Aqueous uranyl complexes. 3. Potentiometric measurements of the hydrolysis of uranyl(VI) ion at 25{degrees}C
- Oak Ridge National Lab., TN (United States)
Potentiometric titrations of uranyl(VI) solutions were conducted using a standard glass/calomel electrode combination over the pH range 3 to 12 at 0.1 mol-kg{sup {minus}1} ionic strength with tetramethylammonium trifluoromethanesulfonate as the supporting electrolyte. The electrodes were calibrated directly on the hydrogen ion concentration scale during the initial stage of each titration. The species, UO{sub 2}{sup 2+}, (UO{sub 2}){sub 2}(OH){sub 2}{sup 2+}, (UO{sub 2}){sub 3}(OH){sub 5}{sup +}, (UO{sub 2}){sub 3}(OH){sub 7}{sup {minus}}, (UO{sub 2}){sub 3}(OH){sub 8}{sup 2-}, and (UO{sub 2}){sub 3}(OH){sub 10}{sup 4-} identified in an earlier Raman study were compatible with the analysis of the titration data. Based on this analysis and application of the extended Debye-Hueckel treatment, the polynuclear species indicated above were assigned overall formation constants at 25{degrees}C and at infinite dilution of -5.51{plus_minus}0.04, -15.3{plus_minus}0.1, -27.77{plus_minus}0.09, -37.65{plus_minus}0.14, and -62.4{plus_minus}0.3, respectively. The results are discussed in reference to hydrolysis quotients reported in the literature for the first three species. Formation quotients for the last two species have not been reported previously.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 255273
- Journal Information:
- Journal of Solution Chemistry, Vol. 24, Issue 12; Other Information: PBD: Dec 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
The potentiometric determination of stability constants for zinc acetate complexes in aqueous solutions to 295C
Aluminum speciation and equilibria in aqueous solution: III. Potentiometric determination of the first hydrolysis constant of aluminum(III) in sodium chloride solutions to 125[degrees]C