PREPARATION OF PEROVSKITE-TYPE OXIDES BY THERMAL-DECOMPOSITION OF HETERONUCLEAR COMPLEXES, (LN[FE(CN)(6)]CENTER-DOT-NH(2)O)(X), (LN=LA-APPROXIMATE-TO-HO)

Perovskite-type oxides with submicron particle size were prepared by thermal decomposition of heteronuclear cyano complexes. Dehydration and decomposition of CN-bridged structure were performed by heating at similar to 300 degrees C in air, generating vitreous phases containing carbonates. For the complexes comprising La, Pr, Nd and Sm, submicron-sized particles of perovskite-type oxide directly formed from a vitreous phase. Single phase of perovskite-type oxide was formed by heating at similar to 600 degrees C of the complex with La. For the complexes comprising Gd, Dy and Ho, heat-treatment at similar to 300 degrees C led to formation of a vitreous phase containing carbonate and no perovskite-type oxide. By increasing the calcining temperature, a mixture of single oxides (Fe2O3 and Ln(2)O(3)) and perovskite-type oxides was formed at lower temperatures and single-phase perovskite-type oxide at higher temperatures. The formation temperature of the perovskite-type oxide increased with decreasing lanthanoid ion radius.