Acta Cryst. (2005). E61, o1196-o1197  [ doi:10.1107/S1600536805009669 ]

6,6'-Dioxo-2,2-bi(7-oxatricyclo[3.2.1.1^3,8]nonane)-4,4'-dicarboxylic acid

M.-L. Hu, Y.-Q. Cheng, S. Wang, J.-X. Yuan and X.-Q. Cai

Online 31 March 2005

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean (C-C) = 0.005 Å
• R factor = 0.040
• wR factor = 0.089
• Data-to-parameter ratio = 6.3

checkCIF/PLATON results

No syntax errors found




Alert level C
STRVA01_ALERT_4_C           Flack parameter is too small
           From the CIF: _refine_ls_abs_structure_Flack  -10.000
           From the CIF: _refine_ls_abs_structure_Flack_su   10.000
PLAT032_ALERT_4_C Std. Uncertainty in Flack Parameter too High ...      10.00       
PLAT033_ALERT_2_C Flack Parameter Value Deviates from Zero .......     -10.00       
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT089_ALERT_3_C Poor Data / Parameter Ratio (Zmax .LT. 18) .....       6.30       
PLAT230_ALERT_2_C Hirshfeld Test Diff for    O3     -   C6      ..       5.37 su    
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          5       

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           25.24
           From the CIF: _reflns_number_total                750
           Count of symmetry unique reflns          750
           Completeness (_total/calc)            100.00%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present           no

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 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

Copyright © International Union of Crystallography
IUCr Webmaster