Synthesis and structure of Cs[UO2(SeO4)(OH)] · nH2O (n = 1.5 or 1)

Abstract

The synthesis and single-crystal X-ray diffraction study of Cs[UO2(SeO4)(OH)] · 1.5H2O (I) and Cs[UO2(SeO4)(OH)] · H2O (II) are performed. Compound I crystallizes in the monoclinic crystal system, a = 7.2142(2) A, b = 14.4942(4) A, c = 8.9270(3) A, β = 112.706(1)°, space group P21/m, Z = 4, and R = 0.0222. Compound II is monoclinic, a = 8.4549(2) A, b = 11.5358(3) A, c = 9.5565(2) A, β = 113.273(1)°, space group P21/c, Z = 4, and R = 0.0219. The main structural units of crystals I and II are [UO2(SeO4)(OH)]− layers which belong to the AT3M2 crystal chemical group of uranyl complexes (A = UO22+, T3 = SeO42−, and M2 = OH−). In structure I, johannite-like layers are found. Structure II is a topological isomer of I. The two structures differ in the number of U(VI) atoms bound to the central atom by all bridging ligands.