Molecular crystals with a sole bearing contact: structural classes and statistical data

Abstract

Abstract All the structural classes (SCs) of molecular crystals, which are possible to be formed by a sole intermolecular bearing contact, are derived from 1,1- and 2,1-transitive nets. There are 160 (167 including enantiomorphic pairs) monosystemic SCs (in which the molecules occupy one crystallographic orbit) and 244 (248) bisystemic SCs (in which the molecules occupy two crystallographic orbits), i.e. 404 (411) SCs in all. These are the only SCs which can correspond to a homodesmic crystal structure, either organic, or inorganic, in which the structural units are bonded in a single way. Statistical investigation of the Cambridge Structural Database (CSD) shows that ∼1% of monosystemic molecular crystals can be formed by a sole intermolecular bearing contact.