The Crystal Structures of Some Ternary Oxides and Fluorides

Abstract

<p> The crystal structures of five ternary oxides and fluorides have been determined. It is shown that the gross features of these structures and the coordination of the atoms can be described in terms of the theory of close-packing of spheres. However, in each of the structures there appear cations whose coordination cannot be uniquely predicted, as the cation-anion radius ratios are close to the critical value for transition from one coordination to another.</p>