| Ammonium Pyroxyhexathiovanadate, (NH4)4V2S6O, is deposited in red crystals when hydrogen sulphide is passed into a solution of ammonium metavanadate in ammonium hydroxide of higher specific gravity than 0.898 and the mixture kept for several months at a low temperature. The corresponding potassium salts, K4V2S6O.3H2O and K4V2S6O.1½H2O, are prepared in a similar manner. The normal potassium orthothiovanadate, K3VS4, has not been separately isolated, although mixtures which most probably contain it, together with the normal ammonium salt, have been prepared. |