Effect of ionic strength on the activation parameters of fast electron-transfer reactions. [Reactions of V(II)--Fe(III) and U(III)--Fe(III)]
The activation parameters of the V(II)--Fe(III) and U(III)--Fe(III) reactions were determined as a function of ionic strength in perchlorate media. Contrary to expectations, the values of ..delta..S/sup + +/ for these reactions were found to be independent of ionic strength, the changes in rate constant being reflected exclusively in the values of ..delta..H/sup + +/. Plausible explanations for these observations are discussed.