Lead Metatungstate, PbW₄O₁₃

Lead Metatungstate, PbW₄O₁₃.5H₂O, is obtained as a white flocculent precipitate by double decomposition. It is insoluble in water; soluble in hot nitric acid. However, by the addition of lead nitrate to an alkali tungstate solution, a crystalline precipitate has been obtained, of composition PbW₄O₁₃.Pb(NO₃)₂.10H₂O. This is only very slightly soluble in water, and when heated it loses 7H₂O.

Lithium Metatungstate cannot be prepared by either of Scheibler's methods, i.e. by neutralising metatungstic acid with lithium carbonate, or by adding lithium sulphate to a solution of barium metatungstate. The anhydrous tetratungstate has been prepared.