Abstract The distribution of scandium(III) at a tracer concentration was determined between chloroform with acetylacetone or thenoyltrifluoroacetone and 0.1 m aqueous perchlorate solutions at 25°C. The change in the distribution ratio of the metal ion with the change in the chelating acid concentration or with the change in the hydrogen-ion concentration was explained in terms of the extraction of the tris chelate complexes into the organic phase and the formation of the primary complexes in the aqueous phases. The equilibrium constants in these systems were determined graphically, by a curve-fitting method to be as follows: Kex=[ScA3]org[H+]3⁄[Sc3+][HA]3org K 1=[ScA2+]⁄[Sc3+][A−] (Remark: Graphics omitted.)