THE DEFECT CHEMISTRY OF LAMNO3+ -DELTA .5. THERMODYNAMICS/

The temperature dependence of the relationship between composition and oxygen partial pressure has been described for LaMnO3+delta and LaMnO 3-delta on the basis of an assessment of literature data obtained by T GA by several authors. The thermodynamics of defect formation is calcu lated on the basis of these results. For the formation of lanthanum an d manganese vacancies in LaMnO3+delta, it has been determined that DEL TAH(V)-degrees = (-380 +/- 6) kJ . mole-1, and DELTAS(V)-degrees = (-2 66 +/- 5) J . mole-1 . K-1. For the formation of oxygen vacancy cluste rs in LaMnO3-delta, DELTAH(V)-degrees = (349 +/- 6) kJ . mole-1, and D ELTAS(V)-degrees = (96.4 +/- 4.9) J . mole-1 . K-1. (C) 1994 Academic Press, Inc.