CRYSTAL-STRUCTURE OF THE COMPLEX NEPTUNYL(V) CHROMATE CSNPO2CRO4-CENTER-DOT-2H(2)O

Crystal structure of CsNpO(2)CrO(4)2H(2)O has been determined using a CAD4 autodiffractometer (MoKalpha radiation, graphite monochromator, o mega/2 theta scanning). Crystal data: a = 7.359(3), b = 7.523(2), c = 15.457(3) Angstrom; space group Pnma, Z = 4, d(calc), = 4.30 g cm(-3), p(MoKalpha) = 163 cm(-1), R = 0.043, and R(w) = 0.057 for 1103 reflec tions with I > 5 sigma(I) and sin theta/lambda > 0.10 Angstrom(-1). Th e crystal structure consists of infinite chains with the composition [ NpO2CrO4(H2O)](n-)(n), in which the coordination polyhedra of Np atoms (pentagonal bipyramids) are linked by common edges through the bridgi ng chromate ions. The IR and electronic absorption spectra are discuss ed.