The room temperature crystal structure (I4/mmm, a = 0.3929, c = 1.5476nm, Z = 1) of the fast O-ion conductor, Bi4(V0.85,Co0.15)2O11, was refined as an average tetragonal unit cell on the basis of single-crystal neutron diffraction data. The structure consisted of the intergrowth, along the c-axis, of alternating (Bi2O2)2+ sheets and O-deficient (VO3.52)2- perovskite-like layers. The material exhibited a high ionic conductivity at moderate temperatures, underwent a phase transition at about 780K. It was noted that O vacancies were localized in the perovskite-like layers.

Structural Studies of the Fast Oxygen Ion Conductor BICOVOX.15 by Single-Crystal Neutron Diffraction at Room Temperature. C.Muller, M.Anne, M.Bacmann, M.Bonnet: Journal of Solid State Chemistry, 1998, 141[1], 241-7