Abstract
The carbonate complexation reactions of Cm(III) were studied by time-resolved laser fluorescence spectroscopy in 0–6 m NaCl at 25°C. The ionic strength dependence of the stepwise formation constants for the carbonato complexes Cm(CO3) 3−2nn with n = 1, 2, 3, and 4 is described by modeling the activity coefficients of the Cm(III) species with Pitzer's ion-interaction approach. Based on the present results and literature data for Cm(III) and Am (III), the mean carbonate complexation constants at I = 0 are calculated to be: log β o101 =8.1 ±0.3, log β o102 =13.0 ± 0.6, log β o103 =15.2 ± 0.4, and log β o104 =13.0 ± 0.5. Combining these equilibrium constants at infinite dilution and the evaluated set of Pitzer parameters, a model is obtained, that reliably predicts the thermodynamics of bivalent actinide An(III) carbonate complexation in dilute to concentrated NaCl solution.
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Fanghänel, T., Könnecke, T., Weger, H. et al. Thermodynamics of Cm(III) in Concentrated Salt Solutions: Carbonate Complexation in NaCl Solution at 25°C. Journal of Solution Chemistry 28, 447–462 (1999). https://doi.org/10.1023/A:1022664013648
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DOI: https://doi.org/10.1023/A:1022664013648