Transforming n = 1 members of the Ruddlesden-Popper phases to a n=3 member through metathesis: synthesis of a new layered perovskite, Ca2La2CuTi2O10

摘要

We report the formation of a new n = 3 Ruddlesden-Popper (R-P) layered perovskite oxide, Ca2La2CuTi2O10 (I), in the metathesis reaction between NaLaTiO4 and Ca2CuO2Cl2 (n = 1 R-P phases) at 700degreesC in air. Rietveld refinement of powder XRD data shows that I is isostructural with Sr4Ti3O10 (space group I4/mmm; a = 3.8837(5), c = 27.727(6) Angstrom), consisting of triple perovskite CuTi2O10 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 CuO2 sheets in the structure. I is metastable decomposing at higher temperatures (similar to950degreesC) to a mixture of perovskite-like CaLa2CuTi2O9 and CaO. Interestingly, the reaction between NaLaTiO4 and Sr2CuO2Cl2 follows a different metathesis route, 2NaLaTiO(4) + Sr2CuO2Cl2 --> La2CuO4 + 2SrTiO(3) + 2NaCl, revealing multiplicity of reaction pathways for solid-state metathesis reactions. (C) 2004 Elsevier Inc. All rights reserved.