SYNTHESIS AND CHARACTERIZATION OF SERIES OF ISOTYPE PEROVSKITE TITANATES OF (CACU3) (MN4)O12

A series of titanates which have perovskite-like arrangements and are isostructural with [CaCu3](Mn4)O12 have been synthesized. The total charge of the A sites can be modified (1) by substituting the Ca2+ cations with monovalent ones and the tetravalent manganese cations of the B sites by a mixture of (Ti4+ + M5+) in which M = Ta, Nb, Sb, or (2) by substituting the Ca2+ cations by a combination of cations plus vacancies. In this case, if the total charge of the A sites is 2, one obtains compounds such as [Th4+ 1 2□ 1 2Cu3](Ti4)O12 and [T3+ 2 3□ 1 3Cu3](Ti4O12 (T = rare earth); on the contrary, if the charge is less than 2, then one has to compensate it by changing that of the B sites. This leads to compounds such as [□Cu3](Ti2M2)O12 (M = Ta, Nb, Sb). © 1979.