The crystal structure of Yb2(SO4)3•3H2O and its decomposition product, β-Yb2(SO4)3

Yb-2(SO4)(3)center dot 3H(2)O, synthesised by hydrothermal methods at 220(2) degrees C, has been investigated by single crystal X-ray diffraction. Yb-2(SO4)(3)center dot 3H(2)O crystallises in space group Cmc2(1) and is isostructural with Lu-2(SO4)(3)center dot 3H(2)O. The crystal structure has been refined to R-1=0.0145 for 3412 reflections [F-o > 3 sigma(F)]. and 0.0150 for all 3472 reflections. The structure of Yb-2(SO4)(3)center dot 3H(2)O is a complex framework of YbO6 octahedra, YbO8 and YbO5(H2O)(3) polyhedra and SO4 tetrahedra. Thermal data shows that Yb-2(SO4)(3)center dot 3H(2)O decomposes between 120 and 190 degrees C to form beta-Yb-2(SO4)(3). The structure of a twinned crystal of beta-Yb-2(SO4)(3) was solved and refined using an amplimode refinement in R3c with an R-1=0.0755 for 8944 reflections [F-o > 3 sigma(F)], and 0.1483 for all 16,361 reflections. beta-Yb-2(SO4)(3) has a unique structural topology based on a 3D network of pinwheels. (C) 2011 Elsevier Inc. All rights reserved.