Chemical Studies Of Rutherfordium (Element 104) .3. Solvent Extraction Into Triisooctylamine From Hf Solutions

The extraction of element 104, rutherfordium (Rf), and its group 4 homologs into 0.25 M triisooctylamine (TIOA) in o,m,p-xylene from various concentrations of hydrofluoric acid was studied. This extraction system was of particular interest because all group 4 cations studied formed complexes with the same coordination number (CN) of 6. Therefore, species extracted were similar and the extractability depends on the radii of the fluoride complexes. The studies showed that the extractability for the group 4 elements in this system decreases in the order Ti > Zr approximate to Hf > Rf, in inverse order from the decrease in ionic radii Rf > Zr approximate to Hf > Ti. This order is different than the order in the hydrolysis, TBP-HCl, and TBP-HBr extraction systems where Rf, due to decreasing CN, behaves more similarly to Ti than to Zr and Hf.