Direct potentiometric determination of the formal potential of the Bk(III)-Bk(IV) couple in sulfuric acid

Stokely, J.R.; Baybarz, R.D.; Shults, W.D.

doi:10.1016/0020-1650(69)80005-x

Cited by 13 publications

(8 citation statements)

References 7 publications

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“…Thus, it appears that under the present conditions the actual mechanism must involve an equilibrium between (at least) two Bk(IV) species. The quality of the fit is very sensitive to variations in any of the electrochemical parameters ES'b, k°i B , and a A B ) for Steps (2) and (3). Variations of ± 10% in any of these parameters will significantly alter the general shape and peak potentials and currents of the voltammograms.…”

Section: Potential (V/sce)mentioning

confidence: 98%

“…Most of these studies have been concerned primarily with accurately determining the formal potential of the couple and examining the influence of acid concentration on the potential. Such studies have been reported for solutions of the weakly complexing acids HN0 3 [4, 6 -8, 10, 14] and HC10 4 [4,6,10,14], and the moderately complexing acids H 2 S0 4 [2,3,9,14] and H 3 P0 4 [4,12,14]. Much less attention has been focused on the characterization of Bk(III) and Bk(IV) in strongly complexing and/or near-neutral aqueous media.…”

Section: Introductionmentioning

confidence: 94%

“…Four factors were considered in judging qualitatively the degree of the fit between the experimental and simulated voltammograms. These were (1) the peak potentials of the two cathodic peaks, E^' and E^', (to the extent that these peak positions could be approximated), (2) the peak potentials of the two anodic peaks, E^' and E^', (3) the ratio of the peak currents of the two cathodic waves (i^ and i^'), and (4) the ratio of the peak currents of the two anodic waves, (iji'and i (2) ). Attention was focused on qualitatively reproducing the values of these parameters at only three scan rates: 10, 50, and 100 mV/s.…”

Section: Potential (V/sce)mentioning

confidence: 99%

“…For the pH 10.0 solution, the criterion for establishing the best fit of the simulated data to the experimental data was a minimum in the weighted sum-of-squares-of-differences, AX 2 = Σ ν (X expt ¡ -Xsimulated) 2 ' Wt, where X = AEp, AE p/2 , or Ep,. and Wt = 0.5 for the data at ν = 10,20,200, and 250 mV/ s and 1.0 for the data at other ν values.…”

Section: Case 1 : Simple Heterogeneous Electron Transfermentioning

confidence: 99%

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Voltammetric Investigation of the Berkelium(IV/III) Couple in Concentrated Aqueous Carbonate Solutions

et al. 1990

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This report describes the results from the first cyclic voltammetric investigation of the 249 Bk(IV/III) redox system in strongly complexing aqueous solutions. For this study concentrated carbonate solutions of varying pH were chosen as the complexing media. Diverse voltammetric behavior was observed over a total carbonate concentration range of 2 to 5 M and a pH range from 9.5 to 13.5. Because of the complexity of the voltammetry, digital simulations of the experimental results were required to analyze the behavior more thoroughly. The simplest voltammetric behavior was observed in 2 M carbonate at pH 10.0 and 13.5. Here single quasi-reversible Bk(IV/III) couples were observed. The electrochemical parameters at pH 10.0 are E 1/2 = -0.021 V/SCE, kO/D^2 = 0.63 s" 1 ' 2 , and α = 0.32. Those at pH 13.5 are +0.20 V/SCE, 0.03 s" 1 ' 2 , and 0.3 respectively. Direct evidence for the presence of an equilibrium between two (or more) Bk(IV) species with differing reduction potentials was found for several solution conditions. This behavior was quantitated for the system in 2 M carbonate at pH 11.7 by proposing a combined chemical/electrochemical mechanism and testing with digital simulations. The results indicate that the two Bk(IV) species are the same as those found at pH 10.0 and 13.5. Finally, non-diffusive electrochemical behavior was observed for several solution conditions. This appears to be consistent with the oxidation of a Bk(III) species which is either precipitated or adsorbed on the Pt electrode surface.

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Section: Potential (V/sce)mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 94%

Section: Potential (V/sce)mentioning

confidence: 99%

Section: Case 1 : Simple Heterogeneous Electron Transfermentioning

confidence: 99%

See 2 more Smart Citations

Voltammetric Investigation of the Berkelium(IV/III) Couple in Concentrated Aqueous Carbonate Solutions

et al. 1990

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“…For other media (such as solutions of H 2 S0 4 , H3PO4, K 2 C0 3 ), fragmentary, sometimes conflicting, findings are described [4][5][6][7], In particular, the data for values E f in sulfuric acid solutions, which were measured in the range of concentrations of sulfuric acid between 0.05 and 2M [4][5][6], are differed on 45 mV. Because sulfuric acid solutions are a convenient medium for obtaining Bk(IV) and are often employed in analytical practice [8], it is essential to have reliable data on the values of E f in solutions of various concentrations of H 2 S0 4 .…”

Section: Introductionmentioning

confidence: 99%