Cation−Cation Interactions in Sr5(UO2)20(UO6)2O16(OH)6(H2O)6 and Cs(UO2)9U3O16(OH)5
journal contributionposted on 11.12.2006, 00:00 authored by Karrie-Ann Kubatko, Peter C. Burns
Two novel U6+ compounds, Sr5(UO2)20(UO6)2O16(OH)6(H2O)6 (SrFm) and Cs(UO2)9U3O16(OH)5 (CsFm), have been synthesized by mild hydrothermal reactions. The structures of SrFm (orthorhombic, C2221, a = 11.668(1), b = 21.065 (3), c = 13.273 Å, V = 3532.5(1) Å3, Z = 2) and CsFm (trigonal, R3̄c, a = 11.395(2), c = 43.722(7) Å, V = 4916.7(1) Å3, Z = 6) are rare examples of uranyl compounds that contain cation−cation interactions where an O atom of one uranyl ion is directly linked to another uranyl ion. Both structures are complex frameworks. SrFm contains sheets of polyhedra that are linked through cation−cation interactions with uranyl ions located between the sheets. CsFm possesses an unusually complex framework of vertex- and edge-sharing U6+ polyhedra that incorporates cation−cation interactions.