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

The synthesis and single-crystal X-ray diffraction study of Cs[UO2(SeO4)(OH)] center dot 1.5H(2)O (I) and Cs[UO2(SeO4)(OH)] center dot H2O (II) are performed. Compound I crystallizes in the monoclinic crystal system, a = 7.2142(2) , b = 14.4942(4) , c = 8.9270(3) , beta = 112.706(1)A degrees, space group P2(1)/m, Z = 4, and R = 0.0222. Compound II is monoclinic, a = 8.4549(2) , b = 11.5358(3) , c = 9.5565(2) , beta = 113.273(1)A degrees, space group P2(1)/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 AT (3) M (2) crystal chemical group of uranyl complexes (A = UO (2) (2+) , T (3) = SeO4 (2-), and M (2) = 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.