Synthesis and structure determination of new layered perovskite compounds, ALaTa2O7 and ACa2Ta3O10(A = Rb, Li)

Abstract

New layered perovskite compounds of RbLaTa₂O₇ and RbCa₂Ta₃O₁₀, whose Rb⁺ ions can be ion-exchanged have been synthesized directly by a solid-state reaction. Lithium ion-exchanged compounds, LiLaTa₂O₇ and LiCa₂Ta₃O₁₀, have also been synthesized by ion-exchange reactions of the rubidium compounds with LiNO₃ molten salt. The crystal structures of these compounds have been determined by Rietveld analysis of their powder X-ray diffraction patterns. The crystal structures of these compounds are analogous to those of the corresponding niobate compounds. These compounds are new members of the Dion–Jacobson series with the general formula A[M_{n– 1}B_nO_{3n+ 1}](A = alkali metal), with n= 2 and 3.