLAT182 Type_1 Check for at least one s.u. greater than zero in monoclinic
 One angle should have an s.u. greater than zero in a monoclinic cell.  

PLAT183 Type_1 Check for _cell_measured_reflns_used value reported
 Please supply the value for _cell_measurement_reflns_used. 

PLAT184 Type_1 Check for _cell_measured_theta_min value reported
 Please supply the value for _cell_measurement_theta_min.   

PLAT185 Type_1 Check for _cell_measured_theta_max value reported
 Please supply the value for _cell_measurement_theta_max.   

PLAT186 Type_4 Check for ISOR Record(s) in CIF-Embedded shelxl.res
 The use of ISOR record(s) in the SHELXL .res file should be documented in the  
 experimental section of the associated publication.

PLAT187 Type_4 Check for RIGU Record(s) in CIF-Embedded shelxl.res
 The use of RIGU record(s) in the SHELXL .res file should be documented in the  
 experimental section of the associated publication.

PLAT193 Type_1 Test for consistency of cell & diffraction temperatures
 The reported _cell_measurement_temperature deviates from the reported  
 _diffrn_ambient_temperature values.

PLAT197 Type_1 Test for specification of unitcell measurement temperature
 Please specify the temperature (Kelvin) at which the unit-cell was 
 determined.

PLAT198 Type_1 Test for specification of Datacollection temperature
 Please specify the temperature (Kelvin) at which the intensity data were   
 collected. 

PLAT199 Type_1 Test for SHELXL Roomtemperature Default (Cell)
 The cell determination temperature is set in the CIF by default by SHELXL97    
 to 293 K when the TEMP instruction is not used. The actual temperature is
 likely either slightly or significantly (in case of a low temperature data
 collection)  different. A likely erroneous temperature of 273K (0C) is
 also flagged. 

PLAT200 Type_1 Test for SHELXL Roomtemperature Default (Datacollection)
 The data collection temperature is set in the CIF by default by SHELXL97 to  
 293 K if the TEMP instruction is not used. A likely erroneous temperature of
 273K (0C) is also flagged. The actual temperature is likely either slightly
 or significantly (for a low temperature data collection) different. 

PLAT201 Type_2 Test for isotropic non-H atoms in main residue(s)
 This test reports on non-hydrogen atoms that were refined with isotropic   
 displacement parameters only in the main residue. Such a practice is unusual   
 by modern standards and only needed for minor disorder modelling.  

PLAT202 Type_3 Test for isotropic non-H atoms in anion ? or solvent ?
 This test reports on isotropically refined atoms in small moieties (usually
 anions or solvent).

PLAT203 Type_2 Test for negative non-Hydrogen U(iso)
 Isotropic U(iso) values are expected to have a positive value. 

PLAT210 Type_3 Test for 'all-isotropic adp(s)
 No anisotropically refined atoms in CIF ?  

PLAT211 Type_2 Test for NPD ADP's (1.0) in main residue(s)
 This test reports on non-positive definite (i.e. complex and unrealistic)  
 anisotropic displacement parameters in the main residue.   

PLAT212 Type_2 Test for NPD ADP's in anion? & solvent ? [0, 1]
 This test reports on non-positive definite (i.e. complex and   
 unrealistic) anisotropic displacement parameters in an anion or solvent
 residue.   

PLAT213 Type_2 Test ratio adp max/min in main residue(s)
 The main axes values of the ADP(S) of the main residue(s) are determined and   
 ordered: U1 < U2 < U3. The value of SQRT(U3/U1) main axis ADP ratio (Angstrom  
 Units) is tested for the main residue(s). Large values may indicate unresolved 
 disorder. Oblate criterium: U3 - U2 < U2 - U1. Prolate otherwise.  

PLAT214 Type_2 Test ratio adp max/min in anion ? or solvent ?
 The main axes values of the ADP(S) of the minor residue(s) are determined and  
 ordered: U1 < U2 < U3. The value of SQRT(U3/U1) main axis ADP ratio (Angstrom  
 Units) is tested for the main residue(s). Large values may indicate unresolved 
 disorder. Oblate criterium: U3 - U2 < U2 - U1. Prolate otherwise.  

PLAT215 Type_3 Test for unusual disordered atom ADP in main residue
 The maximum and minimum main axis ADP ratio (Angstrom Units) is tested for 
 the main residue. Large values may indicate unresolved disorder.   

PLAT216 Type_3 Test for unusual disordered atom ADP in minor residue
 The maximum and minimum main axis ADP ratio (Angstrom Units) is tested for 
 the minor residue(s). Large values may indicate unresolved disorder.   

PLAT217 Type_1 Test for Incomplete UIJ data
 Check & Correct U(aniso) data for completeness etc.
 Do not use SHELX style '=' continuation line   

PLAT218 Type_3 Test for Constrained Uij's
 Uij components have been constrained (i.e. without s.u.) in the refinement.

PLAT220 Type_2 Test Ueq(max)/Ueq(Min) range for non-H atoms in non-solvent
 This test reports on a larger than usual U(eq) range for the specified 
 element type in the non-solvent/anion part of the structure.   
 Too high or too low Ueq's may be an indication for incorrectly 
 identified atomic species (i.e. O versus N).   

PLAT221 Type_2 Test Ueq(max)/Ueq(Min) range for non-H atoms in solvent
 This test reports on a larger than usual U(eq) range for the non-hydrogen  
 atoms solvent/anion. Too high or too low Ueq's may be an indication for
 incorrectly identified atomic species (i.e. Br versus Ag). 

PLAT222 Type_3 Test Uiso(max)/Uiso(Min) range for H atoms in non-solvent
 This test reports on a larger than usual range of U(eq) values for hydrogen
 atoms in the non-solvent/anion part of the structure.  
 Possible causes are:   
 1 - disorder, e.g. in t-butyl moieties.
 2 - poor data, not adequate for the refinement of individual displacement  
     parameters.
 3 - Misplaced hydrogen atoms (i.e. there is no density at the position 
     where one of the H-atoms is positioned).   

PLAT223 Type_4 Test Ueq(max)/Ueq(Min) range for H atoms in solvent
 This test reports on large ranges in displacement parameters for hydrogen  
 atoms in the solvent/anion part of the structure.  

PLAT224 Type_1 Test for difference in implicit and explicit U(eq)
 This test reports on a large difference between Ueq in the CIF and the Ueq 
 calculated from the 6 reported Uij values.                            .

PLAT230 Type_2 Hirshfeld Rigid-Bond Test (Acta Cryst (1976),A32,239-244
 The components of the anisotropic displacement parameters along chemical   
 bonds are assumed to be equal in magnitude. Large differences might
 indicate contamination of these parameters with other (unresolved) effects 
 such as (substitutional) disorder, model or data errors and/or 
 over-refinement. Atomic sites assigned the wrong scattering type (e.g. Ag  
 versus Br) should generate 'problem signals' with this test. Data sets 
 corrected for absorption effects with DELREF techniques (e.g. DIFABS, SHELXA,  
 XABS2) often show large DELU values for bonds involving the heaviest atom. 
 Note: The original 'Hirshfeld-test' was defined in absolute terms (see 
 F.L.Hirshfeld, Acta Cryst. (1976). A32, 239-244). The current test is with 
 reference to the associated standard uncertainty.  

PLAT231 Type_4 Hirshfeld Rigid-Bond Test (Acta Cryst (1976),A32,239-244
 The components of the anisotropic displacement parameters along chemical   
 bonds are assumed to be equal in magnitude. Large differences might
 indicate the contamination of these parameters with other (unresolved) effects 
 such as (substitutional) disorder, model or data errors and/or 
 over-refinement. Atomic sites assigned the wrong scattering type (e.g. Ag  
 versus Br) should generate 'problem signals' with this test. Data sets 
 corrected for absorption effects with DELREF techniques (e.g. DIFABS, SHELXA,  
 XABS2) often show large DELU values for bonds involving the heaviest atom. 
 Note: The original 'Hirshfeld-test' was defined in absolute terms (see 
 F.L.Hirshfeld, Acta Cryst. (1976). A32, 239-244). The current test is with 
 reference to the associated standard uncertainty.  

PLAT232 Type_2 Hirshfeld Rigid-Bond Test (Metal-X) (Acta Cryst (1976),A32,239-244
 The components of the anisotropic displacement parameters along chemical   
 bonds are assumed to be equal in magnitude. Large differences might
 indicate contamination of these parameters with other (unresolved) effects 
 such as (substitutional) disorder, model or data errors and/or 
 over-refinement. Atomic sites assigned the wrong scattering type (e.g. Ag  
 versus Br) should generate 'problem signals' with this test. Data sets 
 corrected for absorption effects with DELREF techniques (e.g. DIFABS, SHELXA,  
 XABS2) often show large DELU values for bonds involving the heaviest atom. 
 A special case are M-C=O type of systems that generally show significant   
 differences for the M-C bond. See D.Braga & T.F. Koetzle (1988), Acta Cryst.   
 B44, 151-155). 
 Note: The original 'Hirshfeld-test' was defined in absolute terms (see 
 F.L.Hirshfeld, Acta Cryst. (1976). A32, 239-244). The current test is with 
 reference to the associated standard uncertainty.  

PLAT233 Type_4 Hirshfeld Rigid-Bond Test (Metal-X) (Acta Cryst (1976),A32,239-244
 The components of the anisotropic displacement parameters along chemical   
 bonds are assumed to be equal in magnitude. Large differences might
 indicate contamination of these parameters with other (unresolved) effects 
 such as (substitutional) disorder, model or data errors and/or 
 over-refinement. Atomic sites assigned the wrong scattering type (e.g. Ag  
 versus Br) should generate 'problem signals' with this test. Data sets 
 corrected for absorption effects with DELREF techniques (e.g. DIFABS, SHELXA,  
 XABS2) often show large DELU values for bonds involving the heaviest atom. 
 Note: The original 'Hirshfeld-test' was defined in absolute terms (see 
 F.L.Hirshfeld, Acta Cryst. (1976). A32, 239-244). The current test is with 
 reference to the associated standard uncertainty.  

PLAT234 Type_4 Hirshfeld Rigid-Bond Test (Acta Cryst (1976),A32,239-244
 The components of the anisotropic displacement parameters along chemical   
 bonds are assumed to be equal in magnitude. Large differences might
 indicate contamination of these parameters with other (unresolved) effects 
 such as (substitutional) disorder, model or data errors and/or 
 over-refinement. Atomic sites assigned the wrong scattering type (e.g. Ag  
 versus Br) should generate 'problem signals' with this test. Data sets 
 corrected for absorption effects with DELREF techniques (e.g. DIFABS, SHELXA,  
 XABS2) often show large DELU values for bonds involving the heaviest atom. 
 Note: The original 'Hirshfeld-test' was defined in absolute terms (see 
 F.L. Hirshfeld, Acta Cryst. (1976). A32, 239-244). 

PLAT241 Type_2 Test for unusually high U(eq) as compared with bonded neighbors
 The U(eq) value of an atom is compared with the average U(eq) for to   
 non-hydrogen atoms bonded to it. Large differences may indicate that the   
 wrong atom type was assigned (e.g. N instead of O).

PLAT242 Type_2 Test for Unusually Low U(eq) as compared with bonded neighbors
 The U(eq) value of an atom is compared with the average U(eq) for  
 non-hydrogen atoms bonded to it. Large differences may indicate that the   
 wrong atom type was assigned (e.g. N instead of O). False alarms may   
 occur for terminal groups such as the t-butyl moiety.  

PLAT243 Type_4 Test for unusually high solvent U(eq) as compared with bonded neighbors
 The U(eq) value of an atom in the solvent or ion is compared with the average  
 U(eq) for non-hydrogen atoms bonded to it. Large differences may indicate  
 that the wrong atom type was assigned (e.g. N instead of O).   

PLAT244 Type_4 Test for unusually low solvent U(eq) as compared with bonded neighbors
 The U(eq) value of an atom in the solvent or ion is compared with the average  
 U(eq) for non-hydrogen atoms bonded to it. Large differences may indicate  
 that the wrong atom type was assigned (e.g. N instead of O). False alarms may  
 occur for terminal groups such as the t-butyl moiety.  

PLAT245 Type_2 Test for unusually low H-U(eq) as compared with bonded atom
 U(iso) of a hydrogen atom is generally expected to be greater than the 
 U(eq) of the non-hydrogen atom it is attached to.  

PLAT250 Type_2 Test for unusual anisotropic average UIJ
 An average value of the U(i,j) tensor of the asymmetric unit of a residue  
 is calculated. An ALERT is generated when the corresponding U3/U1 ratio
 deviates significantly from 1.0. Large values of this ratio should be taken
 as an indication of possible systematic errors in the data or errors in
 the model. Visual inspection of an ORTEP plot will show that many  
 displacement ellipsoids have their major axis pointing in the same direction.  

PLAT260 Type__260 .100 0.30 1.00 2 A 0 0 3 0 Test for high average Ueq for residue
 A large average Ueq value for a residue may indicate refinement with a too 
 high (possibly fixed) population parameter value.

PLAT300 Type_4 Test for Fixed Partial Occupancy
 This site is expected to be fully occupied but has been constrained (e.g.  
 with a SHELXL FVAR variable) or fixed at a value less than 1.0. Please check   
 for incomplete (substitutional) disorder handling. 

PLAT301 Type_3 Test for main residue(s) disorder %
 Atom sites that are not fully occupied are counted. A large fraction of
 disordered atoms may be both a signal for serious structure analysis   
 problems or less reliable/interesting results. 

PLAT302 Type_4 Test for (anion/solvent) disorder %
 Atom sites that are not fully occupied are counted.

PLAT303 Type_2 Test for more than 1 connection to Hydrogen Atoms
 Hydrogen atoms are generally connected to only one other atom. A hydrogen  
 atom between two oxygen atoms is a special case. Investigate whether this  
 hydrogen atom is better described with a disorder model with two partially 
 occupied sites. A difference map might show a double-well density. 

PLAT304 Type_4 Test for non-integer number of atoms in residue
 A non-integer number of atoms has been found in a residue. 

PLAT305 Type_2 Test for isolated Hydrogen Atoms
 This test reports on hydrogen atoms that are not on bonding distance to any
 atom. This ALERT may indicate that the hydrogen atom refined to a  
 non-bonding position or needs a symmetry operation to bring it to bonding  
 distance. It also may indicate a problem with incompatible population  
 parameters (e.g. C - H with population 0.8 and 0.9 respectively).  

PLAT306 Type_2 Test for isolated Oxygen Atoms
 This test reports on oxygen atoms that are not within bonding distance to  
 any other atom in the structure. A common reason may be that no hydrogen   
 atoms are given for a water molecule. Attempts should be made to locate
 those hydrogen atoms from a difference map.

PLAT307 Type_2 Test for isolated Metal Atoms
 This test reports on metal atoms that are not bonded or at coordination
 distance of other atoms. Isolated ions are very unusual (or non-existent ?)

PLAT308 Type_2 Test for single bonded Metal Atoms
 This test reports on single bonded (coordinated) metal atoms/ions. This
 represents a very unusual situation. There are literature examples where such  
 a 'single bonded metal' was shown to be a halogen. 

PLAT309 Type_2 Test for single bonded Oxygen Atoms
 Single bonded Oxygen with C-O > 1.3 Angstrom. Missing H-Atom ? Check   

PLAT310 Type_2 Test for 'too close' (symmetry related) full weight atoms
 This test identifies (very) short contacts between atoms that only becomes 
 apparent after the application of symmetry on the primary coordinate set.  

PLAT311 Type_2 Test for isolated Disordered Oxygen Atoms
 This test reports on oxygen atoms (not full weight) that are not within
 bonding distance to any other atom in the structure.   
 A common reason may be that no hydrogen atoms are given for a water molecule.  

PLAT312 Type_2 Test for C=O-H
 Strange C-O-H geometry with C-O  <   1.25 Angstrom detected. Misplaced 
 H-Atom ?   

PLAT313 Type_2 Test for O with three covalent bonds
 Oxygen atom with three covalent bonds detected. Check for correct atom type
 assignment (e.g. N rather than O)  
 Note: Exceptions are H3O+ (Oximium or Hydroxonium) and 
                      H5O2+ (Hydronium or aqua-hydroxonium) species.

PLAT314 Type_2 Test for Metal-O-H angle of H2O
 A water molecule coordinated to a metal is detected with an unusually  
 small value of the Metal-Oxygen-Hydrogen Angle.

PLAT315 Type_2 Test for single bonded Carbon atom
 Check for missing H-atoms.

PLAT316 Type_2 Check for too many H's on C in C=N bond in main residue(s)
 An sp3 hybridized C was detected as part of a C=N moiety. Only one 
 attached H atom in sp2 configuration is expected and not two.  
 In SHELXL terms this corresponds with an erroneous AFIX 23 rather than an  
 AFIX 43 type of H atom position generation and refinement. 

PLAT317 Type_2 Check for too many H's on C in C=N bond in Solvent/Ion (s)
 An sp3 hybridized C was detected as part of a C=N moiety. Only one 
 attached H atom in sp2 configuration is expected and not two.  
 In SHELXL terms this corresponds with an erroneous AFIX 23 rather than an  
 AFIX 43 type of H atom position generation and refinement. 

PLAT318 Type_2 Hybridisation Problem on N in main residue(s)
 The test attempts to assign one of three hybridisations to N atoms in main 
 residue: sp, sp2 or sp3 on the basis of the angles around N.   
 This ALERT may indicate a mis-assigned H atom position (e.g. an atom   
 placed in a sp2 position instead of sp3).  

PLAT319 Type_2 Hybridisation Problem on N in solvent/ion
 The test attempts to assign one of three hybridisations to N atoms in main 
 residue: sp, sp2 or sp3 on the basis of the angles around N.   
 This ALERT may indicate a mis-assigned H atom position (e.g. an atom   
 placed in a sp2 position instead of sp3).  

PLAT320 Type_2 Hybridisation Problem on C in main residue(s)
 The test attempts to assign one of three hybridisations to C atoms in main 
 residue: sp, sp2 or sp3 on the basis of the angles around C. In this way,  
 missing H atoms or too many H-atoms on a carbon atom should be detected.   

PLAT321 Type_2 Hybridisation Problem on C in solvent/ion
 The test attempts to assign one of three hybridisations to C atoms in  
 solven/anion: sp, sp2 or sp3 on the basis of the angles around C. In this  
 way missing H atoms or too many H-atoms on a carbon atom should be detected.   

PLAT322 Type_2 Hybridisation Problem on non-C in main residue(s)
 The test attempts to assign one of three hybridisations to a non-C atom in 
 the main residue: sp, sp2 or sp3 on the basis of the angles around the 
 non-C atom. In this way, missing H atoms or too many H-atoms should be 
 detected.  

PLAT323 Type_2 Hybridisation Problem on non-C in Solvent/Ion
 The test attempts to assign one of three hybridisations to a non-C atom in 
 the solvent/anion: sp, sp2 or sp3 on the basis of the angles around the
 non-C atom. In this way, missing H atoms or too many H-atoms should be 
 detected.  

PLAT324 Type_2 Check for possibly missing H on coordinating X-N-X in main residue
 Check for possibly missing Hydrogen atom on Nitrogen coordinating to   
 a metal in the main residue.   

PLAT325 Type_2 Check for possibly missing H on coordinating X-N-X in solvent/anion
 Check for possibly missing Hydrogen atom on Nitrogen coordinating to   
 a metal in the solvent/anion.  

PLAT326 Type_2 Check for possibly missing H on potentially sp3 Carbon
 Check for possibly missing Hydrogen atom on Carbon with sp3-like geometry  
 in the main residue.   

PLAT327 Type_2
 Check for possibly missing Hydrogen atom on Carbon with sp3-like geometry  
 in the solvent/anion.  

PLAT328 Type_4 Check for a possibly missing H on potentially sp3 Phosphorus
 Check for a possibly missing Hydrogen atom on Phosphorus with sp3-like 
 geometry.  

PLAT329 Type_4 Check for unclear Carbon Atom Hybridisation
 
 The hybridisation of this calbon atom could not be established from the 
 number of substituents and their geometry. Check for missing hydrogen atoms
 and/or poor geometry. 

PLAT330 Type_2 Check Average Phenyl C-C
 The standard average C-C bond distance in a phenyl ring is 1.395 Angstrom. 
 The actual average ring distance may be larger than expected due to
 systematic errors in the cell dimensions (e.g. use of incorrect
 wavelength value for the determination of the cell parameters).

PLAT331 Type_2 Check Average Phenyl C-C
 The standard average C-C bond distance in a phenyl ring is 1.395 Angstrom. 
 The average ring distance may be smaller due to large thermal motion or
 incorrect cell dimensions. 

PLAT332 Type_2 Check Phenyl C-C Range
 The standard average C-C in a phenyl ring is 1.395 Angstrom. Bond distances
 in the ring are expected to vary only slightly due to thermal motion or
 substituent effects. Large deviations are likely due to data or model errors.  

PLAT333 Type_2 Check Average in Multiple Substituted Benzene Type C-C
 The standard average C-C bond distance in a flat six carbon atom containing
 aromatic ring is 1.395 Angstrom.   
 The actual average ring distance may be larger than expected due to
 substituents such as '=O', single bonds or systematic errors in the cell   
 dimensions (E.g. when the wrong wavelength is used in the derivation of
 the cell parameters).  

PLAT334 Type_2 Check Average in Multiple Substituted Benzene Type C-C
 The standard average C-C bond distance in a benzene ring is 1.395 Angstrom.
 The average ring distance may be smaller due to large thermal motion,  
 substituents such as '=O' or incorrect cell dimensions.

PLAT335 Type_2 Check Multiple Substituted Benzene Type C-C Range
 The standard average C-C bond distance in a benzene ring is 1.395 Angstrom.
 Bond distances in the ring are expected to vary only slightly when due to  
 substituent effects (exceptions include =O substituents). Large deviations 
 may indicate data or model errors. 

PLAT336 Type_2 Check Unusual Bond Distance
 Check this bond distance.  

PLAT338 Type_4 Check Average Torsion Angle in cyclo-hexane ring
 Cyclohexane moieties should have be significantly puckered as measured by  
 the average torsion angle tau. Unresolved disorder generally results in
 flattened rings and elongated displacement ellipsoids. A disorder model
 should be included in the calculations.

PLAT340 Type_3 Check Bond Precision for C-C in Light Atom Structures (Z(max) < 20)
 The average s.u. for X-Y bonds is tested (named bond-precision). X-Y will  
 generally be C-C bonds, unless there are none. In the last case the s.u.'s of  
 the lowest element numbers are considered (excluding hydrogen). There are  
 three test ranges: one for structures with the largest element Z < 20, one 
 for the largest Z in the range 20 to 39 and one for structures with Z(max) 40  
 or higher (_340, _341 and _342 respectively)   

PLAT341 Type_3 Check Bond Precision for C-C in Structures (19 < Z(max) < 40)
 The average s.u. for X-Y bonds is tested (named bond-precision). X-Y will  
 generally be C-C bonds, unless there are none. In the last case the s.u.'s of  
 the lowest element numbers are considered (excluding hydrogen). There are  
 three test ranges: one for structures with the largest element Z < 20, one 
 for the largest Z in the range 20 to 39 and one for structures with Z(max) 40  
 or higher (_340, _341 and _342 respectively)   

PLAT342 Type_3 Check Bond Precision for C-C in Structures (Z(max) > 39)
 The average s.u. for X-Y bonds is tested (named bond-precision). X-Y will  
 generally be C-C bonds, unless there are none. In the last case the s.u.'s of  
 the lowest element numbers are considered (excluding hydrogen). There are  
 three test ranges: one for structures with the largest element Z < 20, one 
 for the largest Z in the range 20 to 39 and one for structures with Z(max) 40  
 or higher (_340, _341 and _342 respectively)   

PLAT343 Type_2 Hybridisation Problem on C in main residue(s)
 The angle range is larger than usual for the tentatively assigned  
 hybridisation of the reported atom in the main residue.

PLAT344 Type_2 Hybridisation Problem on C in solvent/ion
 The angle range is larger than usual for the tentatively assigned  
 hybridisation of the reported atom in the solven/anion.

PLAT350 Type_3 Test for short C - H (Angstrom Difference) XRAY: 0.96 NEUT 1.08
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc.  Default C-H = 0.96 Ang. (X-Ray) value from SHELXL.   

PLAT351 Type_3 Test for long C - H (Angstrom Difference) XRAY: 0.96 NEUT 1.08
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc.  Default C-H = 0.96 Ang. (X-Ray) value from SHELXL.   

PLAT352 Type_3 Test for short N - H (Angstrom Difference) XRAY: 0.87 NEUT 1.009
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc.  Default N-H = 0.87 Ang. (X-Ray) value from SHELXL.   

PLAT353 Type_3 Test for long N - H (Angstrom Difference) XRAY: 0.87 NEUT 1.009
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc.  Default N-H = 0.87 Ang. (X-Ray) value from SHELXL.   

PLAT354 Type_3 Test for short O - H (Angstrom Difference) XRAY: 0.82 NEUT 0.983
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc.  Default O-H = 0.82 Ang. (X-Ray) value from SHELXL.   

PLAT355 Type_3 Test for long O - H (Angstrom Difference) XRAY: 0.82 NEUT 0.983
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc.  Default O-H = 0.82 Ang. (X-Ray) value from SHELXL.   

PLAT356 Type_3 Test for short B-H distance
 A short B-H distance may be due to fixing that distance to a wrong value,
 e.g. to that of the C-H distance in a CH3 group.

PLAT357 Type_3 Test for long B-H distance
 Check the long reported B-H bond distance (B-H is expected to have a value
 around 1.16 Ang in a BH3 group)

PLAT360 Type_2 Test for short C4 - C4 (Angstrom Difference) XRAY: 1.54
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C4-C4 = 1.54 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C4-C4 indicates a bond between atoms with 4 bonds each. 

PLAT361 Type_2 Test for long C4 - C4 (Angstrom Difference) XRAY: 1.54
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C4-C4 = 1.54 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C4-C4 indicates a bond between atoms with 4 bonds each. 

PLAT362 Type_2 Test for short C4 - C3 (Angstrom Difference) XRAY: 1.52
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C4-C3 = 1.52 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C4-C3 indicates a bond between an atom with 4 bonds and one with 3 bonds.   
  - Conjugated systems may cause some 'false alarm' messages.   

PLAT363 Type_2 Test for long C4 - C3 (Angstrom Difference) XRAY: 1.52
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C4-C3 = 1.52 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C4-C3 indicates a bond between an atom with 4 bonds and one with 3 bonds.   
  - Conjugated systems may cause some 'false alarm' messages.   

PLAT364 Type_2 Test for short C4 - C2 (Angstrom Difference) XRAY: 1.46
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C4-C2 = 1.46 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C4-C2 indicates a bond between an atom with 4 bonds and one with 2 bonds.   
  - Conjugated systems may cause some 'false alarm' messages.   

PLAT365 Type_2 Test for long C4 - C2 (Angstrom Difference) XRAY: 1.46
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C4-C2 = 1.46 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C4-C2 indicates a bond between an atom with 4 bonds and one with 2 bonds.   
  - Conjugated systems may cause some 'false alarm' messages.   

PLAT366 Type_2 Test for short C? - C? (Angstrom Difference) XRAY: 1.50
 The hybridisation of at least one carbon atom is not recognized.   
 Large deviations from generally accepted values for a C-C bond may indicate
 model problems, unresolved disorder, over_refinement etc. The C-C bond is  
 tested to be not shorter than 1.15 Angstrom.   

PLAT367 Type_2 Test for long C? - C? (Angstrom Difference) XRAY: 1.50
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C?-C? = 1.50 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 

PLAT368 Type_2 Test for short C3 - C3 (Angstrom Difference) XRAY: 1.34
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C3-C3 = 1.34 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C3-C3 indicates a bond between atoms with 3 bonds each. 
  - Conjugated systems may cause some 'false alarm' messages.   

PLAT369 Type_2 Test for long C3 - C3 (Angstrom Difference) XRAY: 1.34
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc.  Default C3-C3 = 1.34 Ang. (X-Ray) value from 
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C3-C3 indicates a bond between atoms with 4 with 3 bonds each.  
  - Conjugated systems may cause some 'false alarm' messages.   
  - A notable exception is the C-C bond in -C(=O)-C(=O)- systems with an
    observed mean value of 1.54 Angstrom.   

PLAT370 Type_2 Test for short C3 - C2 (Angstrom Difference) XRAY: 1.31
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C3-C2 = 1.31 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C3-C2 indicates a bond between an atom with 3 bonds and one with 2 bonds.   
  - Conjugated systems may cause some 'false alarm' messages.   

PLAT371 Type_2 Test for long C3 - C2 (Angstrom Difference) XRAY: 1.31
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C3-C2 = 1.31 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C3-C2 indicates a bond between an atom with 3 bonds and one with 2 bonds.   
  - Conjugated systems may cause some 'false alarm' messages.   

PLAT372 Type_2 Test for short C2 - C2 (Angstrom Difference) XRAY: 1.25
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C2-C2 = 1.25 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C2-C2 indicates a bond between atoms with 2 bonds each. 
  - Conjugated systems may cause some 'false alarm' messages.   

PLAT373 Type_2 Test for long C2 - C2 (Angstrom Difference) XRAY: 1.25
 Large deviations from generally accepted values may indicate model problems,   
 over refinement etc. Default C2-C2 = 1.25 Ang. (X-Ray) value from  
 Ladd & Palmer, Structure Determination by Xray Crystallography (1985). 
 Note:  
  - C2-C2 indicates a bond between atoms with 2 bonds each. 
  - Conjugated systems may cause some 'false alarm' messages.   

PLAT374 Type_2 Test for long N - N Bond (> 1.45 Angstrom)
 Large deviations from generally observed bond distances may indicate model 
 problems, over-refinement etc. Check for wrong atom-type assignments.  
 For an example see: Acta Cryst. (2003) E59, m710-m712. 

PLAT375 Type_2 Test for C-O-H with large C-O Distance
 Strange C-O-H geometry with C-O  >   1.45 Angstrom detected.   
 Wrong Atom Type ?  

PLAT380 Type_4 Test for incorrectly Oriented Methyl Moiety
 This test alerts for possible incorrectly oriented CH3 moieties.   
 (E.g. AFIX 33 instead of AFIX 137 etc. within the SHELXL realm)

PLAT390 Type_3 Test Methyl Moiety X-C-H Bond Angle
 Unusual Methyl Moiety X-C-H Angle (Ideally 109 Degrees for 4-bonded C).

PLAT391 Type_3 Test Methyl Moiety H-C-H Bond Angle
 Unusual Methyl Moiety H-C-H Angle (ideally 109 Degrees).   

PLAT395 Type_2 Test general X-O-Y Angle Value
 The X-O-Y angle value differs from the common ~120.0 Degrees.  

PLAT396 Type_2 Test Si-O-Si Angle Value
 The Si-O-Si angle value differs from the common ~150.0 Degrees.

PLAT397 Type_2 Test B-O-B Angle Value
 The B-O-B angle differs significantly from 120.0 degrees.  
 This is just a notice: B-O-B angles vary widely depending on what is bonded
 to the Boron atoms.

PLAT398 Type_2 Test C-O-C Angle Value
 The C-O-C angle value differs from the common ~120.0 Degrees.  

PLAT410 Type_2 Test for short non-bonding intra H..H contacts
 Short intramolecular contacts may arise when H-atoms are in (false)
 calculated positions. Short intramolecular contacts may also be a sign for a   
 false structure with the molecule sitting on a site with improper site 
 symmetry (e.g. '2' instead of '-1') which may happen when a lattice
 translation is missed. Short contacts are defined using a van der Waals
 radius of 1.2 Angstrom. For intramolecular contacts alerts are generated   
 for contacts less than 2.0 Angstrom.   

PLAT411 Type_2 Test for short non-bonding inter H..H contacts
 Short intermolecular H..H contacts may indicate incorrectly determined 
 structures (i.e. wrong symmetry, missed translation symmetry, wrong position   
 with reference to the symmetry elements, hydrogen atoms on atoms where there   
 should not be any  etc..)  
 Short intermolecular contacts may be indicative for inconsistent symmetry  
 data (e.g. coordinates for space-group P43 and symmetry specified as P41 or
 P21/n & P21/c confusions). Short contacts are defined using a van der Waals
 radius of 1.2 Angstrom. For intermolecular contacts, an alert is generated 
 for contacts less than 2.4 Angstrom.   

PLAT412 Type_2 Test for short non-bonding intra H..H contacts (involving XH3)
 Short intramolecular contacts may arise when H-atoms are in (false)
 calculated positions. Short intramolecular contacts may also be a sign for a   
 false structure with the molecule sitting on a site with improper site 
 symmetry (e.g. '2' instead of '-1') which may happen when a lattice
 translation is missed. Short contacts are defined using a van der Waals
 radius of 1.2 Angstrom. Short H .. H contact involving CH3 H-atoms are often   
 hampered by the fact that they involve H atoms at not optimal calculated   
 positions. 

PLAT413 Type_2 Test for short non-bonding inter H..H contacts (involving XH3)
 Short intermolecular H..H contacts may indicate incorrectly determined 
 structures (i.e. wrong symmetry, missed translation symmetry, wrong position   
 with reference to the symmetry elements, hydrogen atoms on atoms where there   
 should not be any  etc..). Short intermolecular contacts may be indicative 
 for inconsistent symmetry data (e.g. coordinates for space-group P43 and   
 symmetry specified as P41 or P21/n & P21/c confusions). Short contacts are 
 defined using a van der Waals radius of 1.2 Angstrom. Short H .. H contact 
 involving CH3 H-atoms are often hampered by the fact that they involve 
 H atoms at not optimal calculated positions.   

PLAT414 Type_2 Test for short non-bonding intra D-H..H-X contacts
 Short intra D-H..H-X contact. This might be a di-hydrogen bond of the type
 B-H..H-O.  See Crabtree et al. Acc. Chem. Res. 1996, 29, 348-354. 

PLAT415 Type_2 Test for short non-bonding inter D-H..H-X contacts
 Short inter D-H..H-X contact. This might be a di-hydrogen bond of the type
 B-H..H-O. See: Crabtree et al. Acc. Chem. Res. 1996, 29, 348-354. 

PLAT416 Type_2 Test for short non-bonding intra D-H..H-D contacts
 Short non-bonding intra D-H..H-D contacts may be related to disordered or  
 misplaced H-atoms. 

PLAT417 Type_2 Test for short non-bonding inter D-H..H-D contacts
 Short non-bonding inter D-H..H-D contacts may be related to disordered or  
 misplaced H-atoms. 
 Experience has shown that any intermolecular H...H separation of less than 
 1.8 Angstroms between unit-occupancy H atoms is a clear indicator that one 
 or both of these H atoms may be wrongly placed.

PLAT420 Type_2 Test for D-H without acceptor
 Potential hydrogen bond donors are checked for the presence of suitable
 acceptors using commonly used (Jeffrey) H-bond criteria. As a general rule 
 there should be an acceptor for each donor. Exceptions are very rare for O-H   
 and more common for -NH and -NH2. A common error is an -OH on a calculated 
 position pointing in the wrong direction.  

PLAT430 Type_2 Test for short non-bonding inter D...A contacts
 This test alerts for possibly missed Hydrogen bonds as indicated by short  
 (i.e. shorter than sum of the van der Waals radii - 0.2 Angstrom)  
 Donor - Acceptor distances.
 Note: Short C=O .. O=C are observed sometimes when part of three-centre
 O-H, N-H or C-H O..O bridging. 

PLAT431 Type_2 Test for short non-bonding inter HL...A contacts
 This test reports on short intermolecular Halogen .. Donor/Acceptor
 atom-type distances.   

PLAT432 Type_2 Test for short non-bonding inter X...Y contacts
 This test raised an ALERT for short intermolecular contacts.   
 In general, intermolecular contact distances should be not much smaller than   
 the sum of the associated van der Waals Radii. More often than not, such   
 short contacts can be a warning sign for errors. All short contacts should 
 therefore be examined in some detail. Interesting exceptions are carbonyl- 
 carbonyl interactions that often feature short O...C contacts (see Allen   
 et al. (1998) B54, 320-329, short NO2 O...O interactions and BF4(-) to 
 (aromatic) carbon contacts.

PLAT433 Type_4 Test for short non-bonding minor..minor inter X...Y contacts
 This test raised an ALERT for short intermolecular contacts between minor  
 disorder components. In general, intermolecular contact distances should be
 not much smaller than the sum of the associated van der Waals Radii. More  
 often than not, such short contacts can be a warning sign for errors. All  
 short contacts should therefore examined in some detail. Interesting   
 exceptions are carbonyl-carbonyl interactions that often feature short O...C   
 contacts (see Allen et al. (1998) B54, 320-329.

PLAT434 Type_2 Test for short non-bonding inter HL...HL contacts
 This test reports on short intermolecular Halogen .. Halogen type distances.   

PLAT480 Type_4 Test for too large H...A
 Check this (unrealistically) long reported H..A contact.   
 Jeffrey criterium: Contact  <   vdWR(H) + vdWR(A) - 0.12 Angstrom. 

PLAT481 Type_4 Test for too large D...A
 Check this (unrealistically) long reported D..A contact.   
 Jeffrey criterium: Contact  <   vdWR(D) + vdWR(A) + 0.50 Angstrom. 

PLAT482 Type_4 Test for too small D-H...A Angle
 Check this unrealistically small reported D-H..A Angle.
 Jeffrey criterium: D-H..A Angle > 100 degrees. 

PLAT601 Type_2 Test for (Unreported) solvent accessible voids
 Crystal structures in general do not contain large solvent accessible voids
 in the lattice. Most structures lose their long-range ordering when solvent
 molecules leave the crystal. Only when the remaining network is strongly   
 bonded (e.g. zeolites and some hydrogen bonded networks) the crystal   
 structure may survive. 
 Residual voids in a structure may indicate the omission of (disordered)
 density from the model. Disordered density may go undetected when smeared  
 since peak search programs are not designed to locate maxima on density
 ridges. The presence or absence of residual density in the void may be 
 verified on a printed/plotted difference Fourier map or with PLATON/SQUEEZE.   
 Voids of 40 Ang**3 may accommodate H2O. Small molecules such as
 Tetrahydrofuran have typical volumes in the 100 to 200 Ang**3 range.   
 This test reports the volume of the largest solvent accessible void in the 
 structure. 
 A paper reporting a crystal structure with a significant solvent accessible
 void should at the least discuss the issue.

PLAT602 Type_2 Test for TOO LARGE (Unreported) solvent accessible voids
 This test reports on a solvent accessible void in the structure, too large 
 or too time consuming for the current PLATON version for a more detailed   
 analysis as part of the validation run. Use the SOLV option for more details.  
 Such a warning might also indicate that the symmetry is incomplete 
 e.g. should have been specified as P-1 and not P1, leaving out half of 
 the unit cell content. 

PLAT603 Type_4 Test for TOO LARGE Unit Cell for VOID search
 No search for solvent accessible VOIDS done as part of VALIDATION in   
 view of large unit-cell.   

PLAT604 Type_4 Test for TOO Many VOIDS
 Too many solvent accessible VOIDS. 

PLAT605 Type_4 Test for (Reported) solvent accessible voids
 Crystal structures in general do not contain large solvent accessible voids
 in the lattice. Most structures lose their long-range ordering when solvent
 molecules leave the crystal. Only when the remaining network is strongly   
 bonded (e.g. zeolites and some hydrogen bonded networks) the crystal   
 structure may survive. 
 Residual voids in a structure may indicate the omission of (disordered)
 density from the model. Disordered density may go undetected when smeared  
 since peak search programs are not designed to locate maxima on density
 ridges. The presence or absence of residual density in the void may be 
 verified on a printed/plotted difference Fourier map or with PLATON/SQUEEZE.   
 Voids of 40 Ang**3 may accommodate H2O. Small molecules such as
 Tetrahydrofuran have typical volumes in the 100 to 200 Ang**3 range.   
 This test reports the volume of the largest solvent accessible void in the 
 structure. 
 A paper reporting a crystal structure with a significant solvent accessible
 void should at the least discuss the issue.
 Note: The use of PLATON/SQUEEZE was reported in the CIF

PLAT606 Type_4 Test for TOO LARGE (Reported) solvent accessible voids
 This test reports on a solvent accessible void in the structure, too large 
 or too time consuming for the current PLATON version for a more detailed   
 analysis as part of the validation run. Use the SOLV option for more details.  
 Such a warning might also indicate that the symmetry is incomplete 
 e.g. should have been specified as P-1 and not P1, leaving out half of 
 the unit cell content. 

PLAT607 Type_4 Test for Skipped VOID Test
 Void test Skipped  

PLAT608 Type_4 Test for too many atoms for ADDSYM test as part of CheckCIF
 The ADDSYM test is skipped as part of the checkCIF run when the symmetry
 generated cell content gets too large and the calculation too time consiming.
 The calculation can still be done via the ADDSYM tool in PLATON.  

PLAT650 Type_4 Report the use of the SHELXL/SWAT Instruction
 This test reports the use of the SHELXL/SWAT instruction for the modelling
 of the disordered solvent contribution to the calculated structure factors.   

PLAT660 Type_1 Test for radiation type specification
 
 Examples of expected values are 'MoKa', 'synchrotron', 'neutron', 'electron' 

PLAT699 Type_1 Test for _exptl_crystal_description value
 
 Examples of expected values are 'block', 'needle', 'plate', 'sphere',
 'cylinder'. In case of 'cylinder' or 'sphere' also provide a value for
 '_exptl_size_rad'.                   

PLAT701 Type_1 Test for consistency of Bonds and Coordinates in CIF
 Bond distances given in the CIF are cross-checked with corresponding   
 values calculated from the coordinates.  Alerts are set at 1,2 and 3 sigma 
 deviation levels.  
 Note: Default s.u.'s are used where no s.u. given (e.g. for C-H)   
 In general, all differences should be within the associated s.u.   
 Small differences may arise from rounding. 
 Very large deviation (or zero distance) normally indicate incorrectly  
 specified symmetry operations on the associated atoms, or 'cut-and-pasting'
 of incompatible CIF's. 

PLAT702 Type_1 Test for consistency of Angles and Coordinates in CIF
 Bond Angles given in the CIF are cross-checked with corresponding values   
 calculated from the coordinates.  Alerts are set at 1,2 and 3 sigma
 deviation levels.  
 In general, all differences should be within the associated s.u.   
 Small differences may arise from rounding. Very large deviations normally  
 indicate incorrectly specified symmetry operations on the associated atoms,
 or 'cut-and-pasting' of incompatible CIF's.

PLAT703 Type_1 Test for consistency of Torsions and Coordinates in CIF
 Torsion angles given in the CIF are cross-checked with corresponding values
 calculated from the coordinates.  Alerts are set at 1,2 and 3 sigma
 deviation levels.  
 In general, all differences should be within the associated s.u.   
 Small differences may arise from rounding. Very large deviations normally  
 indicate incorrectly specified symmetry operations on the associated atoms,
 or 'cut-and-pasting' of incompatible CIF's.

PLAT704 Type_1 Test for consistency of Contact Distances and Coordinates in CIF
 Intermolecular contacts listed in the CIF are checked against the  
 coordinates in the CIF.
 Alerts are set at 1,2 and 3 sigma deviation levels.

PLAT705 Type_1 Test for consistency of H-Bond D-H distances and Coordinates in CIF
 Hydrogen-Bond D-H listed in the CIF is checked.  Alerts are set at 
 1,2 and 3 sigma deviation levels.  

PLAT706 Type_1 Test for consistency of H-Bond H..A Distances and Coordinates in CIF
 Hydrogen-Bond H..A listed in the CIF is checked. Alerts are set at 1,2 and 
 3 sigma deviation levels.  
 This ALERT is generally related to incorrect symmetry codes. The symmetry  
 number s in the symmetry code s_pqr should correspond to the expression
 for s in the CIF. Those expressions can be different for different 
 software packages. E.g. pasting H-bond table data generated with PLATON
 into a CIF generated with SHELXL may raise this ALERT. Manual correction   
 of the symmetry code should be trivial.

PLAT707 Type_1 Test for consistency of H-Bond D..A Distances and Coordinates in CIF
 Hydrogen-Bond D..A listed in the CIF is checked. Alerts are set at 1,2 and 
 3 sigma deviation levels.  
 This ALERT is generally related to incorrect symmetry codes. The symmetry  
 number s in the symmetry code s_pqr should correspond to the expression
 for s in the CIF. Those expressions can be different for different 
 software packages. E.g. pasting H-bond table data generated with PLATON
 into a CIF generated with SHELXL may raise this ALERT. Manual correction   
 of the symmetry code should be trivial.

PLAT708 Type_1 Test for consistency of H-Bond D-H..A Angles and Coordinates in CIF
 Hydrogen-Bond Angle D-H..A listed in the CIF is checked. Alerts are set at 
 1,2 and 3 sigma deviation levels.  
 This ALERT is generally related to incorrect symmetry codes. The symmetry  
 number s in the symmetry code s_pqr should correspond to the expression
 for s in the CIF. Those expressions can be different for different 
 software packages. E.g. pasting H-bond table data generated with PLATON
 into a CIF generated with SHELXL may raise this ALERT. Manual correction   
 of the symmetry code should be trivial.

PLAT710 Type_4 Test for Linear Torsions in CIF
 Torsion angles specified in the CIF are checked for the
 'linear variety' where one or both of the 1-2-3 and 2-3-4 bond 
 angles are close to 180 Deg. SHELXL97 will generate those 'torsions' for   
 molecules containing linear moieties (E.g. Metal-C=O). 

PLAT711 Type_1 Test for label problems for Bonds in CIF
 When labels are found on geometry items (bonds, angles etc.) that are not in   
 the coordinate list, and alert _71n is issued, related to alert _70n.  

PLAT712 Type_1 Test for label problem for Angles in CIF
 When labels are found on geometry items (bonds, angles etc.) that are not in   
 the coordinate list, and alert _71n is issued, related to alert _70n.  

PLAT713 Type_1 Test for label problem for Torsions in CIF
 When labels are found on geometry items (bonds, angles etc.) that are not in   
 the coordinate list, and alert _71n is issued, related to alert _70n.  

PLAT714 Type_1 Test for label problem for Contact Distances in CIF
 When labels are found on geometry items (bonds, angles etc.) that are not in   
 the coordinate list, and alert _71n is issued, related to alert _70n.  

PLAT715 Type_1 Test for label problem for H-Bond D-H distances in CIF
 When labels are found on geometry items (bonds, angles etc.) that are not in   
 the coordinate list, and alert _71n is issued, related to alert _70n.  

PLAT716 Type_1 Test for label problem for H-Bond H..A Distances in CIF
 When labels are found on geometry items (bonds, angles etc.) that are not in   
 the coordinate list, and alert _71n is issued, related to alert _70n.  

PLAT717 Type_1 Test for label problem for H-Bond D..A Distances in CIF
 When labels are found on geometry items (bonds, angles etc.) that are not in   
 the coordinate list, and alert _71n is issued, related to alert _70n.  

PLAT718 Type_1 Test for label problem for H-Bond D-H..A Angles in CIF
 When labels are found on geometry items (bonds, angles etc.) that are not in   
 the coordinate list, and alert _71n is issued, related to alert _70n.  

PLAT720 Type_4 Test for Unusual Labels
 Up to 4 Character Labels of the type C11, H101, N10A, i.e. chemical symbol +   
 number + optional letter are to be preferred.  

PLAT721 Type_1 Test for consistency of Bonds and Coordinates in CIF
 Same as 701 but for distance without s.u. (esd). Difference is tested in terms 
 of Angstroms.  

PLAT722 Type_1 Test for consistency of Angles and Coordinates in CIF
 Same as 702 but for angle without s.u. (esd). Difference is tested in terms of 
 Degrees.   

PLAT723 Type_1 Test for consistency of Torsions and Coordinates in CIF
 Same as 703 but for torsion without s.u. (esd). Difference is tested in terms  
 of Degrees.

PLAT724 Type_2 Test for consistency of Contact Distances and Coordinates in CIF
 Same as 704, but for distance without s.u. (esd). Difference is tested in  
 terms of Angstroms.

PLAT725 Type_2 Test for consistency of H-Bond D-H distances and Coordinates in CIF
 Same as 705 but for distance without s.u. (esd). Differences are tested in 
 terms of Angstrom. 

PLAT726 Type_2 Test for consistency of H-Bond H..A Distances and Coordinates in CIF
 Same as 706 but for distance without s.u. (esd). Differences are tested in 
 terms of Angstrom. 

PLAT727 Type_1 Test for consistency of H-Bond D..A Distances and Coordinates in CIF
 Same as 707 but for distance without s.u. (esd). Differences are tested in 
 terms of Angstrom. 

PLAT728 Type_1 Test for consistency of H-Bond D-H..A Angles and Coordinates in CIF
 Same as ALERT 708 but for angle without s.u. (esd). Differences are tested 
 in terms of Degrees.   

PLAT731 Type_1 Test for consistency of Bond s.u.'s and Coordinate s.u.'s in CIF
 A large ratio of the reported and calculated bond s.u.'s is found. 
 The use of a DFIX instruction might cause such a warning since 
 calculated s.u.'s are based on reported variances only.
 Note_1: s.u.'s on the unit-cell dimensions are taken into account in the   
 calculation of expected s.u.'s. This may result in large differences   
 between expected and reported s.u.'s when this contribution is not included
 in the reported s.u.'s, in particular for inaccurate unit-cells.   
 Note_2: Another source for the discrepancy between calculated and  
 reported s.u.'s can be that the validation software has access only to 
 the variances of the refined parameters as opposed to the full co-variance 
 matrix used by e.g. SHELXL for the calculation of derived parameters   
 with associated s.u.'s. Constrained/restrained refinement may cause large  
 co-variances.  

PLAT732 Type_1 Test for consistency of Angles and Coordinates in CIF s.u.'s
 A large ratio of the reported and calculated bond angle s.u.'s is found.   
 This check should warn for erroneous rounding: E.g. 105.5(19) to 105.5(2) or   
 105.0(5) to 105(5) etc. Note: Large differences are possible when certain  
 constraints/restraints were applied in the refinement (e.g. the FLAT option
 in SHELXL97).  
 Note_1: s.u.'s on the unit-cell dimensions are taken into account in the   
 calculation of expected s.u.'s. This may result in large differences   
 between expected and reported s.u.'s when this contribution is not included
 in the reported s.u.'s, in particular for inaccurate unit-cells.   
 Note_2: Another source for the discrepancy between calculated and  
 reported s.u.'s can be that the validation software has access only to 
 the variances of the refined parameters as opposed to the full co-variance 
 matrix used by e.g. SHELXL for the calculation of derived parameters   
 with associated s.u.'s. Constrained/restrained refinement may cause large  
 co-variances.  

PLAT733 Type_1 Test for consistency of Torsions and Coordinates in CIF s.u's
 A large ratio of the reported and calculated torsion angle s.u.'s is found.
 This check should warn for erroneous rounding: E.g. 105.5(19) to 105.5(2)  
 or 105.0(5) to 105(5) etc. 
 Note_1: s.u.'s on the unit-cell dimensions are taken into account in the   
 calculation of expected s.u.'s. This may result in large differences   
 between expected and reported s.u.'s when this contribution is not included
 in the reported s.u.'s, in particular for inaccurate unit-cells.   
 Note_2: Another source for the discrepancy between calculated and  
 reported s.u.'s can be that the validation software has access only to 
 the variances of the refined parameters as opposed to the full co-variance 
 matrix used by e.g. SHELXL for the calculation of derived parameters   
 with associated s.u.'s. Constrained/restrained refinement may cause large  
 co-variances.  

PLAT734 Type_1 Test for consistency of Contact Distance s.u. and Coordinate s.u. in CIF
 A large ratio of the reported and calculated contact distance s.u.'s is found. 
 Note: s.u.'s on the unit-cell dimensions are taken into account in the 
 calculation of expected s.u.'s. This may result in large differences   
 between expected and reported s.u.'s when this contribution is not included
 in the reported s.u.'s, in particular for inaccurate unit-cells.   

PLAT735 Type_1 Test for consistency of H-Bond D-H distance s.u. and Coordinate s.u in CIF
 A large ratio of the reported and calculated H-bond D-H distance s.u.'s is 
 found. The use of a DFIX instruction might cause such a warning since  
 calculated s.u.'s are based on reported variances only.
 Note: s.u.'s on the unit-cell dimensions are taken into account in the 
 calculation of expected s.u.'s. This may result in large differences   
 between expected and reported s.u.'s when this contribution is not included
 in the reported s.u.'s, in particular for inaccurate unit-cells.   

PLAT736 Type_1 Test for consistency of H-Bond H..A Distance s.u. and Coordinates in CIF
 A large ratio of the reported and calculated H-bond H..A distance s.u.'s   
 is found.  
 Note: s.u.'s on the unit-cell dimensions are taken into account in the 
 calculation of expected s.u.'s. This may result in large differences   
 between expected and reported s.u.'s when this contribution is not included
 in the reported s.u.'s, in particular for inaccurate unit-cells.   

PLAT737 Type_1 Test for consistency of H-Bond D..A Distance s.u. and Coordinates in CIF
 A large ratio of the reported and calculated H-Bond D...A distance s.u.'s is   
 found. 

PLAT738 Type_1 Test for consistency of H-Bond D-H..A Angle and Coordinates in CIF s.u.
 A large ratio of the reported and calculated H-Bond D-H..A angle s.u.'s
 is found.  
 Note: s.u.'s on the unit-cell dimensions are taken into account in the 
 calculation of expected s.u.'s. This may result in large differences   
 between expected and reported s.u.'s when this contribution is not included
 in the reported s.u.'s, in particular for inaccurate unit-cells.   

PLAT741 Type_1 Test for missing Bond s.u. in CIF
 Likely Missing s.u. on Bond in CIF.

PLAT742 Type_1 Test for missing Angle s.u. in CIF
 Likely Missing s.u. on Bond angle in CIF.  

PLAT743 Type_1 Test for missing Torsion s.u. in CIF
 Likely Missing s.u. on Torsion angle in CIF.   

PLAT744 Type_1 Test for missing Contact Distance s.u. in CIF
 Likely missing s.u. on contact Distance in CIF.

PLAT745 Type_1 Test for missing H-Bond D-H distance s.u. in CIF
 Likely missing s.u. on H-Bond D-H distance in CIF. 

PLAT746 Type_1 Test for missing H-Bond H..A Distance s.u. in CIF
 Likely missing s.u. on H-Bond H...A distance in CIF.   

PLAT747 Type_1 Test for missing H-Bond D..A Distance s.u. in CIF
 Likely missing s.u. on H-Bond D...A distance in CIF.   

PLAT748 Type_1 Test for missing H-Bond D-H..A Angle s.u. in CIF
 Likely missing s.u. on H-Bond D-H..A angle in CIF. 

PLAT751 Type_4 Test for senseless Bond s.u. in CIF
 An s.u. should not be given in the CIF for constrained distances.  
 Please check for proper refinement status flags (e.g. R)   

PLAT752 Type_4 Test for senseless Angle s.u. in CIF
 An s.u. should not be given in the CIF for constrained angles. 
 Please check for proper refinement status flags (e.g. R)   

PLAT753 Type_4 Test for senseless Torsion s.u. in CIF
 An s.u. should not be given in the CIF for constrained torsion angles. 
 Please check for proper refinement status flags (e.g. R)   

PLAT754 Type_4 Test for senseless Contact Distance s.u. in CIF
 An s.u. should not be given in the CIF for constrained contact distances.  
 Please check for proper refinement status flags (e.g. R)   

PLAT755 Type_4 Test for senseless H-Bond D-H distance s.u. in CIF
 An s.u. should not be given in the CIF for constrained distances.  
 Please check for proper refinement status flags (e.g. R)   

PLAT756 Type_4 Test for senseless H-Bond H..A Distance s.u. in CIF
 An s.u. should not be given in the CIF for constrained distances.  
 Please check for proper refinement status flags (e.g. R)   

PLAT757 Type_4 Test for senseless H-Bond D..A Distance s.u. in CIF
 An s.u. should not be given in the CIF for constrained distances.  
 Please check for proper refinement status flags (e.g. R)   

PLAT758 Type_4 Test for Senseless H-Bond D-H..A Angle s.u. in CIF
 An s.u. should not be given in the CIF for constrained angles. 
 Please check for proper refinement status flags (e.g. R)   

PLAT761 Type_1 Test for the presence of at least one X-H in the CIF
 The CIF contains no X-H Bonds. This might be caused by not using the   
 SHELXL instruction BOND $H. Inclusion is required by Acta Cryst. but not   
 necessarily so by other journals.  

PLAT762 Type_1 Test for at least one X-Y-H or H-Y-H entry in the CIF
 The CIF contains no X-Y-H or H-Y-H bond angles. This might be caused by not
 using the SHELXL instruction BOND $H. Those data should also be supplied   
 when H-atoms are introduced on calculated positions and/or refined riding  
 on their carrier atom. 
 Inclusion is required by Acta Cryst. but not necessarily so by other journals. 

PLAT763 Type_1 Test for missing bonds in CIF
 Bond list in CIF likely incomplete.

PLAT764 Type_4 Test for overcomplete bonds in CIF
 The CIF contains more bonds than the unique set, indicating redundancy.
 An example is redundancy due to the inclusion of symmetry related bonds.   

PLAT770 Type_2 Test for suspect C-H bonds in CIF (Not caught otherwise)
 Report on unusual C-H bonds not caught in other tests. 

PLAT771 Type_2 Test for suspect N-H bonds in CIF (Not caught otherwise)
 Report on unusual N-H bonds not caught in other tests. 

PLAT772 Type_2 Test for suspect O-H bonds in CIF (Not caught otherwise)
 Report on unusual O-H bonds not caught in other tests. 
 Note: Exceptions can be H-atoms in acid O..H..O bridges or in H5O2+
       (Hydronium) species. 

PLAT773 Type_2 Test for suspect C-C bonds in CIF (Not caught otherwise)
 Report on unusual C-C bonds, possibly  not caught in other tests.  
 Exceptions include C-C distances of around 1.75 Ang. in e.g.   
 1,2-dicarba-closo-dodecaborane.

PLAT774 Type_1 Test for too large / erroneous bond distance
 Likely Erroneous Bond Entry.   

PLAT775 Type_1 Test for too large / erroneous Contact distance
 Likely Erroneous Contact Entry.

PLAT776 Type_1 Test for too large / erroneous H-Bond D-H distance
 Likely Erroneous D-H Entry.

PLAT779 Type_4 Test for suspect Angle in CIF (Not caught otherwise)
 Possibly erroneous (Bond)angle less than 45 degree. The angle might be 
 considered for elimination from the CIF when irrelevant. This ALERT can
 also be triggered when the assigned occupancy factors are incorrect.   

PLAT780 Type_1 Test whether coordinates form a connected set
 Atoms given in a CIF should form a 'connected set', i.e. no symmetry   
 operations are needed to get atoms in a bonding position. A connected set of   
 atoms is not needed for the least squares refinement (unless hydrogen atoms
 are to be added at calculated positions). Geometry listings (bonds, angles,
 torsions & H-bonds) become unwieldy for non-connected atom sets.   

PLAT781 Type_1 Test for Flack x value for Centrosymmetric space-group
 A Flack parameter value is erroneously given for a structure reported  
 in a centrosymmetric space-group.  

PLAT782 Type_2 Test for Unusual C-NO2 an C-CO2 moiety Bond geometry
 Warning for a possible misassignment of C-NO2 and C-CO2 moieties.  
 The geometry of the reported moiety appears to be unusual/inconsistent.
 The C-O bond distances in C-CO2 are expected to add up to about 2.5
 Test Criteria: ALERT for C-O bond sum < 2.48 and C-C < 1.48 Angstrom   
 The N-O bond distances in C-NO2 are expected to add up to about 2.4
 Test Criteria: ALERT for N-O bond sum > 2.48 and C-C > 1.48 Angstrom   

PLAT789 Type_4 Report the number of atoms with negative _atom_site_disorder_group #
 A negative value of the _atom_site_disorder_group number of an atom indicates  
 whether that atom is part of a group disordered over a symmetry element.   
 Check whether this negative sign assignment applies.   

PLAT790 Type_4 Test Whether C.G. Residue in Unitcell Box
 Unless for a good reason, molecular species should be transformed  
 (by symmetry and/or translation) so that their centres of gravity  
 are close to or within the unit-cell bounds. This is a strict rule for the 
 main species. Deviations from this general rule are for smaller additional 
 species when relevant for intermolecular interactions with the main species.   

PLAT791 Type_4 Check the absolute configuration of chiral atom in 'chiral' spgr
 This test addresses the consistency of the absolute configuration  
 assignment in a non-centrosymmetric structure with proper symmetry  
 operations only (i.e. all matrices with determinant = 1).
 The correct R/S assignment depends on the algorithm used to automatically
 detect double and triple bonds.   
 Verify the (R/S) absolute configuration assignment of this atom and
 the consistency of the absolute configuration implicit in the CIF-data 
 with that in the 'ORTEP' illustration. Torsion angles should have the  
 correct sign.  
 The absolute structure assignment should also be consistent with the   
 lowest value of the Flack parameter and/or known absolute configuration.

PLAT792 Type_1 Check the absolute configuration of chiral atom in 'non-chiral' spgr
 This test addresses the consistency of the absolute structure assignment   
 (i.e. polarity etc.) in non-centrosymmetric structures in space groups 
 that include improper symmetry operations (e.g. mirror planes).
 Check the (R/S) absolute configuration assignment of this atom and 
 the consistency of the absolute configuration implicit in the CIF-data 
 with that in the 'ORTEP' illustration. 

PLAT793 Type_4 Check the absolute configuration of chiral atom in centrosymmetric spgr
 This test addresses the consistency of the absolute configuration assignment   
 of molecules in the reported asymmetric unit among coordinates,
 molecular presentations and chemical diagrams. 
 Check the (R/S) absolute configuration assignment of this atom and 
 the consistency of the absolute configuration implicit in the CIF-data 
 with that in the 'ORTEP' illustration. 

PLAT794 Type_5 Report the calculated 'Valence Bond' valency for metals
 This test reports the valency of an atom as predicted by the Valence   
 Bond Model. See:   
 N.E. Brese & M. O'Keeffe (1991) Acta Cryst. B47, 192-197.  
 I.D. Brown (2002). The Chemical Bond in Inorganic Chemistry:   
      The Bond Valence Model. Oxford University Press.  
 More explicit info on the calculations can be obtained by running the  
 calculations explicitly with the PLATON option BondValence.
 Note: The underlying theory is empirical and might not apply to the
       case at hand (e.g. charged species). 

PLAT798 Type_4 Test for Alphanumeric Label on coordinate record
 Atom labels are generally not a number (i.e. starting with one or two  
 characters indicating the atom type). Labels can be erroneously numeric
 due to typing errors (e.g. 'Oxygen' typed as 'zero').  

PLAT799 Type_4 Test for Alphanumeric Label on displacement par. record
 Atom labels are generally not a number (i.e. starting with one or two  
 characters indicating the atom type). Labels can be erroneously numeric
 due to typing errors (e.g. 'Oxygen' typed as 'zero').  

PLAT801 Type_4 Test for missing, incomplete or out-of-order Cell data
 PLATON/CheckCIF has a problem with the Cell data. A possible reason can be 
 that the cell data are missing, incomplete or out-of-sequence. 
 PLATON/CheckCIF wishes to encounter the cell and symmetry data before any  
 coordinates are given. PLATON expects the values of all six cell parameters.   

PLAT802 Type_4 Test for Input lines longer than 80 Characters
 The CIF contains records longer than 80 characters. Not all software will  
 read beyond column 80. 
 The CIF-1.1 definition specifies a maximum of 2048 character per record.   

PLAT803 Type_1 Test for Loop problem in CIF-Read
 Fatal Problem: Check loop data names and data for errors. There are
 likely too many or to few data in the loop.

PLAT804 Type_5 Test for ARU-Pack Problem(s) in PLATON
 Problem: ARU representations turn out to be needed outside the ORTEP   
 style -5:5 unit-cell translation range. The Analysis might be incomplete.  
 The problem often occurs for structures with aliphatic chains stretching   
 over many unitcells or network structures. Transformation of the unitcell  
 content to a symmetry related position might solve the problem.

PLAT805 Type_1 Test for insufficient 'coordinate data'
 Check Coordinate Data Loop.

PLAT806 Type_4 Test for insufficient 'UIJ data'
 Check UIJ Data Loop.   

PLAT807 Type_5 Test for Maximum number of ATOMS Exceeded Problem
 PLATON can handle up to 'NP1' in the (expanded) ATOM list. 
 This might happen with disordered or network structures in high
 symmetry space groups. Deletion of the symmetry information might solve
 part of the problem and provide a partial validation.  
 Alternatively, clicking on 'NOSYMM' on the PLATON menu before invoking 
 validation might address the problem.  

PLAT808 Type_5 Test for Parseable SHELXL style Weighting scheme
 The software did not succeed in finding/analyzing a parsable weighting 
 scheme.
 SHELXL style weight parameters are expected to be given in the format: 
 _refine_ls_weighting_details   
 'calc w=1/[\s^2^(Fo^2^)+(0.1000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
 JANA style weight is expected to be given in the format:   
 _refine_ls_weighting_details 'w=1/(\s^2^(I)+0.0016I^2^)'   
  Do not edit this string or make it into a text block between ';'. 

PLAT809 Type_1 Test the SHELXL style Weighting scheme
 The software did not succeed in Parsing the SHELXL style weighting 
 scheme. The string might have been edited or of the more than 2 parameter  
 variety (see SHELXL manual).   

PLAT810 Type_5 Test for Out-of-Memory Problem
 Analysis for missing reflections may be incomplete due to an out-of-memory 
 problem.   

PLAT811 Type_5 Test for No ADDSYM Analysis
 The ADDSYM test for missed symmetry is not executed for structures with too
 many disordered atoms. 

PLAT812 Type_5 Test for ALIAS OVERFLOW
 Non-standard labels are aliased into acceptable labels. The maximum number 
 of aliases is reached. 

PLAT813 Type_1 Test for insufficient data on HKLF record in CIF
 Check the HKLF record in the SHELXL style .res is embedded in the CIF. 
 This Record should show either 'HKLF 4' or 'HKLF 5'.   
 The information in this record is used to establish that a twinning model  
 was refined.   

PLAT814 Type_5 Test fot (In)Commensurate Structure CIF
 PLATON/CheckCIF can not validate the CIFs associated with (in)commensurate 
 structure reports. 

PLAT820 Type_5 Report Read Problem in PLATON/PLA230
 Internal PLATON Problem. Please refer problem to author at a.l.spek@uu.nl  

PLAT850 Type_4 Test for BASF/TWIN Problem in SHELXL
 This G_ALERT can be ignored in the case that the so-called 'on-the-cheap'  
 Flack parameter is reported as determined with SHELXL. 
 Exactly zero values are possible but may also be a software artefact.  
 The following should be checked:   
 Problem #1: Some SHELXL97 versions do not allow negative values of the 
 Flack parameter when determined using the BASF/TWIN instructions.  
 Negative values are set to 0.00001. Refinement may not converge completely.
 Problem #2: Some SHELXL97 versions put meaningless values in the CIF for the   
 Flack parameter when 'TWIN -1 0 0 0 -1 0 0 0 -1 2 / BASF' instructions (i.e.   
 an explicit matrix is specified on the TWIN instruction) are used. 
 Please check the value of BASF (in the list output)  against the Flack 
 parameter in the CIF. 	

PLAT860 Type_3 Test for restraints used in refinement
 The use of restraints used in the refinement should be explained in
 the write-up of a structure analysis.  
 It is also recommended to include the refinement instructions in the   
 CIF (e.g. the final .res of a SHELXL refinement) as a comment: 
 _iucr_refine_instructions_details  
 ;  
 TITL   
 .. 
 (etc.) 
 ;  
 Note: An exception are restraints for floating origins (e.g. in P21).  

PLAT868 Type_4 Report the Suppression of Olex2/_smtbx_masks use Related ALERTS
 ALERTS related to the use of Olex2/_smtbx_masks that can not (yet) be  
 accounted for as part of the VALIDATION algorithms have been suppressed.   

PLAT869 Type_4 Report the Suppression of SQUEEZE use Related ALERTS
 ALERTS related to the use of PLATON/SQUEEZE that can not (yet) be accounted
 for as part of the VALIDATION algorithms have been suppressed. 

PLAT870 Type_4 Report the Suppression of some Twinning Related ALERTS
 ALERTS related to twinning effects that can not (yet) be accounted 
 for as part of the VALIDATION algorithms have been suppressed. 

PLAT871 Type_4 Report the Suppression of some Laue technique related ALERTS
 ALERTS related to the use of the Laue technique with a wavelength  
 range have been suppressed.

PLAT880 Type_1 Report missing datum for _diffrn_reflns_number
 The total number of measured reflections is not reported.  

PLAT881 Type_1 Report missing datum for _diffrn_reflns_av_R_equivalents
 The merging R-factor for equivalent reflections is missing in the CIF. 
 A value of 0.0 usually indicates that merging has been done outside the
 program that created the CIF. A proper value should be included as reported
 by the external merging program. Note: modern hardware will generally produce  
 redundant reflection data. 

PLAT882 Type_1 Report missing datum for __diffrn_reflns_av_unetI/netI
 No value reported for either _diffrn_reflns_av_unetI/netI or the   
 older/superseded _diffrn_reflns_av_sigmaI/netI CIF item.   

PLAT883 Type_1 Report missing datum for _atom_sites_solution_primary
 Please supply the proper info for _atom_site_solution_primary. Values must
 be one of the following: difmap, vecmap, heavy, direct, geom, disper, isomor,
 notdet, dual, iterative, other.

PLAT898 Type_4 Check for duplicate H-M space group symbol
 A second specification of the H-M symbol is found in the CIF. Only the 
 first one encountered is retained. 

PLAT899 Type_4 Report the Use of an older SHELXL version
 A more recent SHELXL version is now available. Final refinement with the   
 latest version is recommended. 

PLAT900 Type_1 Test for 'No-matching reflection file'
 Likely cause: Dataset names in the CIF and FCF differ. 
 Note: FCF Validation is Skipped for this Entry.

PLAT901 Type_1 Test for CIF & FCF CELL Not Matching
 Possible causes: wrong dataset, CIF or FCF parameters edited inconsistently
 or cell parameters for transformed cell (e.g. P21/n <-> P21/c).
 Note: FCF Validation is Skipped for this Entry.

PLAT902 Type_1 Test for non-zero number of recognised reflections in FCF
 Either no reflections are found in the FCF or the FCF is uninterpretable   
 due to unknown format or editing.  
 Note: FCF Validation is Skipped for this Entry.

PLAT903 Type_1 Test for Fobs=Fcalc in FCF
 Check the FCF file for F(obs) equal F(calc) [of F(obs)**2 equal F(calc)**2].   

PLAT904 Type_1 Test for NREF .GT. NPAR in the CIF
 The number of reflections found in the reflection file is less than
 the number of parameters reported in the CIF.  

PLAT905 Type_3 Report Negative K values in the Analysis of Variance
 Scale Factors (i.e. K = Mean[Fo**2] / Mean [Fc**2]) for selected groups of 
 reflections, as listed in the Analysis of Variance Section #7 of the FCF   
 validation report, are expected to have a value of about 1.000. Strong 
 deviations should be investigated, acted upon or explained.
 (see also SHELXL manual). A reason can be meaningless (weak) high order
 data where a cut-back of the resolution might be indicated. Incorrect  
 background treatment can lead to numerous negative observed intensities
 for weak reflections (i.e. F(calc) close to zero.  
 For details see the Analysis-of-Variance Section in the '.ckf' file.   

PLAT906 Type_3 Report Large K values in the Analysis of Variance
 Scale Factors (i.e. K = Mean[Fo**2] / Mean [Fc**2]) for selected groups of 
 reflections, as listed in the Analysis of Variance Section #7 of the FCF   
 validation report, are expected to have a value of about 1.000. Strong 
 deviations should be investigated, acted upon or explained.
 (see also SHELX manual).   
 For details see the Analysis-of-Variance Section in the '.ckf' file.   

PLAT907 Type_2 Check whether the structure needs to be inverted
 A Flack x value generally indicates that the structure needs to be inverted.   
 Check whether the Flack x value is unreliable due to weak anomalous
 dispersion signal, systematic errors or weak data and against know absolute
 structure. 

PLAT908 Type_2 Report on Max Observed data in any Resolution Shell
 A low maximum percentage of reflections with I > 2*s(I) may indicate:  
 1 - Missed translation symmetry. E.g. all reflections hkl weak 
     for l = 2n +1  
 2 - Pseudo-merohedral twinning, index > 1. (e.g. non-spacegroup
     extinctions.   
 3 - Very weak observed data.   

PLAT909 Type_3 Report of Observed data at Theta Cutoff
 This ALERT Reports on whether there is still a significant level of
 observed data beyond the Theta cutoff of the Dataset. There should 
 be a good reason for a cutoff below sin(theta)/lambda = 0.6.   
 Reflection data beyond that value should not be removed when significantly
 above the noise level. E.g. they may be very relevant in case of pseudo-
 symmetry and (non)centrosymmetry refinement. 

PLAT910 Type_3 Test for missing reflections below Theta(Min)
 Possible causes: Beamstop Theta(min) limit set too high, large unit-cell etc.  
 A possible technical solution on CCD based equipment involves the collection   
 of additional images with the detector at a larger distance from the   
 crystal with the beamstop setting changed accordingly..
 Alternatively, a large number of low-order reflections might have been
 'Omitted' from the (final) least-squares refinement.

PLAT911 Type_3 Test for missing reflections between Theta(Min)and sinth/lambda=0.6
 Possible causes: Missing cusp of data (due to rotation about one axis),
 deleted (overflow) reflections or improper strategy (orthorhombic for  
 monoclinic crystal etc.)   

PLAT912 Type_4 Test for missing reflections above Sin(TH)/Lambda = 0.6
 Possible causes: Missing cusp of data (due to rotation about one axis),
 deleted (overflow) reflections or improper strategy (orthorhombic for  
 monoclinic crystal etc.)   

PLAT913 Type_3 Test for missing strong reflections
 This ALERT reports the number of missing reflections with Fc**2 values 
 greater than the largest Fc**2 value in the FCF.   
 Possible causes: Missing cusp of data (due to rotation about one axis),
 deleted (overflow) reflections or improper strategy (orthorhombic for  
 monoclinic crystal etc.) or behind the beamstop.   

PLAT914 Type_3 Test for absence of Bijvoet Pairs in non-centro structure
 This ALERT reflects the notion that a dataset should contain a sufficient  
 number of Bijvoet (Friedel) pairs for the reliable determination of the
 absolute structure of a non-centrosymmetric crystal structure. 
 This test is invoked when a Flack parameter value is specified.
 Note: SHELXL97 will calculate/report a Flack parameter value even for  
 refinement against Friedel merged data. Remove the Flack entry from the
 CIF.   

PLAT915 Type_3 Test for low Friedel Pair Coverage in non-centro structure
 This ALERT reflects the notion that a dataset should contain a sufficient  
 number of Bijvoet (Friedel) pairs for the reliable determination of the
 absolute structure of a non-centrosymmetric crystal structure. 
 A Friedel coverage that deviates significantly from 100 percent may
 bias/invalidate the value of the Flack parameter.  

PLAT916 Type_2 Test for differing Flack x and Hooft y Parameter values
 The Hooft y Parameter is calculated independently from the Bijvoet 
 differences and should have a value similar (observing the s.u.'s) to that of  
 the Flack x Parameter. 
 See:   
 Hooft, R.W.W, Straver, L.H. & Spek,A.L. (2008). J. Appl, Cryst. 41, 96-103.
 Thompson,A.L. & Watkin, D.J. (2009). Tetrahedron: Asymmetry,   
   doi:10.1016/j.tetasy.2009.02.025 
 Large differences may arise in cases where the Flack parameter was not 
 done with BASF/TWIN or with essentially centrosymmetric data.  
 See:   
 Flack, H.D., Bernardinelli, G, Clemente, D.A., Linden, A. Spek, A.L. (2006)
 Acta Cryst. B62, 695-701.  

PLAT917 Type_2 Test/Report whether FCF is based on a BASF/TWIN refinement
 The contribution of F(-h,-k,-l) to F(h,k,l) is likely not included in the  
 FCF file. This usually indicates that the Flack parameter was NOT determined   
 with a BASF/TWIN type of refinement.   

PLAT918 Type_3 Test for reflections with I(obs) << I(calc)
 This ALERT reports on the number of reflections with   
 (Fo**2 - Fc**2) / Sigma(Fo**2) < - 100.0. In case of strong reflections this   
 might be due to extinction (to be addressed with the refinement of an  
 extinction parameter. Otherwise Those reflections are better removed from  
  the final refinement since they are in systematic error.  
 Of course, a valid reason for this problem should be found.

PLAT919 Type_3 Test for reflections effected by the beamstop
 This ALERT reports the number of reflections with intensities seriously
 effected by the beamstop. Reflections are counted for which theta < 3  
 Degrees and (Fo**2 - Fc**2) / sqrt(weight) < - 10.0. Those reflections 
 are better removed from the final refinement since they are in systematic  
 error. 

PLAT920 Type_1 Test for TH(Max) Consistency between CIF & FCF
 Check reflection statistics of the data in the FCF for consistency with
 the data reported in the CIF.  
 A difference usually indicates an edited CIF or an FCF file that was   
 not created in the same SHELXL run where the CIF was created.  

PLAT921 Type_1 Test for R1 Consistency between CIF & FCF(Reported)
 Please check whether the supplied FCF corresponds with the CIF produced in 
 the same least squares refinement job. 
 See at the end of Section #10 in the .ckf report file for details.
 The test is based on the observed and calculated F**2 in the FCF and de
 weight parameters taken from the CIF.  

PLAT922 Type_1 Test for wR2 Consistency between CIF & FCF(Reported)
 Please check whether the supplied FCF corresponds with the CIF produced in 
 the same least squares refinement job. 
 See at the end of Section #10 in the .ckf report file for details.
 The test is based on the observed and calculated F**2 in the FCF and de
 weight parameters taken from the CIF.  

PLAT923 Type_1 Test for S Consistency between CIF & FCF(Reported)
 Please check whether the supplied FCF corresponds with the CIF produced in 
 the same least squares refinement job. 
 See at the end of Section #10 in the .ckf report file for details.
 The test is based on the observed and calculated F**2 in the FCF and de
 weight parameters taken from the CIF.  

PLAT924 Type_1 Test for Consistency of the Reported & Calculated Rho(min)
 Check & Explain why the Reported Rho(min) differs significantly from   
 the value calculated on the basis of the reported structure.   
 Note: The Reported and Calculated values may differ slightly due to
 a differing peak interpolation algorithm.  

PLAT925 Type_1 Test for Consistency of the Reported & Calculated Rho(max)
 Check & Explain why the Reported Rho(max) differs significantly from   
 the value calculated on the basis of the reported structure.   
 Note: The Reported and Calculated values may differ slightly due to
 a differing peak interpolation algorithm.  

PLAT926 Type_1 Test for R1 Consistency between CIF & FCF(Calculated)
 Please check whether the R1 value that is reported in the CIF corresponds  
 with the R1 value calculated from the parameters supplied in the CIF.
 See at the end of Section #10 in the .ckf report file for details.
 This test is based on the observed reflection data in the FCF and  
 reflection data that are calculated with the parameters (i.e. coordinates, 
 displacement and weight parameters) taken from the CIF.

PLAT927 Type_1 Test for wR2 Consistency between CIF & FCF(Calculated)
 Please check whether the wR2 value that is reported in the CIF corresponds 
 with the wR2 value calculated from the parameters supplied in the CIF. 
 See at the end of Section #10 in the .ckf report file for details.
 This test is based on the observed reflection data in the FCF and  
 reflection data that are calculated with the parameters (i.e. coordinates, 
 displacement and weight parameters) taken from the CIF.

PLAT928 Type_1 Test for S Consistency between CIF & FCF(Calculated)
 Please check whether the S value that is reported in the CIF corresponds   
 with the S value calculated from the parameters supplied in the CIF.   
 See at the end of Section #10 in the .ckf report file for details.
 This test is based on the observed reflection data in the FCF and  
 reflection data that are calculated with the parameters (i.e. coordinates, 
 displacement and weight parameters) taken from the CIF.

PLAT929 Type_5 Test for interpretable weight parameters for R1,wR2 & S Comparison
 SHELXL weight parameters are expected to be given in the format below: 
 _refine_ls_weighting_details   
 'calc w=1/[\s^2^(Fo^2^)+(0.1000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
 JANA style weight is expected to be given in the format:   
 _refine_ls_weighting_details 'w=1/(\s^2^(I)+0.0016I^2^)'   
  Do not edit this string or make it into a text block between ';'. 

PLAT930 Type_2 Test for Missed Twinning from FCF data
 Check the proposed Twin Law. The entry in () represents the proposed   
 rotation axis in reciprocal space and the one in [] the corresponding  
 rotation is direct space.  
 The relevant Twin Matrix can be found in the file '.ckf'.  
 Note: This analysis is based on Fo/Fc differences with Fc data given   
 in the .fcf file (i.e. Fobs, Fcalc listing).   
 ALERT-930 is expected to generate an related ALERT-931 as well.

PLAT931 Type_5 Test for Missed Twinning from FCF/CIF data
 Check the proposed Twin Law. The entry in () represents the proposed   
 rotation axis in reciprocal space and the one in [] the corresponding  
 rotation is direct space.  
 The relevant Twin Matrix can be found in the file '.ckf'.  
 Note: This test is based on F(calc) values calculated with the data
 in the CIF. This ALERT can be ignored when twinning has been addressed 
 in the refinement (As indicated by the Absence of ALERT 930).  
 Please check whether twinning is mentioned in the write-up of the  
 paper. 

PLAT933 Type_2 Report number of OMIT records in embedded .res
 This ALERT reports on the number of OMIT records (Reflections omitted from 
 the least-squares refinement) in the CIF.  

PLAT934 Type_3 Report number of outliers
 This ALERT reports on the number of reflections for which I(obs) and I(calc)   
 differ more that 10 times SigmaW. (The latter being the square root of 
 1.0/weight for that reflection in the L.S. refinement). The reason for those   
 deviations should be investigated. When shown to be systematic errors, 
 those reflections are best removed from the refinement and their omission  
 from the refinement reported in the experimental section of an associated  
 paper. 

PLAT935 Type_2 Pseudo Extinction Parameter Test
 Both significantly positive and significantly negative values should   
 invoke a search for a likely cause and a corrective action.

PLAT936 Type_2 Test for DAMP instruction in embedded .res
 The reason for the use of a DAMP instruction in the final refinement job   
 should be discussed/reported. 'DAMP 0.0' should not be used for small  
 molecule refinement since it masks non-convergence.

PLAT937 Type_4 Report Exponential Term in SHELXL weight expression
 The use of an exponential term in the SHELXL weight expression is not  
 recommended in the final refinement stage (i.e. the third parameter in the 
 SHELXL WGHT record).   

PLAT939 Type_3 Test for high not weight optimized S value
 SHELXL optimizes two weight parameters to bring the S value close to   
 1.0. This ALERT reports the S value based on the supplied sigma(I) 
 only. A large value of the last generally indicates the presence of
 large outliers in the data set. Examples are reflections 'measured'
 behind the beam stop. (See also ALERT_919). The latter are best left   
 out with an OMIT instruction.  

PLAT940 Type_3 Test for wR2 refinement with all data
 Apparently, observed data with I > n * sigma(I) were used in the F**2  
 least squares refinement, rather than all observed data.   

PLAT949 Type_5 Test for Poisson type Intensity Sigma Distribution
 Check the validity of the observed reflection data.

PLAT950 Type_5 Test for Reported and Calculated Hmax Difference (From CIF Data)
 Reported (in the CIF) and Calculated (from Theta-max in CIF) Max(Hmax,-Hmin)   
 values differ by at least one unit. Check the consistency of wavelength and
 reported resolution data items.

PLAT951 Type_5 Test for Reported and Calculated Kmax Difference (From CIF Data)
 Reported (in the CIF) and Calculated (from Theta-max in CIF) Max(Kmax,-Kmin)   
 values differ by at least one unit. Check the consistency of wavelength and
 reported resolution data items.

PLAT952 Type_5 Test for Reported and Calculated Lmax Difference (From CIF Data)
 Reported (in the CIF) and Calculated (from Theta-max in CIF)  Max(Lmax,-Lmin)  
 values differ by at least one unit. Check the consistency of wavelength and
 reported resolution data items.

PLAT953 Type_1 Test for Reported (in CIF) and Actual Hmax Difference in the FCF File
 Reported (in the CIF) and Actual (in the FCF)  Max(Hmax,-Hmin) values  
 differ by more than one unit. Check for data set truncation.   

PLAT954 Type_1 Test for Reported (in CIF) and Actual Kmax Difference in the FCF File
 Reported (in the CIF) and Actual (in the FCF) Max(Kmax,-Kmin) values   
 differ by more than one unit. Check for data set truncation.   

PLAT955 Type_1 Test for Reported (in CIF) and Actual Lmax Difference in the FCF file
 Reported (in the CIF) and Actual (in the FCF) Max(Lmax,-Lmin) values   
 differ by more than one unit. Check for data set truncation.   

PLAT956 Type_1 Test for Calculated (Theta-max) and Actual Hmax Difference in the FCF File
 Calculated (From Theta-Max in the CIF) and Actual (in the FCF) Max(Hmax,-Hmin) 
 values differ by more than one unit. Check for data set truncation.

PLAT957 Type_1 Test for Calculated (Theta-max) and Actual Kmax Difference in the FCF File
 Calculated (From Theta-Max in the CIF) and Actual (in the FCF) Max(Kmax,-Kmin) 
 values differ by more than one unit. Check for data set truncation.

PLAT958 Type_1 Test for Calculated (Theta-max) and Actual Lmax Difference in the FCF file
 Calculated (From Theta-max in the CIF) and Actual (in the FCF) Max(Lmax,-Lmin) 
 values differ by more than one unit. Check for data set truncation.

PLAT960 Type_3 Test for reflections with I < - 2 sigma
 Multiple strongly negative intensities may be indicative for poor  
 integration of the  diffraction images.
 Too many negative intensities may result in higher than usual wR2 values.  

PLAT961 Type_5 Test for absence of negative observed intensities
 Generally, both positive and slightly negative intensities are expected
 in a data set. Resetting negative intensities to zero may bias the 
 refinement results and the 'analysis-of-variance' as reported e.g. in  
 the SHELXL output listing. 

PLAT962 Type_5 Test for Input Reflections with Sig(Fo^2) = 0
 Reflections with Sigma(Fo^2) = 0 are suspect and best left out of the  
 refinement.
 This type of reflections will result in multiple R & S-value difference
 ALERTS.

PLAT963 Type_2 Test for both weighting parameter values zero (SHELXL)
 Check unusual reported/refined zero SHELXL weight parameter values.  
 Note: SHELXL will not refine to negative values.

PLAT970 Type_5 Test/Report Electron Diffraction
 A structure based on electron diffraction is reported. 
 Please check for the use of proper electron scattering factors in the  
 refinement. X-ray scattering factors are not appropriate for a SHELXL based
 refinement.

PLAT971 Type_2 Test for large positive calculated residual density
 Larger than expected residual density maximum outside metal atom locations.
 This might be caused by unaccounted for twinning, wrongly assigned 
 atom types, unaccounted for solvent and other model errors.

PLAT972 Type_2 Test for large negative calculated residual density
 Larger than expected residual density minimum outside metal atom locations.
 This might be caused by unaccounted for twinning, wrongly assigned 
 atom types and other model errors. 

PLAT973 Type_2 Test for large positive density on metal atom
 Larger than expected residual density maximum on metal atom location.  
 This might be caused by unaccounted for twinning, wrongly assigned 
 atom types and other model errors. 
 Another cause may be a SHELXL 'DAMP 0 0' instruction for a non-converged   
 refinement.

PLAT974 Type_2 Test for large negative density close to metal atom
 Larger than expected residual density minimum on metal atom location.  
 This might be caused by unaccounted for twinning, wrongly assigned 
 atom types and other model errors. 
 Another cause may be a SHELXL 'DAMP 0 0' instruction for a non-converged   
 refinement.

PLAT975 Type_2 Test for positive density near N or O
 Positive density found in a difference density map at a position   
 within bonding distance for a hydrogen atom from a nitrogen or oxygen  
 atom.  
 A possible reason can be a missing hydrogen atom.  
 Also check for tautomerism.

PLAT976 Type_2 Test for negative density near N or O
 Negative density found in a difference density map at a location   
 within bonding distance for a hydrogen atom from a nitrogen or oxygen  
 atom.  
 A possible reason can be a misassigned hydrogen atom.  
 Also check for tautomerism.

PLAT977 Type_2 Test for negative density on H-atom positions
 Negative density found in a difference density map at a H-atom location.   
 A reason might be an incorrect AFIX instruction.   

PLAT978 Type_2 Report number of cases with positive density on C-C bonds
 Difference density maps generally show residual densities on C-C bonds.
 A significant number may indicate good data.   
 Cases where this number is zero should be investigated for a reason.   

PLAT980 Type_1 Test for non-zero number of anomalous scattering factors
 Check for missing anomalous scattering factors.

PLAT981 Type_1 Test for non-zero f" anomalous scattering factor values
 Check for non-zero f" anomalous scattering factor values in the CIF.   
 Note: Zero values are correct for SHELXL MERG 4 refinements.   

PLAT982 Type_1 Test the anomalous scattering factor f' values against IT
 Check the supplied anomalous scattering factor f' value against those  
 in the International Tables.   

PLAT983 Type_1 Test the anomalous scattering factor f" values against IT
 Check the supplied anomalous scattering factor f'' value against those 
 in the International Tables.   

PLAT984 Type_1 Test the anomalous scattering factor f' values against B&C
 Check the supplied anomalous scattering factor f' value for the
 non Cu, Mo, or Ag wavelength against those of Brennan & Cowan. 

PLAT985 Type_1 Test the anomalous scattering factor f" values against B&C
 Check the supplied anomalous scattering factor f'' value for the   
 non Cu, Mo, Ag wavelength against those of Brennan & Cowan.

PLAT986 Type_1 Test for non-zero f' anomalous scattering factor values
 Check for non-zero f' anomalous scattering factor values in the CIF.   

PLAT987 Type_1 Test for the need of a TWIN/BASF refinement
 A BASF/TWIN refinement of the Flack x parameter is indicated when its value
 deviates significantly from zero as measured against its associated s.u. value.
 This applies in particular for structures containing significant anomalous 
 scatterers.
 With a default SHELXL refinement, the Flack x parameter value is not   
 taken into account in the refinement model as part of the calculation of   
 F(calc) and the creation of the FCF file.  
 Inclusion of a Flack x in the refinement model that deviates significantly 
 from zero will lead to lower R-values and a better model.  

PLAT988 Type_1 Report the use of supplied f' for missing internaly calculated value
 Check the supplied anomalous scattering factor f' value for the
 reported wavelength. (No internally calculated value available).   

PLAT989 Type_1 Report the use of supplied f'' for missing internaly calculated value
 Check the supplied anomalous scattering factor f'' value for the   
 reported wavelength. (No internally calculated value available).   

PLAT990 Type_1 Report Deprecated .res file based SQUEEZE job
 SQUEEZE jobs should as of the availability of SHELXL20xy be based on the   
 use of a CIF+FCF created in a SHELXL20xy refinement.   
 See A.L.Spek (2015) Acta Cryst. C71, 9-18. 

PLAT991 Type_5 Report on generated hkl data
 Warning that the reflection data are not experimental.

PLAT992 Type_5 Report difference between reported and actual _reflns_number_gt values
 
 CIF Reported and actual (in FCF) '_reflns_number_gt' values are found to
 differ.  

PLAT993 Type_1 Report Missing .bodd Include File
 The CIF-embedded .res file includes a call for a .bodd include file. Such a
 file is not found externally or CIF-embedded. Without this file, the 
 details of the refinement are not complete and no .fcf can be created.

PLAT994 Type_1 Report Missing SHELXL/MERG instruction
 A SHELXL job generally includes a MERG instruction. If not, the refinement 
 and LIST 4 FCF will include redundant reflections (i.e. refinement on more 
 than the unique set of reflections.)   

PLAT996 Type_1 Test validity of SHELXL Style LIST 4 Fo/Fc FCF File
 A SHELXL LIST 4 Style FCF File should comply with the SHELXL Format.   
 This implies that an FCF should include only a unique set of reflections.  
 For non-centrosymmetric structures, Friedel pairs should be included.  

PLAT997 Type_1 Test for Acceptable CIF/FCF file Combination for SHELXL
 The CIF file reports refinement with SHELXL whereas the supplied reflection
 file is not of the SHELXL LIST 4 or LIST 8 type.   
 Proper FCF validation is not possible with the alternative LIST options.   

PLAT998 Type_1 Test for LIST3
 IUCr CheckCIF validation requires SHELXL/LIST 4, LIST 8 or Equivalent  
 Fo**2,Fc**2, sigma(Fo**2)  reflection files.   

PLAT999 Type_1 Test for LIST6
 IUCr CheckCIF validation requires SHELXL/LIST 4, LIST 8 or Equivalent  
 Fo**2,Fc**2, sigma(Fo**2)  reflection files.   


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