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 TcCl62-, TcCl5(H2O)-, cationic and uncharged species and TcO4-. The yield of each species as a function of the time of uv irradiation was determined. The TcCl62-, yield decreases to zero after 50 h of irradiation. The TcCl5(H2O)-, cationic and uncharged species and TcO4- 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 (approximately 70%) followed by the uncharged species (approximately 24%). In HClO4 solution the cationic species (approximately 70%) was followed by TcO4-, but in H2SO4 solution the uncharged species amounts to approximately 90%. (author)