Synthesis of a new compound in the La-Cu-V-O system: La3Cu2VO9

A new quaternary compound, La3Cu2VO9, was synthesized and studied by XRD, TEM and EDS. The phase was found to be stoichiometric and stable in air up 1000 °C. From powder XRD data the crystalline phase could be described by a hexagonal unit cell, with the parameters ah= 14.4427(7) Å, ch= 10.685(1) Å and cell volume of 1930.15 Å3. Electron diffraction studies yielded a 4 times larger monoclinic supercell with the parameters am = 14.4427 Å, bm = 10.685 Å, cm= 52.07 Å, and β = 106.1 °. The valence states of Cu and V are discussed with respect to conducting and catalytic properties.