checkCIF procedure

PLAT307

 This test reports on metal atoms that are not bonded or at coordination
 distance of other atoms. Isolated ions are very unusual (or non-existent?)
 NOTE: Isolated metal atoms may be an artifact when their environment is part
 of the SQUEEZED density. Metal clusters may invoke this ALERT. It is not
 always clear, based on default geometrical radii, to properly distinguish
 bonds from contacts.