Thallium Tungstates

The normal thallous salt, Tl₂WO₄, is precipitated when solutions of normal sodium tungstate and a thallous salt are mixed, or when a boiling solution of tungstic acid is neutralised with thallous carbonate. It yields highly refractive, hexagonal microcrystals. Thallic tungstate has not been prepared.

Thallous paratungstate, 5Tl₂O.12WO₃.9H₂O, is obtained, on adding excess of thallous sulphate solution to a solution of sodium paratungstate, as a white amorphous precipitate, insoluble in water, soluble in alkalies.