Study of thorium and cerium carbonate complexes. Determination of the stability constants of pentacarbonatothorate (IV) and dicarbonatocerate(IV) Ions, at pH 8.8.

A solvent extraction method, followed by neutron activation analysis of Th(IV) and Ce(IV) enabled the study of complexation equilibria and the determination of the stability constants (βc5) and (βc2) of the pentacarbonatothorate(IV) and dicarbonatocerate(IV) ions at pH 8.8. The values obtained at various ionic strengths (I) were log βc5 = 22.0 ± 0.2 (I 0.025 M), 21.6 ± 0.2 (I 0.050 M), 21.4 ± 0.2 (I 0.700 M) for the thorium complex, and log βc2 = 10.1 ± 0.2 (I 0.025 M), 10.8 ± 0.2 (I 0.050 M), 12.3 ± 0.2 (I 0.700 M) for the cerium complex. (orig.)