(IUCr) Crystallography Journals Online checkcif report

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Acta Cryst. (2004). E60, m1513-m1515 [ doi:10.1107/S1600536804023487 ]

Bis(benzyltrimethylammonium) tetrachloronickelate(II) N-methylpyrrolidin-2-one solvate

H. Kooijman, M. A. Keegstra, L. Brandsma and A. L. Spek

Online 30 September 2004

Key indicators

Single-crystal X-ray study
T = 298 K
Mean (C-C) = 0.014 Å
R factor = 0.069
wR factor = 0.182
Data-to-parameter ratio = 15.6

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT027_ALERT_3_A _diffrn_reflns_theta_full (too) Low ............      24.24 Deg.

Author Response:

 The available crystals of the title compound diffracted very weakly,
 especially at higher diffraction angles. This is most likely related
 to the disorder in the solvent molecule and the fact that the crystals
 are thin plates, which contain only a limited amount of matter (see
 also our response to _vrf_PLAT063_I). Data were collected in shells of
 increasing diffraction angle. In the shell with 0.52 < sin\q/\l < 0.55
 [i.e. 21.7 < \q < 23.0 deg] 24.6% of the reflections had an intensity
 of at least twice its standard uncertainty. In the next shell, with
 0.55 < sin\q/\l < 0.58, [i.e. 23.0 < \q < 24.3 deg] only 13.6% of the
 reflections had an intensity above this level. Data collection was
 therefore terminated after finishing this shell.

 Validation issues a number of other alerts which are related to this
 issue:
THETM01_ALERT_3_C  The value of sine(theta_max)/wavelength is less than 0.590
             Calculated sin(theta_max)/wavelength =    0.5777;
PLAT023_ALERT_3_C Resolution (too) Low [sin(th)/Lambda < 0.6]..... 24.24 Deg.;
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....   48 Perc.;
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......
 0.98.

PLAT063_ALERT_3_A Crystal Probably too Large for Beam Size .......       1.25 mm

Author Response:

 Crystals of the title compound are very thin plates, which diffracted
 weakly (see also _vrf_PLAT027_I). A large crystal was used in order to
 gain some intensity. The diffractometer, using \b-filtered MoK\a
 radiation, was equipped with a wide collimator (approximately 2 mm) to
 ensure that the whole crystal was irradiated by the homogenous part of
 the X-ray beam. The vertical aperture at the point detector was set to
 6 mm, the horizontal aperture to 3.81 mm. With these settings, the
 detector receives the diffracted beam without cutting off any edges.

 This alert is related to the following level B alert, which was also
 issued during validation:
CRYSS02_ALERT_3_B  The value of _exptl_crystal_size_max is > 1.0
    Maximum crystal size given =   1.250


Alert level B
CRYSS02_ALERT_3_B  The value of _exptl_crystal_size_max is > 1.0
   Maximum crystal size given =   1.250
PLAT201_ALERT_2_B Isotropic non-H Atoms in Main Residue(s) .......          3       

Alert level C
THETM01_ALERT_3_C  The value of sine(theta_max)/wavelength is less than 0.590
            Calculated sin(theta_max)/wavelength =    0.5777
PLAT023_ALERT_3_C Resolution (too) Low [sin(th)/Lambda < 0.6].....      24.24 Deg.  
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         48 Perc. 
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.98       
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT241_ALERT_2_C Check High   U(eq) as Compared to Neighbors  for        C21     
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors  for         N1     
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors  for         N2     
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors  for        C16     
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors  for         N3     
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors  for        Ni1     
PLAT301_ALERT_3_C Main Residue  Disorder .........................       8.00 Perc. 
PLAT341_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...         14       

   2 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
  13 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   7 ALERT type 2 Indicator that the structure model may be wrong or deficient
   9 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion