On the mechanism of the electrochemical reduction of TcO 4 −1 ion on platinum cathode in sulphuric acid solutions

Abstract

Electroreduction of oxygen-containing anions of the elements of VII group of periodic table, in particular, technetium is a very complicated process. The structure of electron shells of technetium 4d6 5s1 (s9/2), allows some oxidation states from +7 to −1, and shows the tendency to hydrolysis, disproportionation and to complex formation. Heptavalent state with d0-electron configuration and low tendency to reduction is characteristic for technetium and rhenium. We have studied the products of electroreduction of ion TcO 4 − from sulphurous acid solutions of pertechnetate on platinum cathode using electrophoresis, methods of classic preparation chemistry, electron and vibratory spectroscopy. As a result we have succeeded in the isolation of the products of electrochemical reactions, identification and explaining some features of the process connected with the formation of metalic technetium and intermediate complex forms of reduced technetium.