The anhydrous and hydrated materials had tetragonal (a = 0.525, c = 0.818nm) and orthorhombic (a = 0.874, b = 1.395, c = 0.523nm) structures, respectively, at room temperature. The conduction was due mainly to anionic vacancy motion, with an activation energy of 0.36eV. The Schottky defect formation energy was deduced to be 2.8eV.

T.A.Kuku: Solid State Ionics, 1987, 25[2-3], 105-8