SYNTHESIS AND CRYSTAL-STRUCTURE OF NIHO2( B2O5)2, THE FIRST NICKEL LANTHANOID BORATES WITH A(INFINITY)(2)(B2O5)(4-) ANION

Single crystals of NiHo2(B2O5)(2) were prepared by a B2O3 Aux-techniqu e in high temperature reactions at 1450 degrees C and investigated by X-ray diffraction. They crystallize in the space group C-2h(5)-P2(1)/c (Nr. 14) with a = 451.0(4); b = 724.8(3); c = 938.8(6) pm; beta = 91. 39(1)degrees; Z = 2. The compound is isotypic to CuTb2(B2O5)(2) as wel l as to the gadolinite structure (FeY2(BeSiO5)(2)) and contains a two dimensional infinite anion with the formula (2)(infinity)(B2O5)(4-). T he berate layers consist of four- and eight-membered rings of edge-sha ring BO4 tetrahedra. The layers are connected via copper-centered elon gated oxygen-octahedra and slightly distorted tetragonal HoO8 antipris ms.