An average body-centered cubic structure (a = 0.43822nm) was determined by using powder neutron diffraction methods. Calculations which were based upon the space group, Im3m, showed that the Bi and Ba atoms were statistically distributed over the 2(a) sites, (0,0,0), whereas O and anionic vacancies were statistically distributed over the 6(b) sites, (½,0,0). The cationic positions and the large anisotropic thermal factors of the O atoms recalled the anti -AgI structure. However, the anionic positions corresponded to those observed in the perovskite. Unlike Cd0.79Cd0.21O1.39, this phase could not be considered to have an anti -AgI structure. It was better described as being made up of 2 coexisting configurations of the perovskite. Ionic conductivity measurements showed that this phase was an anionic conductor with an activation energy of 0.90eV and a conductivity at 673K of 0.001S/cm.

C.Michel, D.Pelloquin, M.Hervieu, B.Raveau, F.Abbattista, M.Vallino: Journal of Solid State Chemistry, 1994, 109, 122-6