Synthese und Kristallstruktur von NiHo2(B2O5)2, das erste Nickellanthanoidborat mit einem 2 ∞(B2O5)4- -Anion / Synthesis and Crystal Structure of NiHo2(B2O5)2, the First Nickel Lanthanoid Borates with a (B2O5)4- Anion

Abstract

Single crystals of NiHo2(B2O5)2 were prepared by a B2O3 flux-technique in high temperature reactions at 1450 °C and investigated by X-ray diffraction. They crystallize in the space group C2h 5-P21/c (Nr. 14) with a = 451.0(4); b = 724.8(3); c = 938.8(6) pm; β = 91,39( 1)°; Z = 2. The compound is isotypic to CuTb2 (B2O5)2 as well as to the gadolinite structure (FeY2(BeSiO5)2) and contains a two dimensional infinite anion with the formula 2 ∞ (B2O5)4-. The borate layers consist of four- and eight-membered rings of edge-sharing BO4 tetrahedra. The layers are connected via copper-centered elongated oxygen-octahedra and slightly distorted tetragonal HoO8 antiprisms.