Diperoxo Pertechnetic Acid Characterized by Spectroscopic and Quantum Chemical Studies

The reaction of Tc(+7) with H 2 O 2 has been studied in HNO 3 and the speciation of technetium was performed by UV/Vis spectroscopic analysis. UV/Vis measurements show that for HNO 3 concentrations of more than 7 M and H 2 O 2 concentrations of 4.25 M , Tc(+7) reacts immediately and red solutions are obtained, whereas no reaction occurs at H 2 O 2 concentrations of 0.1 M . The UV/Vis spectra of the red solutions exhibit a single band centered at 500 nm that is attributed to a Tc(+7) peroxo species. The nature of the Tc(+7) peroxo species was investigated by computational methods. The structures and electronic spectra of the putative species Tc(O 2 ) 4 – , TcO(O 2 ) 3 – , TcO 3 (O 2 ) – , TcO(O 2 ) 2 (H 2 O)(OH), and TcO 2 (O 2 )(H 2 O) 2 (OH) were studied by first principles methods. Calculations show these species to be stable; their calculated spectra were compared to the experimental spectrum and the results are consistent with the presence of diperoxo pertechnetic acid, i.e., TcO(O 2 ) 2 (H 2 O)(OH).