Abstract
The formal potentials of the Np(VI)/Np(V) couple E f in alkaline solutions were measured potentiometrically. In 1 M LiOH, NaOH, KOH, CsOH, and (CH3)4NOH, the potentials are equal to 0.163⊥0.004, 0.125⊥0.005, 0.112⊥0.005, 0.107⊥0.005, and 0.109⊥0.005 V, respectively. In solutions of MOH+MCl [M=Li, Na, K, Cs, and (CH3)4N] at the ionic strength of 1, the dependence of E f on log[OH−] is a straight line with a slope of 0.118⊥0.010, i.e., two OH− ions participate in the electrochemical reaction between Np(VI) and Np(V). Taking into account the well-known structure of Np(VI), it can be stated that Np(V) in solutions with [OH−]=1 M and less exists in the form of the NpO2(OH) −2 anion. In 2–4 M LiOH and 2–11 M NaOH or KOH, the potential decreases with increasing alkali concentration. In these media, the anion NpO2(OH) 2−3 is formed.
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Simakin, G.A., Matyashchuk, I.V., and Vladimirova, N.A., Radiokhimiya, 1973, vol. 15, no. 1, pp. 98–100.
Spravochnik khimika (Chemist’s Handbook), Moscow: Khimiya, 1964, vol. 3, p. 827.
Peretrukhin, V.F. and Alekseeva, D.P., Radiokhimiya, 1974, vol. 16, no. 6, pp. 836–843.
Ermakov, V.S., Peretrukhin, V.F., and Krot, N.N., Radiokhimiya, 1977, vol. 19, no. 2, pp. 253–255.
Gelis, A.V., Vanycek, P., Jense, M.P., and Nash, K.L., Radiochim. Acta, 2001, vol. 39, no. 9, pp. 565–571.
Smirnov-Averin, A.P., Kovalenko, G.S., Ermolaev, N.P., and Krot, N.N., Zh. Anal. Khim., 1966, vol. 21, no. 1, pp. 76–78.
Zielen, A.J. and Cohen, D. J. Phys. Chem., 1970, vol. 74, no. 2, pp. 394–405.
Bratsch, S.G., J. Phys. Chem. Ref. Data, 1989, vol. 18, no. 1, pp. 1–21.
Fricke, R. and Rohmann, C., Z. Electrochem. Angew. Phys. Chem., 1924, vol. 30, pp. 580–587.
Rabinovich, V.A. and Khavin, Z.Ya., Kratkii khimicheskii spravochnik (Abridged Chemical Handbook), Leningrad: Khimiya, 1978.
Mefod’eva, M.P., Krot, N.N., and Afanas’eva, T.V., Radiokhimiya, 1977, vol. 19, no. 2, pp. 245–249.
The Actinide Elements, Seaborg, G.T. and Katz, J.J., Eds., New York, 1954. Translated under the title Aktinidy, Moscow: Inostrannaya Literatura, Moscow, 1955, pp. 375–396.
Cohen, D. and Fried, S., Inorg. Nucl. Chem. Lett., 1969, vol. 5, no. 8, pp. 653–663.
Krot, N.N., Gel’man, A.D., Mefod’eva, M.P., et al., Semivalentnoe sostoyanie neptuniya, plutoniya, ameritsiya (Heptavalent State of Neptunium, Plutonium, and Americium), Moscow: Nauka, 1977.
Williams, C.W., Blaudeau, J.P., Sullivan, J.C., et al., J. Am. Chem. Soc., 2001, vol. 123, no. 18, pp. 4346–4347.
Visyashcheva, G.I., Volkov, Yu.F., Simakin, G.A., and Kapshukov, I.I., Radiokhimiya, 1984, vol. 26, no. 2, pp. 171–176.
Ermakov, V.S., Peretrukhin, V.F., and Krot, N.N., Radiokhimiya, 1977, vol. 19, no. 3, pp. 324–327.
Garnov, A.Yu., Krot, N.N., Bessonov, A.A., and Perminov, V.P., Radiokhimiya, 1996, vol. 38, no. 5, pp. 428–433.
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Original Russian Text © V.P. Shilov, A.B. Yusov, 2006, published in Radiokhimiya, 2006, Vol. 48, No. 1, pp. 22–27.
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Shilov, V.P., Yusov, A.B. Potential of the NP(VI)/Np(V) couple in solutions of various alkalis. Radiochemistry 48, 24–30 (2006). https://doi.org/10.1134/S1066362206010061
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DOI: https://doi.org/10.1134/S1066362206010061