Aquation of K2 TcBr6 in dilute acid solutions

The photochemical aquation of K₂ TcBr₆ in 2M HRr, 1M HClO₄ and 1M H₂SO₄ has been studied. The absorption spectra of the various Tc(IV) species were measured after the electrophoretic separation. The spectrophotometric changes and the yield of each species as a function of the UV irradiation time were determined. After 25 hours of irradiation of HBr and HClO₄ solutions the main species were the cationic ones (80%) but in H₂SO₄ solution the neutral species reached a yield of 90%. The oxidation of Tc(IV) species to TcO₄^– proceeded more rapidly and extensively in HClO₄ than in HBr and H₂SO₄.