Uranium Molybdates

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.