Topochemical Strategies for the Formation of Alkali-metal Halide Arrays within Perovskite Hosts

Multistep topochemical reactions can be used to construct alkali-metal halide arrays within layered perovskite hosts. Combinations of ion exchange and reductive intercalation (A = Li) or reductive and oxidative intercalation (A = Rb) allow one to prepare the compounds such as (A 2 Cl)LaNb 2 O 7 . These products consist of perovskite blocks separated by double alkali-metal halide layers where the local layer structure is dependent on the size of the alkali cation. Details on the synthesis and structures of these materials are presented, and the general utility of the topochemical strategies used in their preparation is discussed.