Neutron diffraction study of UO2SeO4 • 2D2O

A powdered sample of deuterated uranyl selenate dihydrate UO2SeO4 center dot 2D(2)O is studied by neutron diffraction. This compound crystallizes in monoclinic space group P2(1)/c; a = 6.974(1) angstrom, b = 8.289(2) angstrom, c = 11.664(2) angstrom, beta=92.319(6)degrees, Z = 4, R-f = 3.14, R-I = 5.53, chi(2) = 2.82. The main structural units of the compound are [UO2SeO4(D2O)(2)] chains propagating along [100]. These chains belong to the AT(3)M(2)(1) crystal-chemical group (A=UO22+, T3=SeO42-, and M-1 = D2O) of uranyl complexes. These chains are linked into a framework by a system of hydrogen bonds formed by water hydrogen atoms of one chain and uranyl oxygen atoms of another.