CRYSTAL-STRUCTURE OF THE COMPLEX NEPTUNIUM(V)MOLYBDATE CS-2(NPO2)(2)MO2O8

Crystal structure of Cs-2(NpO2)(2)Mo2O8 (I) (CAD4 autodiffractometer, lambda MoKalpha graphite monochromator) has been determined. Crystal d ata: a = 7.302(5), b = 8.837(4), c = 10.868(8) Angstrom, beta = 104.68 (6)degrees, V = 678.5 Angstrom(3); space group P2(1)/c Z = 4, d(calc) = 5.50 g cm(-3), mu(MoKalpha) = 207 cm(-1); R = 0.049, R(omega) = 0.05 9 [from 671 reflections with sin theta/lambda > 0.15 Angstrom(-1) and I > 4 sigma(I)]. The crystal of compound I is built up from [(NpO2)(2) (Mo2O8)](2n-)(n) anionic layers with Cs+ cations between them. Compoun d I is isostructural to artificial analogs of carnotite K-2(UO2)(2)V2O 8 and Cs-2(UO2)(2)V2O8. The structures of Mo2O84- and V2O86- anions ha ve been compared.