Oxygen non-stoichiometry and redox thermodynamics of LaMn1 − xCoxO3 − δ

Abstract An experimental study of the oxygen non-stoichiometry and redox thermodynamics of LaMn 1 − x Co x O 3 ± δ (x = 0.25 and 0.75) is presented. The system shows partial solid solubility of LaCoO 3 in LaMnO 3 and vice versa. While both samples consist of two phases at room temperature, quenching experiments show that the x = 0.25 sample is single phase at high temperatures for the whole range of study, 0.6  2 /atm)  − 522 ± 40 kJ mol O 2 − 1 for x = 0.25 and 0.75, respectively. These data and analyses of literature data for LaMnO 3 and LaCoO 3 show that the enthalpy of oxidation varies nearly linearly with x. Solid solution thermodynamic models are used to analyze the redox mechanism.