Solid-state actinide acid phosphites from phosphorous acid melts

Reaction of UO3 and H3PO3 at 100 °C and subsequent reaction with DMF produces crystals of (NH2(CH3)2)[UO2(HPO2OH)(HPO3)] with a layered structure. Reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup and further solution-state reactions result in the crystallization of the actinide acid phosphites An(HPO2OH)4 (An=U, Th), with a three-dimensional network structure, and the mixed acid phosphite-phosphite U(HPO3)(HPO2OH)2(H2O)2·(H2O) with a layered structure.