STRUCTURE OF LACUO3 BY POWDER NEUTRON-DIFFRACTION

Lanthanum copper oxide, LaCuO3, M(r) = 250.46, hexagonal, P6(3), a = 5.50195 (1), c = 13.2124 (4) angstrom, V = 346.4 angstrom-3, Z = 6, D(x) = 7.20 g cm-3 at room temperature; a = 5.49219 (1), c = 13.1545 (2) angstrom, V = 346 angstrom-3 at 5 K, R(p) = 6.2%. The structure of the title compound, synthesized at 5 x 10(9) Pa, was refined using time-of-flight powder neutron diffraction methods. The structure is perovskite based with octahedral copper(III), Cu-O 1.9511 (3) angstrom, and a strongly distorted 12-coordinated lanthanum, La-O 2.483 (2)-3.019 (2) angstrom.