Sodium Orthoxymonothiovanadate, Na3VSO3.10H2O, has been obtained in orange-yellow crystals by the action of sodium hydrosulphide on sodium pyrovanadate.
The action of hydrogen sulphide at high temperatures on sodium pyrovanadate gives rise to sodium pentathiopyrovanadate, Na4V2S5O2, which is a hygroscopic substance very similar in its colour and lustre to potassium permanganate.
Thiovanadates of the heavy metals have proved difficult to isolate; addition of solutions of salts of zinc, manganese, copper and silver to a solution of ammonium thiovanadate gives precipitates which consist of sulphides or thiovanadates of the metals, or mixtures of both. A black, crystalline lead salt of the probable composition Pb2V2S2O5, lead dithiopyrov anadate, has, however, been obtained. |