Radiolytic yield of U(IV) oxidation into U(VI): a new mechanism for U(V) reactivity in acidic solution.
The yields of the radiolytic oxidation of U(IV) and of the U(VI) formation, measured by spectrophotometry, are found to be the same (G(-U(IV))(N2O) = G(U(VI))(N2O) = 8.4 x 10(-7) mol J(-1)) and almost double the H(2) formation yield (G(H(2)) = 4.4 x 10(-7) mol J(-1)) in the (60)Co gamma radiolysis of N(2)O-aqueous solutions in the presence of 2 mol L(-1) Cl(-) at pH = 0 (HCl). According to the mechanism of U(IV) radiolytic oxidation, we show that under the conditions of our experiments the U(V) ions do not disproportionate, but undergo a stoichiometric oxidation into U(VI) by H(+) with forming H(2).
Atinault
E
E
Laboratoire de Chimie Physique/ELYSE, CNRS-Université Paris-Sud, Orsay, France.
De Waele
V
V
Belloni
J
J
Le Naour
C
C
Fattahi
M
M
Mostafavi
M
M