Stability of AB 1 / 2 ′ B ″ 1 / 2 O 3 ‐ Type Mixed Perovskite Proton Conductors

Several mixed perovskites of the type , where A is and B ' and B '' are trivalent and pentavalent ions, respectively, were synthesized by calcining requisite mixtures of , , and in air. X‐ray diffraction confirmed the formation of the perovskite phase in each of the samples synthesized. The as‐calcined powders were boiled in water to examine their stabilities in water. All mixed perovskites were found to be stable. By contrast, and decomposed when boiled in water while was found to be stable. Madelung energies of simple and mixed perovskites were computed. The higher stability of mixed perovskites compared to simple perovskites of the type , such as and , where B is a tetravalent ion, was rationalized on the basis of lower Madelung energies of mixed perovskites. © 1999 The Electrochemical Society. All rights reserved.