Medium effects on reactions of the carbonate radical with thiocyanate, iodide, and ferrocyanide ions

Results are presented which show that there is no pH dependence of the carbonate radical reactivity toward SCN-, I-, and Fe(CN)(6)(4-) above pH 8.5. It is demonstrated that observations in the literature on these reactions which have been interpreted to show a pK(a) of 9.5 for the carbonate radical, in disagreement with other reports that the radical is not protonated in/this pH region, can Ire explained by the medium effects. It is also shown that previous studies of the reaction between carbonate radical and thiocyanate are in error, and the mechanism of this reaction is elucidated. Published by Elsevier Science Ltd.