Theoretical Predictions of Complex Formation of Group-4 Elements Zr, Hf, and Rf in H2SO4 Solutions

Complex formation of Zr, Hf, and Rf in HF and HCl solutions has been studied both experimentally and theoretically [1,2]. Trends in Kd (distribution coefficient) values evidencing the strengths of formed complexes were shown to be influenced by such factors as pH of solution and acid concentration. Presently, experiments are under way to investigate complex formation of these elements in H2SO4 solutions using the SISAK technique [3]. To predict the outcome of these experiments, the present theoretical study has been undertaken. Accordingly, calculations of the free energy change, G, of the following complex formation reactions were performed: