Complexes and E-pH Diagrams

A detailed treatment of all the complexes formed in the Pd-Cl system will now be made. Recall that Pd+ forms four separate complexes with Cl PdCl+, PdCl2, PdCl3, and PdCU . The pertinent complex formation reactions and corresponding AG° values (in kj/mole) along with the AG°(reaction) values (in kj) are given below  

From the AG°(reaction) values, the corresponding K (Pn) values for the reactions can be calculated as follows  

Note these K s are the formation constants for the specific complex species indicated and are re-labeled as the appropriate P values. Values of P may be calculated from AG° values, as has been done, or they may often be obtained from the chemical literature. Depending upon adjustment of the relative concentrations of the Pd+ and Cl ions, each of the four complex species above can be formed as the predominant species in solution. 

Because multiple Pd-Cl complex species can co-exist in solution, the Pd+ ion concentration in solution after the addition of a given amount of the Gl ion can be calculated using the same type of treatment employed to determine the concentration of the ion as a function of pH. The total concentration of Pd, [Pd] total, found in solution is expressed by the following equation  

By applying(combining) this equation with the four P values from above, the [Pd+ ] can be determined as a function of the [Cl ] for any [Pdjtotal using the following equation  

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