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  • 1 Swiss Federal Institute of Technology Institut d’électrochimie et de radiochimie CH-1015 Lausanne Switzerland
  • 2 University Chemical Laboratory Lensfield Road CB2 1EW Cambridge England
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The photochemical decomposition of (NH4)2TcCl6 in dilute HCl, HClO4 and H2SO4 solutions has been studied. Electrophoresis and spectrophotometry were used to identify TcCl 62− , 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 62− , 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%.