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Self-Assembly of a Polar Open-Framework Uranyl Vanadyl Hexaoxoiodate(VII) Constructed Entirely from Distorted Octahedral Building Units in the First Uranium Hexaoxoiodate: K 2 [(UO 2 ) 2 (VO) 2 (IO 6 ) 2 O]·H 2 O

2003; American Chemical Society; Volume: 42; Issue: 7 Linguagem: Inglês

10.1021/ic026290x

1520-510X

Richard E. Sykora, Thomas E. Albrecht‐Schmitt,

Nuclear materials and radiation effects

The reaction of UO(3) with V(2)O(5) and KIO(4) under mild hydrothermal conditions produces K(2)[(UO(2))(2)(VO)(2)(IO(6))(2)O].H(2)O (1) in the form of orange acicular crystals. The structure of 1 consists of UO(6), VO(6), and IO(6) distorted octahedra that are assembled into a polar, open-framework structure. The distorted VO(6) and IO(6) octahedra edge-share to form chains that run down the c-axis. Each VO(6) octahedron also shares a vertex with an adjacent vanadium atom to link the chains together into a ribbon. The IO(6) units also partake in corner-sharing with the UO(6) units to create interconnected elliptical tubes. The major channels in 1 are filled with K(+) cations and water molecules. The polarity of this compound is caused by alignment of distorted vanadyl hexaoxoiodate ribbons and UO(6) trapezoidal bipyramids resulting in a large second-harmonic generation response of 300 times that of alpha-quartz. Crystallographic data: 1, orthorhombic, space group Pba2, a = 9.984(2) A, b = 16.763(3) A, c = 4.977(1) A, Z = 4 (T = 193 K).