Ein beitrag zur synthese und kristallstruktur eines gemischtvalenten bariumoxotitanats: Ba2Ti123+Ti4+O22

Abstract Single crystals of Ba 2 Ti 13 O 22 were prepared by a high energy CO 2 laser. The crystal structure was determined by X-ray techniques. It crystallizes with orthorhombic symmetry, space group D 2h 18 (Cmca), a = 10.0183 A , b = 11.5747 A , c = 14.0940 A , Z = 4 . The crystal chemistry is partly related to the cubic perovskites, but it exhibits individual modifications of the TiO network and so-far unknown face-shared Ti 2 3+ O 9 double octahedra for example. The Ti 4+ ions occupy only one point position as can be shown by calculations of the partial Coulomb terms ( maple ) of lattice energy.