Author/Authors :
Poineau، نويسنده , , Frederic and Burton-Pye، نويسنده , , Benjamin P. and Maruk، نويسنده , , Alesya and Kirakosyan، نويسنده , , Gayane and Denden، نويسنده , , Ibthihel and Rego، نويسنده , , Daniel B. and Johnstone، نويسنده , , Erik V. and Sattelberger، نويسنده , , Alfred P. and Fattahi، نويسنده , , Massoud and Francesconi، نويسنده , , Lynn C. and German، نويسنده , , Konstantin E. and ، نويسنده ,
Abstract :
The speciation of Tc(+7) was performed in HClO4 and HNO3 by 99-Tc NMR, UV–Vis and XAFS spectroscopy. The speciation of Tc(+7) depends on the concentration and strength of the acid. Pertechnetic acid, HTcO4, forms above 8 M HClO4 while in concentrated HNO3, [TcO4]− is still the predominant species. EXAFS spectroscopy shows that the structure of HTcO4 in HClO4 is similar to the one in H2SO4. The reactivity of Tc(+7) was analyzed in the frame of the partial charge model. The partial charge calculated on the Tc atoms (ΔTc) indicates that HTcO4 (ΔTc = +057) is more electrophilic than [TcO4]− (ΔTc = +0.52). The difference in the oxidizing properties between [TcO4]− and HTcO4 is given from the reaction of these species with 12 M HCl(aq). In 13 M sulfuric acid HTcO4 is reduced to Tc(+5) while [TcO4]− is not reduced in 6 M H2SO4.
Keywords :
Speciation , perchloric acid , Technetium , Nitric acid
