Uranyl perchlorate is a radioactive inorganic chemical compound or uranium with the formula UO2(ClO4)2·nH2O, where n equals 3, 5, and 7. They are all yellow-colored hygroscopic solids. The most common is the heptahydrate, UO2(ClO4)2·7H2O, which has historically been mischaracterized as a hexahydrate. It is used as a source of soluble uranyl ions.V. M. Vdovenko, L. G. Mashirov, V. K. Blokhina, I. G. Suglo-bova, D. N. Suglobov, Radiokhimiya, 1963, 5(1), 80.V. M. Vdovenko, L. G. Mashirov, D. N. Suglobov, Radiokhimiya, 1964, 6(3), 299.
Preparation and structure Solutions of uranyl perchlorate is produced by the dissolution of uranium(VI) oxide in 72% perchloric acid: UO3 + 2 HClO4 → UO2(ClO4)2 + H2O Evaporating the solution under vacuum gives the pentahydrate and subsequently the trihydrate, while the heptahydrate forms by the recrystallization of these lower hydrates. The monohydrate and anhydrous form have also been claimed to be formed when the trihydrate is heated in vacuum.
All hydrates of uranyl perchlorate contain 7-coordinate uranium centers. + Crystallographic data for the 3 hydrates of uranyl perchlorateHydrateTrihydratePentahydrateHeptahydrateStructural formulaUO2(ClO4)2(H2O)3[UO2(H2O)5](ClO4)2[UO2(H2O)5](ClO4)2·2H2OCrystal StructureMonoclinicMonoclinicOrthorhombicSpace groupP21/cP21/nPbcnLattice constant a (Å)5.455.299.21Lattice constant b (Å)18.1116.4510.68Lattice constant c (Å)10.3210.6814.46β90.02°99.85°Z444Calculated density (g/cm3)3.3672.8712.696
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