Coordination Numbers and Critical Topology of Centrosymmetric Hydrocarbons

Abstract

Various types of coordination numbers in molecular crystals are discussed. The relationship between parameter R of the Delone system, coordination number (CN), topological type, and the intermolecular interaction energy is studied on the example of crystal structures of centrosymmetric hydrocarbons. The first coordination sphere of a molecule takes 86.2±1.6% of the lattice energy; the interactions providing molecular arrangement take at least 50% of the lattice energy for CN ≥ 6. The nets characterizing the framework of intermolecular interactions in this series of structures tend to the lowest cyclomatic number of the quotient graph.