Collect. Czech. Chem. Commun. 1988, 53, 506-514

Polarographic study of the mixed complexes of Cd(II) with oxalate and malonate ions

Cesar Rodríguez-Placeres, Graciliano Ruiz-Cabrera, Ana Alloza and Agustin Arévalo

Department of Physical Chemistry University of La Laguna, Tenerife, Canary Islands (Spain)


The coordinated mixed Cd(II)-oxalate-malonate system has been polarographically studied in aqueous medium. The ionic strength has been maintained constant at μ = 1.0 mol l-1 by using NaClO4. The overall stability constants, determined by using the Schaap and McMasters method, for the coordinated species [Cd(ox)(mal)]2-, [Cd(ox)(mal)2]4- and [Cd(ox)2(mal)]4- are respectively β11 = 1.3 . 104 l2 mol-2, β12 = 5.0 . 104 l3 mol-3 and β21 = 8.7 . 104 l3 mol-3. The various coordination equilibria are discussed on the basis of statistical aspects.