Description of Ionic Crystals

Ionic crystals are described by contrasting the concepts of perfect versus real crystals. The notion of structure elements, such as normal elements and defects and their effective charges, are explained by using the Kroger–Vink notation. The main types of atomic disorder (Schottky, Frenkel) and electronic disorder are also discussed, along with the formation of solid solutions by doping, which includes a description of the predominant defects. Emphasis is placed on writing the chemical reactions that involve these structure elements and the corresponding equilibrium constants, which allows us to make Brouwer diagrams for solid solutions and to discuss the possible use of such solutions as electrolyte or electrode material. The topics treated in the exercises enrich the reader’s background in solid state chemistry and, in particular, with ionic defects.