Synthesis and Crystal Structure of Bi6 (Bi0.5Cu0.5)V2O15+y.

Abstract The structure of the oxide with composition Bi6(Bi0.5Cu0.5)V2O15+y has been solved based on single crystal X-ray diffraction and is found to be monoclinic (S. G. I2), a=11.276(1) A, b=5.4513(2) A, c=11.055(3) A, β=96.70°(1). The crystal was twinned by 180° rotoinversion about [ 1 ¯ 0 1] in the direct lattice as found in the the phosphates, Bi6TiP2O16 and Bi6+xM1−xP2O15+y (M=Mn, Fe and Ni), wherein chains of edge sharing (OBi4) tetrahedral units are connected by layers of VO4 tetrahedra and (Bi/Cu)O6−x (x=oxygen vacancies) octahedra.