Structure Determination and Infrared Spectroscopy of K(UO2)(SO4)(OH)(H2O) and K(UO2)(SO4)(OH)

Abstract

Two potassium uranyl sulfate compounds were synthesized, and their crystal structures were determined by single-crystal X-ray diffraction. K(UO2)(SO4)(OH)(H2O) (KUS1) crystallizes in space group P21/c, a = 8.0521(4) A, b = 7.9354(4) A, c = 11.3177(6) A, beta = 107.6780(10) degrees , V = 689.01(6) A3, and Z = 4. K(UO2)(SO4)(OH) (KUS2) is orthorhombic Pbca, a = 8.4451(2) A, b = 10.8058(4) A, c = 13.5406(5)A, V = 1235.66(7)A3, and Z = 8. Both structures were refined on the basis of F2 for all unique data collected with Mo Kalpha radiation and a CCD-based detector to agreement indices R1 = 0.0251 and 0.0206 calculated for 2856 and 2616 reflections for KUS1 and KUS2, respectively. The structures contain vertex-sharing uranyl pentagonal bipyramids and sulfate tetrahedra linked into new chains and sheet topologies. Infrared spectroscopy provides additional information about the linkages between the sulfate and uranyl polyhedra, as well as the hydrogen bonding present in the structures. The U-O-S connectivity is examined in detail, and the local bond angle is impacted by the steric constraints of the crystal structure.