CRYSTAL-STRUCTURE OF THE COMPLEX NEPTUNYL(V) CHROMATE K3NPO2(CRO4)(2)

Crystal structure of K3NpO2(CrO4)(2) was determined using a CAD4 SDP a utodiffractometer (MoKalpha radiation, graphite monochromator, omega s canning). Crystal data: a = 7.42(1), b = 8.86(1), c = 8.81(1) Angstrom , alpha = 99.20(8)degrees, beta = 98.48(8)degrees, gamma = 100.96(10)d egrees, V = 552 Angstrom(3); space group <P(1)over bar>, Z = 2, d(calc ) = 3.72 g cm(-3), mu(MoKalpha) = 106 cm(-1), R = 0.101, and R(w) = 0. 145 for 622 independent reflections with I > 5 sigma(1) and sin Theta/ lambda > 0.20 Angstrom(-1). The crystal structure consists of anionic chains with the composition [NpO2(CrO4)(2)](3n-)(n), in which the coor dination polyhedra of Np atoms (pentagonal bipyramids) are linked by c ommon equatorial edges.