Crystal chemistry of MSeO3 and MTeO3 (M = Mg, Mn, Co, Ni, Cu, and Zn)

New selenites and tellurites MgSeO3, MnSeO3, CoSeO3, NiSeO3, CuSeO3, MnTeO3, CoTeO3, and NiTeO3 were synthesized under high pressures and temperatures. All the compounds are isomorphous and their crystal system is orthorhombic. Structure analyses were carried out for all the selenites and CoTeO3. The structure is described as a salt of M2+ and SeO32− or TeO32− ions or as a distorted perovskite. In these compounds an Se or Te atom is closely linked to three oxygen atoms to form a flattened trigonal pyramid. The features of this coordination are discussed. At low temperature, magnetic order appears in all the compounds containing iron group ions, among which CuSeO3 is a ferromagnet with the Curie temperature of 26°K.