Ionic Radii in Mixed-Valence and Nonstoichiometric Metal Oxides and Their Polymorphic Forms

Abstract

A linear dependence of was found for ionic radii on the cube root of molecular volume standardised per oxygen atom (M a/b O) of MO oxides of alkali earth metals, M2O oxides of alkali metals and MO2 oxides of f-electron metals, and parameters of the linear equation were calculated. This equation makes it possible to predict mean ionic radii of metals in compact structures of polymorphic forms of oxides, mixed-valence oxides and oxides showing deviation from stoichiometry, otherwise not accessible. It is possible to predict mean ionic radii of metals in compact structures of polymorphic forms of oxides, mixed-valence oxides and oxides showing deviation from stoichiometry, otherwise not accessible, knowing the molecular volume standardised per oxygen atom of (M a/b O) of MO oxides of alkali earth metals, M2O oxides of alkali metals and MO2 oxides of f-electron metals. Fig. The relation between the cube root of the molecular volume of oxides $$ \left(\root{3}\of{{V_{{\text{eff}}}^{\text{m}} }}\right) $$ and the radii of the respective metal ions.