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Acta Cryst. (2013). E69, o1216-o1217  [ doi:10.1107/S1600536813018230 ]

Bis(1,3-dimethyl-1H-imidazolium) hexafluorosilicate methanol 0.33-solvate

C. Tian, W. Nie and M. V. Borzov


Key indicators

checkCIF/PLATON results

No syntax errors found




Alert level C PLAT041_ALERT_1_C Calc. and Reported SumFormula Strings Differ ? Check
Author Response: Cited from http://journals.iucr.org/services/cif/checking/PLAT041.html
 "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."

 SHELXL97 really assigns 0.08 to the _atom_site_occupancy field for all of the
 methanol molecule atoms that results in an awful miscount for O, C, and H
 atoms in the checkCIF report. Manual correction of _atom_site_occupancy in the
 CIF (addition of trailing "3"-s to 0.08 for the methanol molecule atoms)
 cannot completely eliminate the problem. In the asymmetric unit of (II), there
 are four H-atoms with site occupancy factors 1/12 (0.083333...) each
 disordered between 12 positions. When the CheckCIF routine computes the
 formula, it uses the _atom_site_occupancy data taken from the provided CIF. It
 seems to us that the program truncates (rounds) the figures and considers only
 3 decimal digits. In case of compound (II), this gives a 1/3000 x 12 x 4 =
 0.016 underestimate of the H-atoms content. If rounded up to 2 decimal digits,
 it gives a 0.02 underestimate for the H-atom content and this is observed in
 the checkCIF report. As for C4 and O1, this error is only 0.004, and the
 checkCIF reports integer numbers of O and C atoms. We were also confused with
 this miscount, but this seems to be just an intrinsic "bug" of the checkCIF
 program.

PLAT906_ALERT_3_C Large K value in the Analysis of Variance ......      2.471      

Alert level G PLAT005_ALERT_5_G No _iucr_refine_instructions_details in the CIF ? Do ! PLAT007_ALERT_5_G Note: Number of Unrefined Donor-H Atoms ........ 1 PLAT042_ALERT_1_G Calc. and Reported MoietyFormula Strings Differ ? Check
Author Response: See above.
PLAT301_ALERT_3_G Note: Main Residue  Disorder ...................         30 %    
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          6      
PLAT779_ALERT_4_G Suspect or Irrelevant (Bond) Angle in CIF .... #        182      
              O1   -C4   -H4B     5.555   1.555   1.555              3.10 Deg. 
PLAT779_ALERT_4_G Suspect or Irrelevant (Bond) Angle in CIF .... #        204      
              O1   -C4   -H4C     3.555   1.555   1.555              3.40 Deg. 
PLAT961_ALERT_5_G Dataset Contains no Negative Intensities .......          ! Check

0 ALERT level A = Most likely a serious problem - resolve or explain 0 ALERT level B = A potentially serious problem, consider carefully 2 ALERT level C = Check. Ensure it is not caused by an omission or oversight 8 ALERT level G = General information/check it is not something unexpected 2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 2 ALERT type 3 Indicator that the structure quality may be low 3 ALERT type 4 Improvement, methodology, query or suggestion 3 ALERT type 5 Informative message, check

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