Röntgenstrukturanalyse von zwei Verbindungen des Kupfertyps BaMLn2O5 (M = Zn, Ln = Sm, Tm) und von BaSmAIZn3O7 / X-Ray Analysis of Two Compounds of the Copper Type BaMLn2O5 (M=Zn, Ln=Sm, Tm) and of BaSmAlZn3O7
Abstract Kupfertyps BaMLn2O5 (M=Zn, Ln=Sm, Tm) und von BaSmAIZn3O7 X-Ray Analysis of Two Compounds of the Copper Type BaMLn2O5 (M=Zn, Ln=Sm, Tm) and of BaSmAlZn3O7 The barium zinc lanthanoide oxides BaZnSm2O5 (I) and BaZnTm2O5 (II) crystallize in the BaCuLn2O3 copper type with orthorhombic symmetry, space group D162h,Pnma, (I)a = 12.575(2), b = 5.804(1), c = 7.198(1) Å and (II): a = 12.258(2), b = 5.684(1), c = 7.010(2) Å, Z = 4. Zinc shows square pyramidal oxygen coordina tion, but the strong elongation of the CuO5 pyramid in the copper type is missing. BaSmAlZn3O7 crystallizes in the space group C46V-P63mc, a = 6.346(1), c = 10.237(3) Å, Z = 2. The metal coordination of oxygen and the shifts of the ratio Al : Zn at the sites (6c) and (2a) depending on the size of the lanthanoid ions are discussed.