Chemical Studies Of Rutherfordium (Element 104) .2. Solvent Extraction Into Tributylphosphate From Hbr Solutions

The chemical properties of element 104, rutherfordium (Rf), and its group 4 homologs and other tetravalent cations were studied by solvent extraction into tributylphosphate (TBP) from various concentrations of HBr and HCl. Since bromide is a larger and softer (more polarizable) anion than chloride, the stability of Rf-bromide complexes was expected to differ from the stability of Rf-chloride complexes, and a comparison of the two systems was undertaken. Our studies showed that the extraction trend decreased in the order Zr > Hf > Rf/Ti for HBr, compared to Zr > Hf > Rf > Ti for HCl, showing that Rf and Ti did not extract as well in either system, probably because they hydrolyzed more easily than Zr and Hf.