Antimony Tungstates

The normal salt appears to be formed on mixing solutions of normal sodium tungstate and tartar-emetic as a white precipitate which is decomposed by washing with water. The acid salt, Sb₂O₃.5WO₃.4H₂O, is formed as a yellow precipitate on mixing solutions of sodium ditungstate and tartar-emetic in presence of alcohol; it dissolves readily in water without decomposition. Another acid salt, Sb₂O₃.6WO₃.8H₂O, is obtained as a white precipitate by treating a solution of sodium tritungstate in a similar manner.