Transforming n=1 members of the Ruddlesden–Popper phases to a n=3 member through metathesis: synthesis of a new layered perovskite, Ca 2La 2CuTi 2O 10

Abstract

We report the formation of a new n=3 Ruddlesden–Popper (R–P) layered perovskite oxide, Ca 2La 2CuTi 2O 10 ( I), in the metathesis reaction between NaLaTiO 4 and Ca 2CuO 2Cl 2 ( n=1 R–P phases) at 700°C in air. Rietveld refinement of powder XRD data shows that I is isostructural with Sr 4Ti 3O 10 (space group I4/ mmm; a=3.8837(5), c=27.727(6) Å), consisting of triple perovskite CuTi 2O 10 sheets wherein Cu and Ti are ordered at the central and terminal octahedral sites, respectively. Magnetization data provide support for the presence of strong antiferromagnetically coupled CuO 2 sheets in the structure. I is metastable decomposing at higher temperatures (∼950°C) to a mixture of perovskite-like CaLa 2CuTi 2O 9 and CaO. Interestingly, the reaction between NaLaTiO 4 and Sr 2CuO 2Cl 2 follows a different metathesis route, 2NaLaTiO 4+Sr 2CuO 2Cl 2→La 2CuO 4+2SrTiO 3+2NaCl, revealing multiplicity of reaction pathways for solid-state metathesis reactions.