Metathetical routes to uranium and thorium oxides and nitrides

Oxides and nitrides of uranium and thorium are commonly prepared by combining the elements at high temperature, which is a potentially hazardous and expensive procedure or by thermolysis of nitrate salts. An extension of the solid state metathesis reaction to the synthesis of uranium and thorium oxides and nitrides is reported in this letter. This method of preparation has already been demonstrated for transition metal and lanthanide particles where the metal halide and an alkali metal particle are combined at a low initiation temperature. The reaction is extremely exothermic generating sufficient heat to produce a crystalline product. Uranium and thorium tetrachlorides have been sealed with Li2O or Li3N under vacuum and heated to 5000C. Powder X-ray diffraction was used to identify the phases present in the reaction products. (1 figure, 1 table, 12 references). (UK)