Model of the crystal structure of Np(VI) sulfate with dimethyl sulfoxide, NpO2SO4 center dot 2SO(CH3)(2)center dot H2O

A new complex compound, neptunium(VI) sulfate, was grown from aqueous solut ions and studied by the methods of X-ray structure analysis. The model of t he crystal structure was determined, by direct methods within the sp. gr. P 2(1) and was refined in the anisotropic approximation (R = 6.2%, 1044 indep endent reflections). The structure is built by tetragonal and hexagonal Np bipyramids. A hexagonal bipyramid can be considered as a polyhedron derived from a pentagonal bipyramid, in which one equatorial O atom is replaced by two atoms located above and below the equatorial plane. The polyhedra are linked in chains through S-tetrahedra. The chains are linked into a three-d imensional framework by hydrogen bonds with the participation of DMSO group s. (C) 2000 MAIK "Nauka/Interperiodica".