Mn, Co oxides prepared by the thermal decomposition of carbonates

Abstract

Mixed Mn, Co carbonates of general formula Co 1−x Mn xCO 3 (x = 0.33, 0.5, 0.66) are used as precursors in the preparation of mixed oxides with rock-salt and spinel structures. The thermal decomposition of the precursors in air leads to cation-deficient spinels with O/M ratios close to 1.5 that are progressively reduced to M 3O 4 with increasing temperature. The decomposition in inert atmosphere leads to mixed monoxides, which are partially oxidized, especially those which are Mn containing. The values of a of the rock-salt phases increase with Mn content. The solid is composed of small domains of anisotropic sizes.