checkCIF procedure

PLAT992

 The '_reflns_number_gt' values as reported in the CIF and the actual one as
 calculated with the data in the FCF are found to differ. The FCF based R1
 value is calculated by checkCIF to cross-check with the R1 value as
 reported in the CIF. The number of 'observed' reflections that goes into that
 calculation is based on the criterium I > 2.0 * Sigma(I). A refinement
 program like SHELXL uses F(obs) > 4.0 * Sigma(F(obs)) as 'observed' criterium
 in its calculation of R1. Both numbers may differ slightly for numerical
 reasons. Large differences may point to inconsistencies between the CIF and
 FCF that need to be investigated.