SYNTHESIS, THERMAL-BEHAVIOR, INFRARED-SPECTRA, AND CRYSTAL-STRUCTURE OF YB2(OH)2(CRO4)2 AND [YB2(OH)2(CRO4)2(H2O)2.5]BULLET-0.5H2O

The crystal structures of Yb2(OH)2(CrO4)2 and Yb2(OH)2(CrO4)2 · 3H2O were determined by conventional single-crystal X-ray diffraction technique. Crystals of Yb2(OH)2(CrO4)2 are monoclinic, space group P21c (No. 14) with a = 8.057(2)Å, b = 11.297(1)Å, c = 11.915(1)Å and β = 136.67(3), Z = 4, Dx = 5.46Mg m-3. Crystals of Yb2(OH)2(CrO4)2 · 3H2O are orthorhombic, space group Pccn (No. 56) with a = 10.884(2)Å, b = 12.023(1)Å, c = 16.033(8)Å, Z = 8, Dx = 4.22Mg m-3. In both compounds the coordination polyhedron of the eight oxygen atoms around ytterbium atoms is square antiprism. Structures form a three-dimensional network. Thermal behavior was investigated and IR spectra were recorded for both compounds. The thermal decomposition of Yb2(OH)2(CrO4)2 proceeds by a different mechanism than that of Yb2(OH)2(CrO4)2 · 3H2O. © 1992 Academic Press, Inc.