caa a22 4500 378897195 CHVBK 20180305123509.0 cr unu---uuuuu 161128e20041201xx s 000 0 eng 10.1524/ract.92.12.869.55104 doi (NATIONALLICENCE)gruyter-10.1524/ract.92.12.869.55104 Hydrolysis of Np(IV) and Pu(IV) and their complexation by aqueous Si(OH)4 [Elektronische Daten] [A. B. Yusov, A. M. Fedosseev, C. H. Delegard] The hydrolysis and interaction of Np(IV) and Pu(IV) with orthosilicic acid, Si(OH)4, were studied in 0.1-1.0M ionic strength aqueous solutions. Spectrophotometry was used to study these reactions at about 10-4M Np(IV) and Pu(IV) concentrations. The first hydrolysis constants, Khydr, agree with the majority of earlier spectrophotometric and potentiometric data. The absorption spectra of NpOH3+ and PuOH3+ were obtained by spectral deconvolution. Reasons to explain the overestimation of Khydr obtained by other methods [by extraction of trace amounts of Np(IV) and Pu(IV) and by solubility] are discussed. Formation of the complexes NpOSi(OH)33+ and PuOSi(OH)33+ is demonstrated in the presence of 0.005-0.016M Si(OH)4 in the p[H+] range 1.0-2.2 and 0.3-1.4, respectively. Measured values of equilibrium constants of the reaction M4+ + Si(OH)4 ↔ MOSi(OH)33+ + H+ at ionic strength I=1.0 are lg K1 = 0.41±0.02 and 1.04±0.04, respectively, for Np(IV) and Pu(IV). The stability constants of the NpOSi(OH)33+ and PuOSi(OH)33+ complexes, recalculated to zero ionic strength, are lg β10 = 11.2 and 11.8, respectively. The correlation between Khydr and K1, as observed for all earlier studied metal ions, also occurs for both Np(IV) and Pu(IV). © 2004 Oldenbourg Wissenschaftsverlag GmbH Laboratory techniques, experiments nationallicence Analytical chemistry nationallicence Inorganic chemistry nationallicence Yusov A. B. aut Fedosseev A. M. aut Delegard C. H. aut Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/12/2004(2004-12-01), 869-881 0033-8230 92:12/2004<869 2004 92 ract https://doi.org/10.1524/ract.92.12.869.55104 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/ract.92.12.869.55104 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yusov A. B. aut NATIONALLICENCE 700 1- Fedosseev A. M. aut NATIONALLICENCE 700 1- Delegard C. H. aut NATIONALLICENCE 773 0- Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/12/2004(2004-12-01), 869-881 0033-8230 92:12/2004<869 2004 92 ract CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter