Orthopervanadates

The ammonium salt, (NH4)3VO6.2½H2O, is obtained by dissolving ammonium metavanadate in excess of concentrated ammonia solution, cooling to 0° C., adding 30 per cent, hydrogen peroxide, and then precipitating with alcohol. The product, after washing with ether and drying, is pale blue, and probably has the constitution With large excess of hydrogen peroxide an indigo-blue salt which contains more oxygen, probably VO2(OH)(O.ONH4)2, is obtained.

Potassium Orthopervanadate, K₃VO₆,2½H₂O