Preparation of perovskite-type oxides by the thermal decomposition of heteronuclear complexes, Ln[FexCo1-x(CN)(6)]center dot 4H(2)O(Ln=Pr-Yb)

Heteronuclear complexes of Ln[FexCo1-x(CN)(6)].4H(2)O(Ln=PT-Yb) were synthesized and their thermal decomposition products were investigated. Thermal decomposition of the complexes results in the formation of perovskite-type oxides for Ln=Pr-Gd even at 800 degrees C. The lattice parameters, a-, b-and c-lattice constants (crystal system: orthorhombic) increase linearly with the ratio of Fe/Co for the perovskite-type oxide. For Ln=Dy through Yb, the Ln(2)O(3) phase is observed as the major product for x=0, but its content decreased with an increase in the Fe content; however, a single phase of the perovskite-type oxide was not formed for x=1. The perovskite-type structure for the Fe systems is easier to form compared with the Co systems. We clarified that the formation of the perovskite-type oxide is mainly affected by the ionic radius of the Ln(3+) ion and the T3+ ion (T=Fe or Co).