The La2O3-CuO-TiO2 system in air at 960°C contains two perovskite-related ternary compounds, La2CuTiO6 and [La2/3□2/3Cu3](Ti4)O12. The former is orthorhombic, has cell parameters a = 5.587(6), b = 5.616(5), c = 7.842(7) Å, is isostructural with GdFeO3, and exhibits Curie-Weiss magnetic behavior. The copper and titanium are statistically distributed over one crystallographic site. The La2O3-CuO-TiO2 and La2O3-CuO-SnO2 systems differ in their phase relationships, number of ternary phases, and crystal chemistry of their La2CuMO6 (M = Ti, Sn) compounds. Single crystals of [La0.86□0.14Cu3](Ti3.42Al0.58)O12 were grown in an Al2O3 crucible from a CuO-TiO2 flux and crystallize in the cubic space group /m3̄ with a = 7.421(1) Å and Z = 2. The compound is isostructural with [CaMn3](Mn4)O12. The excess lanthanum in the crystal compensates the charge deficiency brought about by the aluminum incorporation, and the electrostatic stabilization it affords is the principal driving force for the observed structure.
ASJC Scopus subject areas
- Materials Chemistry
- Physical and Theoretical Chemistry
- Inorganic Chemistry