(IUCr) Crystallography Journals Online checkcif report

[Contents scheme]

Acta Cryst. (2005). E61, o851-o853 [ doi:10.1107/S1600536805006264 ]

3-Cyano-N-methylpyridinium bromide

J. T. Mague, R. M. Ivie, R. W. Hartsock, L. V. Koplitz and M. Spulak

Online 4 March 2005

Key indicators

Single-crystal X-ray study
T = 100 K
Mean (C-C) = 0.002 Å
R factor = 0.029
wR factor = 0.063
Data-to-parameter ratio = 101.2

checkCIF/PLATON results

No syntax errors found



Alert level A
REFLT03_ALERT_3_A  Reflection count > 15% excess reflns - sys abs data present?
           From the CIF: _diffrn_reflns_theta_max           27.74
           From the CIF: _diffrn_reflns_theta_full           0.00
           From the CIF: _reflns_number_total               6277
           TEST2: Reflns within _diffrn_reflns_theta_max
           Count of symmetry unique reflns         1054
           Completeness (_total/calc)            595.54%

Author Response: ...Crystal was twinned so final refinement was performed with a SHELX HKLF5-type multicomponent file. Such a refinement with SHELXL requires that no merging of equivalent reflections be performed. This is to avoid averaging symmetry equivalent reflections with differing contributions from the two twin components. This is the reason for the "excess reflections". This is addressed in the _publ_section_exptl_refinement section.

PLAT021_ALERT_1_A Ratio Unique / Expected Reflections too High ...       5.95

Author Response: ...Same as previous response.


Alert level B
PLAT230_ALERT_2_B Hirshfeld Test Diff for    C3     -   C7      ..       8.09 su    

Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.96       
PLAT371_ALERT_2_C Long   C(sp2)-C(sp1) Bond  C3     -   C7     ...       1.44 Ang.  

   2 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   2 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
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion