checkCIF procedure

PLAT780

 Atoms given in a CIF should form a 'connected set', i.e. no symmetry   
 operations are needed to get atoms in a bonding position. A connected set of   
 atoms is not needed for the least squares refinement (unless hydrogen atoms
 are to be added at calculated positions). Geometry listings (bonds, angles,
 torsions & H-bonds) become unwieldy for non-connected atom sets.