PLAT020

 The value of Rint (i.e. _diffrn_reflns_av_R_equivalents) should normally be
 considerably less than 0.12 and in the order of magnitude of the reported
 R-values. Rint may be relatively meaningless when based on a very limited
 number of averaged data. Higher values should be accompanied by a suitable
 explanation in the _publ_section_exptl_refinement section. However,
 authors should first ensure that there are not overlooked problems
 associated with the data or the space-group. Elevated values for 
 _diffrn_reflns_av_R_equivalents may be indicative of a need to recollect 
 the data from a crystal of higher quality or that there is a problem with
 the data treatment. Consider the following:
 (a) The absorption corrections are inadequate or inappropriate.
 (b) The overall quality of the data may be poor due to the crystal quality.
 (c) The crystal is very weakly diffracting, so that a large proportion of
     essentially "unobserved" reflections are being used in the refinement.
     You should consider using a better crystal or a data collection at
     low temperature and/or, if the compound is organic, using Cu radiation.
 (d) You are working in the wrong crystal system or Laue group.
 (e) You have only a very small number of equivalent reflections, which
     may lead to artificially high values of _diffrn_reflns_av_R_equivalents 
 Note that if _diffrn_reflns_av_sigmaI/netI is also large, the quality
 of the data should be considered to be suspect.