checkCIF procedure

PLAT905

 Scale Factors (i.e. K = Mean[F(obs)**2] / Mean [F(calc)**2]) for selected
 groups of reflections, as listed in the Analysis of Variance Section #7 of
 the FCF validation report, are expected to have a value of about 1.000.
 Strong deviations should be investigated, acted upon or explained. (see also
 SHELXL manual). A reason can be meaningless (weak) high order data where a
 cut-back of the resolution might be indicated. Incorrect background treatment
 can lead to numerous negative observed intensities for weak reflections (i.e.
 F(calc) close to zero. For details see the Analysis-of-Variance Section 7 in
 the validation '.ckf' file.