Bridging the Ruddlesden-Popper and the Dion-Jacobson series of layered perovskites: synthesis of layered oxides, A_2-xLa₂Ti_3-xNb_xO₁₀(A=K, Rb), exhibiting ion exchange

Abstract

Solid solutions of the formula, A_2-xLa₂Ti_3-xNb_xO₁₀(A = K, Rb), exist for the range 0≤x≤1.0, bridging n = 3 members of the Ruddlesden-Popper series (A₂La₂Ti₃O₁₀) and the Dion-Jacobson series (ALa₂Ti₂NbO₁₀). For 0≤x≤0.75, the phases possess body-centred structures characteristic of the Ruddlesden-Popper phases, while the x = 1 members are isostructural with KCa₂Nb₃O₁₀(A = K) and CsCa₂Nb₃O₁₀(A = Rb). Protonated derivatives, H_2-xLa₂Ti_3-xNb_xO₁₀, which are prepared by ion exchange, retain the structural difference of the parent phases. A difference in the Bronsted acidity of the protonated derivatives revealed by intercalation experiments with organic bases seems to be related to this structural difference.