Straightforward reductive routes to air-stable uranium(III) and neptunium(III) materials

Studies of trivalent uranium (U(3+)) and neptunium (Np(3+)) are restricted by the tendency of these ions to oxidize in the presence of air and water, requiring manipulations to be carried out in inert conditions to produce trivalent products. While the organometallic and high-temperature reduction chemistry of U(3+) and, to a much smaller extent, Np(3+) has been explored, the study of the oxoanion chemistry of these species has been limited despite their interesting optical and magnetic properties. We report the synthesis of U(3+) and Np(3+) sulfates by utilizing zinc amalgam as an in situ reductant with absolutely no regard to the exclusion of O2 or water. By employing this method we have developed a family of alkali metal U(3+) and Np(3+) sulfates that are air and water stable. The structures, electronic spectra, and magnetic behavior are reported.