Bridgman crystal growth of Yb2Ru3Ge4 - A ternary germanide with a three-dimensional network of condensed distorted RuGe5 and RuGe6 units

摘要

The germanide Yb2Ru3Ge4 was synthesized from the elements using the Bridgman crystal growth technique. The monoclinic Hf2Ru3Si4 type structure was investigated by X-ray powder and single crystal diffraction: C2/c, Z = 8, a = 1993.0(3) pm, b = 550.69(8) pm, c = 1388.0(2) pm, beta = 128.383(9)degrees, wR(2) = 0.0569, 2047 F-2 values, and 84 variables. Yb2Ru3Ge4 contains two crystallographically independent ytterbium sites with coordination numbers of 18 and 17 for Yb1 and Yb2, respectively. Each ytterbium atom has three ytterbium neighbors at Yb-Yb distances ranging from 345 to 368 pm. The shortest interatomic distances occur for the Ru Ge contacts. The three crystallographically independent ruthenium sites have between five and six germanium neighbors in distorted trigonal bipyramidal (Ru1Ge(5)) or octahedral (Ru2Ge(6) and Ru3Ge(6)) coordination at Ru-Ge distances ranging from 245 to 279 pm. The Ru2 atoms form zig-zag chains running parallel to the b-axis at Ru2-Ru2 of 284 pm. The RuGe5 and RuGe6 units are condensed via common edges and faces leading to a complex three-dimensional [Ru3Ge4] network. (c) 2006 Elsevier Inc. All rights reserved.