checkCIF procedure

PLAT702

 Bond Angles given in the CIF are cross-checked with corresponding values   
 calculated from the coordinates.  Alerts are set at 1,2 and 3 Sigma
 deviation levels.  
 In general, all differences should be within the associated s.u. Small
 differences may arise from rounding. Very large deviations normally indicate
 incorrectly specified symmetry operations on the associated atoms, or
 'cut-and-pasting' of incompatible CIF's.