checkCIF procedure

PLAT735

 A large ratio of the reported and calculated H-bond D-H distance s.u.'s is 
 found. The use of a DFIX instruction might cause such a warning since  
 calculated s.u.'s are based on reported variances only.
 NOTE: s.u.'s on the unit-cell dimensions are taken into account in the 
 calculation of expected s.u.'s. This may result in large differences   
 between expected and reported s.u.'s when this contribution is not included
 in the reported s.u.'s, in particular for inaccurate unit-cells.