Studies were made of the effect of point defects upon the electronic structure, chemical bonding and conduction of MF2 (M = Ca, Sr, Ba, Pb) by using the non-empirical LMTO method, in the tight-binding approximation, and Hückel's semi-empirical method. The energies of formation and interaction of anti-Frenkel defects were calculated, and the effect of defect clustering was detected. The latter effect was responsible for the emergence of the superionic state and the anomalous physico-chemical properties of these electrolytes. The nature of the instability of the fluorite structure was studied, and methods for its stabilization were proposed.

Defect Clusterization and Transport Properties of Oxide and Fluoride Ionic Conductors with Fluorite Structure - Quantum-Chemical Approach. V.M.Zaĭnullina, V.P.Zhukov: Physics of the Solid State, 2001, 43[9], 1686-99