Crystal structure of deloryite, Cu-4(UO2)[Mo2O8](OH)(6)

Deloryite, Cu-4(UO2)[Mo2O8](OH)(6), M = 946.10, monoclinic, space group C2/m, a = 19.94(1), b = 6.116(2), c = 5.520(3) Angstrom, beta = 104.18(5)degrees, V = 652.8(1) Angstrom(3), Z = 2, rho(c) = 4.78 g cm(-)3, lambda(Mo K alpha) = 0.71073 Angstrom, mu = 200.22 cm(-1), dimensions 0.15 x 0.1 x 0.1 mm(3), F(000) = 852, room temperature, R = 0.064 for 402 reflections with \F\ > 3 sigma(F). The crystal structure of deloryite, like its synthetic analogue as well as chemically and crystallographically related derriksite Cu-4(UO2)(SeO3)(2)(OH)(6), contains layers formed by distorted [Cu(O,OH)(6)] octahedra with shared edges. The octahedral layers are linked by columns, built up of alternating pseudotetragonal (UO6)-O-[2+4] bipyramids and pseudotrigonal (MoO5)-O-[4+1] bipyramids. Two MoO5 bipyramids with shared edge form [Mo2O8] dimers with Mo-Mo distances = 3.456(4) Angstrom. The five-fold coordination of Mo revealed leads to a different description of the structural model of deloryite with respect to the earlier XRD study of its synthetic analogue. (Mo2O8)-O-[4+1] dimers in deloryite replace the pairs of tetrahedra SeO(3)E (E = lone-pair electrons) in derriksite.