Measurement of Disproportionation Rates at the Dropping Mercury Electrode

Abstract

Vol. 75 to the electrode at a different rate than the symmetrical trans form. It follows that the migration current, and hence the limiting current, would be different for the cis ion than for the trans,2SThe situation in the absence of supporting electrolyte is complicated by the formation of electrolyte (nitrite ions, for example) during the reduction, as well as by stirring effects associated with maxima which may not completely disappear even at more negative potentials. Absolute values for limiting currents are, therefore, not reproducible.Experimentally, the cri-dinitrotetramminecobalt-(III) chloride has consistently given slightly higher limiting current values than the corresponding trans isomer in the absence of supporting elec-(28) H.

Detection of uranium(VI) in aqueous solution by a calix[6]arene modified electrode

“…In a systematic study using a gold electrode, the effect of acidity on the magnitude of redox waves of U(VI)/U(V) was reported. It was found that in strongly acidic solutions (i.e., pH 62) the decomposition of U(V) was enhanced and therefore the anodic wave of U(V) to U(VI) decreased [27,[31][32][33][34]. Kuta and Yeager studied the redox mechanism of uranyl on a gold electrode in perchlorate solution, and thoroughly reported on similar findings [35,36].…”

“…While these findings are not simple to interpret, it is likely to assume that a portion of the uranium(IV) product from the disproportionation of UO þ 2 reaches the electrode and is oxidized. This assumption is based on several past publications [31][32][33][34] …”

“…The electrochemistry of UO 2þ 2 has been extensively studied in the past, primarily by polarography, published as early as the 1940s [24][25][26][27][28][29][30][31][32][33]. Two [25][26][27]29,30] or three [24,28] distinctive waves have been associated with the reduction of uranyl: the first wave was assigned to the reversible reduction of U(VI) to U(V), while the second corresponded to the further reduction of U(V) to U(IV).…”

Electroreduction of uranyl ion in aqueous calcium nitrate solutions

“…In less acidic solutions the situation is simplified because the disproportionation of U(V) does not take place (13), but studies in weakly acid to neutral aqueous media (13,14) are few.…”

“…The reduction of U(V1) has been extensively studied in aqueous media by different electrochemical methods (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14).2 Most of these studies have been carried out in acidic (HCIO,, HCl, H2S04, HN03) media (2-1 1). In sufficiently acidic solution, the reduction mechanism (12) is that uranyl is reduced in a one-electron step and that the resulting U(V) species disproportionates, regenerating U(W).…”