Uranyl molybdate, UO2MoO4, is obtained as a white amorphous precipitate when ammonium molybdate is added to uranyl nitrate solution in the dark. It is reduced to uranous molybdate, U(MoO4)2, becoming green by the action of ethyl or methyl alcohol or acetic acid, and dissolves in mineral acids with a yellowish-green fluorescence. When exposed to sunlight, uranyl molybdate gradually becomes golden-yellow in colour, and the product is no longer soluble in nitric acid, nor is it reduced by alcohol. The salt is strongly radioactive.
The paramolybdate, 3UO3.7MoO3, is obtained as a curdy precipitate by the addition of uranyl nitrate to ammonium paramolybdate solution. On drying it yields a yellow amorphous powder, which dissolves in acids with a yellowish-green fluorescence. It is hydrolysed by water to uranyl hydroxide and molybdic acid. |