Understanding the Topology of Simple Coordination Structures in Nonmolecular Solids – A Course on Symmetry and Catenation of Polyhedra

Abstract

Abstract We present a course explaining structural features found in inorganic ion crystals aiming to give an outline to lecturers for a stepwise introduction to specific structural phenomena. It deals with the symmetry of polyhedra and its modification starting from isolated ones to their catenation toward the three-dimensional entity. We furthermore treat the sometimes-puzzling interaction of the coordination number, polyhedral catenation, and stoichiometric ratio of the compounds and present working sheets to help with “reading” structures by an analysis of their pictorial presentations. We discuss a variety of effects leading to distortions of polyhedral symmetry induced by typical bonding effects. We also present rules to help understand polymorphic transitions induced by changes in temperature or pressure, and we discuss structural features which are indictive for high temperature or high-pressure regimes.