Multiple Ion Substitution in the Perovskite Lattice

Abstract

An experimental study has been made of the possibilities and limitations of ionic substitution in the perovskite lattice. Especial attention has been paid to those cases in which more than one type of ion occupies any or all the cation and anion positions. A fairly large number of new oxide phases typified by such compositions as KLaTi 2 O 6 , Sr 2 CrTaO 6 , Ba 3 NiNb 2 O 9 , and BaK‐TiNbO 6 have been synthesized and shown to have the perovskite structure. Anion substitution successfully yields compounds with this structure only when it is complete; no mixed‐anion perovskites have been encountered. Few perovskites with anions other than O 2 ‐or F‐have been found. The importance of valence differences in limiting the extent of ionic replacement appears to have been clearly demonstrated.