The aquation of hexachlorotechnetate(IV)

The photochemical decomposition of (NH₄)₂TcCl₆ in dilute HCl, HClO₄ and H₂SO₄ solutions has been studied. Electrophoresis and spectrophotometry were used to identify TcCl ₆ ^2? , TcCl₅ (H₂O)^?, cationic and uncharged species and TcO ₄ ^? . The yield of each species as a function of the time of uv irradiation was determined. The TcCl ₆ ^2? , yield decreases to zero after 50 h of irradiation. The TcCl₅(H₂O)^?, cationic and uncharged species and TcO ₄ ^? are formed in different proportions in the three acids. After 120 h of irradiation of the HCl solution the principal Tc species was the cationic one (≈70%) followed by the uncharged species (≈24%). In HClO₄ solution the cationic species (≈70%) was followed by TcO ₄ ^? , but in H₂SO₄ solution the uncharged species amounts to ≈90%.