Zur Kenntnis von RbTaO3 – ein neuer Typ einer Schichtstruktur

On the Knowledge of RbTaO₃ – a New Type of a Layer Structure RbTaO₃ crystallizes monoclinic with a = 9.58₉, b = 8.50₅, c = 8.13₅ Å, β = 94.8₇°, Z = 8, space group C2/m. The crystal structure (Fourcircle-diffractometer data, 4° ≤ Θ ≤ 33°, 1014 hkl, MoKα, R = 9,9%) shows sheets [TaO₃] connected by Rb; one half of Ta is surrounded by O octahedrally, the other part tetragonal-pyramidal. Effective Coordination Numbers, ECoN, and the Madelung Part of Lattice Energy, MAPLE, have been calculated and are discussed.