CUYB2GE4O12, A NEW BIDIMENSIONALLY TUNNELED STRUCTURE

摘要

Employing CuO as self flux crystals of CuYb2Ge4O12 have been grown for the first time, The crystal structure of CuYb2 Ge4O12 has been determined by single-crystal X-ray diffraction in the triclinic P (1) over bar (No. 2) space group to an R value of 6.1%, with a = 7.156(2) Angstrom, b = 7.937(3) Angstrom, c = 4.905(3) Angstrom, alpha = 86.63(3)degrees, beta = 102.41(4)degrees, gamma = 114.12(3)degrees, V = 248.2(2) Angstrom(3), Z = 1, and D-c = 5.97 gcm(-3). The novel tridimensional CuYb2Ge4O12 structure type can be conceived as formed by layers of (GeO4)(4) units of vertex-sharing GeO4 tetrahedra, chains of YbO7 polyhedra, and isolated CuO4 squares connecting (GeO4)(4) units, with channels or tunnels of size up to 4.08 Angstrom in the a and c directions. A comparison is made between the structure types of the title germanate and recently reported CuNd2Ge2O8. The temperature dependence from 350 to 1.8 K of the reciprocal de magnetic susceptibility for CuYb2Ge4O12 is shown and presents a deviation from linearity over the whole temperature range. The infrared spectrum between 1000 and 100 cm(-1) is given and related with those of comparable species. (C) 1996 academic Press, Inc. [References: 20]