Structure of the basic uranyl salts and polyuranates

In the present investigation the structure of Li/sub 2/U/sub 3/O/sub 10/ was studied with the aid of single crystals and also the structure of the synthetic zippeite Zn(UO/sub 2/)SO/sub 4/-(OH)/sub 4/.1.5H/sub 2/0, which is interesting from the point of view of analyzing the role of bridging hydroxo groups. In the three-dimensional U/sub 3/O/sub 10/ framework two basic structural elements have been isolated: infinite chains of (UO/sub 2/)O/sub 4/ octahedra and infinite strips of (UO/sub 2/)O/sub 5/ pentagonal bipyramids. The similarity and difference between this structure and the structures of H/sub 2/U/sub 3/O/sub 10/ and D/sub 2/U/sub 3/O/sub 10/ are discussed. The crystal structure of Zn(UO/sub 2/)/sub 2/SO/sub 4/(OH)/sub 4/.1.5H/sub 2/O--the first representative of uranyl hydroxosulfates - has been determined. In this structure there are hydroxouranylsulfate layers linked by bivalent cations. The hydroxo groups coordinated by UO/sub 2//sup 2 +/ groups make the maximum use of their coordination possibilities, being tridentate-bridging ligands.