(IUCr) Crystallography Journals Online checkcif report

[Contents scheme]

Acta Cryst. (2008). E64, o1040-o1041 [ doi:10.1107/S1600536808013056 ]

(4R,5S)-5-Benzyl-4-isopropyl-1,3,4-oxadiazinan-2-one

L. D. Addison, D. D. Dore, S. R. Hitchcock and G. M. Ferrence

Online 10 May 2008

Key indicators

Single-crystal X-ray study
T = 100 K
Mean (C-C) = 0.005 Å
R factor = 0.060
wR factor = 0.134
Data-to-parameter ratio = 11.4

checkCIF/PLATON results

No syntax errors found




Alert level C
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

Author Response: The few low precision bonds above the test threshold are only barely so. The refinement seems to be the best possible for the dataset. Having two independent molecules in the unit cell provides access to better average bond precision for those in question.

PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?

Author Response: SADABS calculated a "Ratio of minimum to maximum apparent transmission: 0.859376". This seems anomalously low for a C,H,N,O structure, but commonly occurs when using SADABS. The values calculated by SHELXL seem to be equally meaningful, so they were reported unchanged.


PLAT720_ALERT_4_C Number of Unusual/Non-Standard Labels ..........          8

Author Response: Our labeling scheme was analogous to past related structures.

PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2      
              C13 H18 N2 O2

Author Response: Choice of residue location is better for H-bond viewing when looking at asymmetric unit alone.


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           28.28
           From the CIF: _reflns_number_total               3499
           Count of symmetry unique reflns         3498
           Completeness (_total/calc)            100.03%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         1
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no

Author Response: MERG 4 gives 3499 unique reflections; MERG 2 gives 6209 unique reflections, so there are 2710 Friedel pairs that were measured; however, final refinement was carried out using MERG 4.


PLAT791_ALERT_4_G Confirm the Absolute Configuration of C5A    ...          S

Author Response: We have checked them carefully and they are correctly assigned.


PLAT791_ALERT_4_G Confirm the Absolute Configuration of C5B    ...          S

Author Response: We have checked them carefully and they are correctly assigned.



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

   1 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
   1 ALERT type 3 Indicator that the structure quality may be low
   5 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check