On CuDy{sub 2}[B{sub 8}O{sub 16}] and CuHo{sub 2}[B{sub 8}O{sub 16}]: two new ``metaborates`` with a {sub {proportional_to}}{sup 1}[B{sub 8}O{sub 16}]{sup 8-} anion; Ueber CuDy{sub 2}[B{sub 8}O{sub 16}] und CuHo{sub 2}[B{sub 8}O{sub 16}]: zwei neue ``Metaborate`` mit einem {sub {proportional_to}}{sup 1}[B{sub 8}O{sub 16}]{sup 8-}-Anion Wiesch, A; Bluhm, K [Kiel Univ. (Germany). Inst. fuer Anorganische Chemie]; Timm, H [Hannover Univ. (Germany). Inst. fuer Physikalische Chemie und Elektrochemie] 36 MATERIALS SCIENCE; COPPER COMPOUNDS; DYSPROSIUM COMPOUNDS; HOLMIUM COMPOUNDS; CRYSTAL GROWTH; SPACE GROUPS; BOND LENGTHS; X-RAY DIFFRACTION; CRYSTAL LATTICES; BINDING ENERGY; SYMMETRY Nearly colourless single crystals of the compounds CuDy{sub 2}[B{sub 8}O{sub 16}] (I) and CuHo{sub 2}[B{sub 8}O{sub 16}] (II) have been obtained by a B{sub 2}O{sub 3} flux technique. They crystallize in the structure of CuTb{sub 2}[B{sub 8}O{sub 16}] (I) or in an orthorhombic variant (II). X-ray investigations on single crystals led to the space group C{sup 5}{sub 2h} - P2{sub 1}/c (Nr. 14) with lattice parameters a = 1025.5(10); b = 836.99(10); c = 621.2(8) pm, {beta} = 90.47(10) ; Z = 2 (I) and D{sup 9}{sub 2h} - Pbam (Nr. 55) with a = 840.7(2), b = 616.6(2), c = 1022.0(2) pm, Z = 2 (II). The structures contain {sup 1}{sub {infinity}}[B{sub 8}O{sub 16}]{sup 8-} chains isolated from each other, which include tri- and tetracoordinated boron. The chains consist of alternating twelve and eight-membered rings of boron and oxygen atoms connected by BO{sub 4} units. Dy{sup 3+} and Ho{sup 3+} are octacoordinated and Cu{sup 2+} is hexacoordinated in elongated octahedra by oxygen. The relation between these two structures is discussed. (orig.) 16 refs. Germany 1998-01-01 German Journal Article Journal Name: Zeitschrift fuer Naturforschung, B: Chemical Sciences; Journal Volume: 53; Journal Issue: 1; Other Information: PBD: Jan 1998 Medium: X; Size: pp. 1-4 https://doi.org/ [] 1 53 Journal ID: ZNBSEN; ISSN 0932-0776; TRN: DE98F6176 DEN; SCA: 360202; PA: DEN-98:0F6176; EDB-98:039059; SN: 98001931487 2010-12-29 585848