Crystal structure and electronic absorption spectrum of neptunoyl perchlorate tetrahydrate NpO2ClO4x4H2O

Crystal structures of NpO2ClO4x4H2O is determined. Crystallographic data are as follows: a = 8.252(3), b = 5.736(2), c = 9.786(3)A, β 108.25 (3), sp.gr. P21, Z = 2, dcol = 3.20 g/cm3, R = 0.029 and Rω = 0.038. The structure is composed of alternating [NpO2x4H2O]nn+ cation layers and anion layers, formed by extrasphere perchlorate ions. Each NpO2 group represents monodentate ligand for neighbouring group; this results in formation of zigzag neptunoyl chains. The coordination-bound water molecular supplement the number of Np atoms up to 7; the Np coordination polyhedron represents a pentagonal bipyramid. The compound structure peculiarities in its electron absorption spectrum are considered. 6 refs.; 3 figs.; 3 tabs