Tantalum Sulphates

No sulphates of tantalum have been definitely prepared. A fused mass of tantalum pentoxide and potassium hydrogen sulphate after extraction with boiling water is crystalline and contains the sulphate radical, and it has been assumed that a sulphate of tantalum is present. After drying at 100° C. the product in one case had the composition 3Ta₂O₅.SO₃.9H₂O, but this was most probably the hydrolytic decomposition product of an unstable sulphate present in the melt or in solution.