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 o f Th(IV) and Ce(IV) enabled the study of complexation equilibria and t he determination of the stability constants (beta(5)(c)) and (beta(2)( c)) of the pentacarbonatothorate(IV) and dicarbonatocerate(IV) ions at pH 8.8. The values obtained at various ionic strengths (I) were log b eta(5)(c) = 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 beta(2)(c) = 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.