The structure of UO2DAsO4.4D2O at 4 K by powder neutron diffraction

The low-temperature structure of deuterated uranyl hydrogenarsenate tetrahydrate, UO2DAsO4.4D2O, has been determined in space group P-1 with a = 7.1644(1), b = 7.1124(1), c = 17.5537(3) A, α = 90.187(3), β = 89.947(4), γ = 90.003(4)0 and Z = 4 from profile analysis of a powder neutron diffraction pattern at 4 K. The profile arising from 2098 overlapping reflections, including 41 reflections from contaminating ice, was refined to an Rsub(wp) of 4.19 using a new computer program which allows the simultaneous refinement of more than one phase. The structure consists of chains of H4O2 dimers and H5O2+ ions which alternate between layers of UO22+ and AsO43- ions. (Auth.)