Studies of fundamental properties of rutherfordium (Element 104) using organic complexing agents

Abstract

Chemical properties of rutherfordium (Rf) have been investigated with the organic ligands triisooctylamine (TIOA), tributylphosphate (TBP), and thenoyltrifluoroacetone (TTA). The TIOA studies showed that Rf behaves differently than Th and Eu and most similarly to Zr, only Zr and Rf extract from 12 M HCI. This result is further evidence that Rf is a Group 4 element. Studies with TBP showed that Rf chemical behavior differed from the other Group 4 elements. The extractior_ by TBP at different chloride concentrations showed that Rf at times behaves more like Pu 4+ than Zr or Hf. At high chloride concentrations, Rf and Pu extraction decreased. Under the same conditions, Zt', Hf and Th extraction increased, in addition, Rf extraction by TBP was affected by hydrogen ion concentration, while Zr and Hf extraction was not. TTA ..×tractions were used to determine the Keq, Khyd, and the ionic radius of Rf. .P.' The log Keq for Rf with 'TTA was calculated to be 3.18 i 0.90. The first four log Khyd'S for Rf are calculated to be-2.6 _:0.7,-5.9 ± 1.7,-10.2 :_2.9, and-14.5 _: 4.1. These hydrolysis constants indicate that Rf will not hydrolyze at conditions under which Zr, Hf, and Pu will. Calculations of the ionic radius were made with the log Keq for Rf derived with TTA. The ionic radius of Rf was calculated to be " 91 ± 4 pm for the 6-coordinate species and 102 ± 4 pm for the 8-coordinate species. A search for the isotope 263Rf was conducted using TTA chemistry. In 300 experiments, seven SF events and no alpha events were observed in the Rf chemical fraction. The observed SF events were attributed to 263Rf and had + 300 a half-life of 500-200 seconds and a production cross section of 140-+ 50 pb.