LA2CUSNO6 - A NEW PEROVSKITE-RELATED COMPOUND WITH AN UNUSUAL ARRANGEMENT OF B-CATIONS

The structure of La2CuSnO6 was determined by Rietveld refinement of time-of-flight powder neutron diffraction data. The structure was solved in space group P2(1)/m with unit-cell parameters a = 8.510(1), b = 7.815 (1), c = 7.817 (1) angstrom, and beta = 91.15 (1)-degrees. The structure is best described as a 2a(p) x 2a(p) x 2a(p) distorted perovskite with an unusual arrangement of B cations that produces distinct copper-oxygen and tin-oxygen layers. The structural aspects are similar to the high-temperature cuprate superconductors. The magnetic susceptibility versus temperature profile indicates the compound is not a superconductor above 5 K. The phase diagram of the LaO1.5-CuO-SnO2 system was determined at 980-degrees-C in air. La2CuSnO6 is the only ternary compound in the system.