No abstract available

[en] The photochemical aquation of K₂TcBr₆ in 2M HBr, 1M HClO₄ and 1M H₂SO₄ was studied. The absorption spectra of the various Tc(IV) species were measured after the electrophoretic separation. The spectrophotometric changes and the yield of each species were determined as a function of the UV irradiation time. After 25 hours of irradiation of HBr and HClO₄ solutions, the main species were the cationic ones (∼ 80%) but in H₂SO₄ solution the neutral species reached a yield of 90%. The oxidation of Tc(IV) species to TcO₄^- proceeded more rapidly and extensively in HClO₄ than in HBr and H₂SO₄. (author) 6 refs.; 6 figs

No abstract available

No abstract available

[en] The influence of matrix physical state on the ^95mTc decay in M₂^99(95m)TcX₆ was studied. In the solid the ^95gTc retention was constant (83%). The decrease of matrix amount led to a decrease of the ^95gTc retention to 34%. This value remained constant upon further decrease of the matrix. In frozen solutions, the ^95gTc retention was found to be 18-20%. In the same range of salt concentrations, the retention in solution was found to be 3%. The increase of salt concentration to 2 x 10^-2M led to an increase of retention in frozen solutions but did not affect its value in solution. (author) 6 refs.; 4 figs

[en] The formation of the salts of (TcOBr₅)^2- and (TcOBr₄)^-were investigated with the following cations: NH₄, K⁺, Rb⁺, Cs⁺, Et₄N⁺ and Me₄N⁺. Results are presented for the UV-vis. and infrared spectra of these salts. (UK)

[en] The solvent extraction of Tc(IV) and Tc(VII) by isoamyl alcohol has been studied. The TcCl₆^2- and TcO₄^- ions are both extracted from 3M H₂SO₄ solution but hydrolyzed Tc(IV) species are not. This permits the separation of the two valence states of technetium. The air oxidation of carrier-free hydrolyzed sup(99m)Tc(IV) may be limited by the presence of ⁹⁹Tc carrier in the same chemical form. Paper chromatography and electrophoresis were used to identify TcCl₆^2-, TcO₄^- and hydrolyzed species. It was also found that the hydrolyzed ReCl₆^2- can reduce TcO₄^- to TC(IV). (author)

[en] The authors study the sup(95m)Tc decay in a K₂sup(99(95m))TcF₆ solid matrix and in solutions and compare the results with those obtained on K₂sup(99(95m))TcCl₆. (Auth.)

[en] The chemical effect of the (n,γ) reaction on Re₂(CO)₁₀ was further investigated. Chromatography was found to be the most suitable method for the separation of various chemical species. (author)

[en] The products found upon solution following isomeric transition in solid K₂sup(95m/99)TcF₆ and for isomeric transition in aqueous solutions of the hexafluorotechnetate(IV) have been found to be qualitatively the same. They correspond to the products expected from the reaction of TcF₅^-, TcF₄ etc. with water. In the solid these fragments are thermalized before reaction with water; in solution they may react while kinetically excited. It has been shown that after isomeric transition in solid K₂TcF₆ the product distribution is independent of the temperature at which the solid is dissolved for analysis (over span of 30⁰). Nor is the distribution sensitive to the composition of the solution, in which the solid is dissolved. For isomeric transition in solution the results are quite different. The sup(95g)Tc distribution is now temperature dependent. In addition the distribution changes considerably with the composition of the solution. (Auth.)