Thermal Decomposition Behavior of Heteronuclear Complexes, Ln[Co(CN)₆]⋅nH₂O (Ln=La-Yb)

Abstract

The thermal decomposition behavior of Ln-Co (1:1) cyano complexes and the composition of decomposition products have been examined. Decomposition of their CN-bridged structures proceeded on heating at about 300°C in air, generating amorphous phases containing carbonate complexes. For the complexes comprising La-Nd, submicron sized particles of perovskite-type oxide were formed (without single phase oxides Co₃O₄ and Ln₂O₃) from an amorphous phase by heating at about 620°C. For the complexes comprising Eu, Gd and Dy, a mixture of single oxides (Co₃O₄ and Ln₂O₃) and perovskite-type oxide was formed. The content of the perovskite-type oxide increased with the increase in decomposition temperature. For the complexes containing Ho and Yb the corresponding perovskite-type oxide could not be obtained even when the complex was decomposed at 1100°C.