Studies of Complexes of the Transition Metals. II. Cobalt Complex with Dithioloxalate

The cobalt (II) ion and dithioloxalate ion form a complex which is stable in a water solution and highly colored. The complex was studied by means of spectrophotometric methods in the visible region. By using the method of continuous variation of Job and the method of varying mole ratio, the composition of the complex was found to be that of three moles of ligand to one mole of cobalt. The overall formation constant of the complex was determined by the method of varying mole ratio and by successive dilutions of stoichiometric proportions of ligand and metal. The ionic strength of these solutions was kept constant at 0.1, and the measurements were made at room temperature. It was assured that the cobalt (III) complex was not present in the studies by oxidizing a cobalt (II) complex and determining its spectrum. The results of this research indicate that the cobalt complex with dithioloxalate is more stable than the corresponding oxygen complex