Calculation of the structural and thermodynamic constants of normal chromium spinels

Abstract

The interstructural distances and crystal lattice parameters of complex chromium spinels of variable composition having five different cations are determined according to the earlier developed procedure taking into account their crystal lattices and calculated effective ionic radii. Using these structural characteristics, the enthalpy of the crystal lattice and the enthalpy of spinel formation are calculated. The composition-lattice parameter and composition-enthalpy of the formation diagrams are constructed for (Mg i 2+ Fe j 2+ )O • (Fe x 3+ Al y 3+ Cr z 3+ )2O3 spinels. They make it possible to determine the lattice parameter and the enthalpy of oxide formation for any spinel composition. © 2008 Pleiades Publishing, Ltd.