Short-lived isotopes / Technetium trioxide / Isothermal gas chromatography / Adsorption enthalpySummary. In order to study the gas-phase chemical behavior of transactinides, an on-line isothermal chromatography apparatus has been developed and applied to separate shortlived technetium isotopes in the form of TcO 3 from fission products. The fission products from a 252 Cf source were continuously and rapidly transported through the capillary to the isothermal chromatography apparatus using the N 2 /KBr gas-jet techniques. Volatile oxide molecules were formed at the reaction zone kept at 900 • C since a trace amount of oxygen existed in the N 2 carrier gas. With the new developed isothermal chromatography apparatus, a selective separation of Tc from fission products was achieved. After isothermal chromatographic separation, 101,103,104,105,106,107,108 Tc were dominantly observed together with their Ru daughters in the γ -spectrum, The chemical yields of 101 Tc, 104 Tc and 105 Tc isotopes with longer half-lives are about 55-57%, and those of 103 Tc, 106 Tc, 107 Tc and 108 Tc isotopes with shorter half-lives dropped down to 25-28%. The adsorption enthalpy of the investigated compounds on quartz surfaces was determined to be −150 ± 5 kJ/mol by fitting the measured retention curves with a Monte Carlo model. The observed species of technetium oxide is attributed to TcO 3 , which is in good agreement with previous experimental results. That means our system worked properly and it can be used to investigate the gas-phase chemical behavior of transactinides.

No abstract

Liquid-liquid extraction / α-benzoinoxime / Molybdenum / Tungsten / SeaborgiumSummary. The liquid-liquid extraction behavior of shortlived molybdenum and tungsten isotopes from HCl and HNO 3 as well as HF/HNO 3 acid media was studied using the α-benzoinoxime/chloroform system. The goal of the present experiments was to find an extraction system with a high selectivity for the group 6 elements in the periodic table which is suitable for the study the solution chemistry of seaborgium (Z = 106). It was found that Mo and W are both effectively extracted using α-benzoinoxime as an extractant and the maximum extraction yield is 100% and 94% for Mo and W, respectively. Ions of MO 2 2+ (M = Mo, W) exist in HCl between the concentration range of 0.1-3 M and can be extracted quantitatively into the organic phase. The decrease of extraction yields at lower or higher acid concentration is due to the formation of anionic species MO 4 2− or MO 2 Cl 3 − . The extraction behavior of Mo and W in HNO 3 solution is similar to that in HCl solution. In HNO 3 /HF mixed acid solutions, due to the formation of MO 2 F 3 − a decrease of extraction yield at higher HF concentration, similar to the case of HCl is observed. The extraction equilibrium is reached within 10-30 s, which means the extraction kinetics of α-benzoinoxime/chloroform extraction system is fast enough for the study of the isotope 265 Sg. The extraction behavior of molybdenum and tungsten shows a distinct difference in the range of 0.05 to 0.2 M HF with 1 M HNO 3 . This shows that differences in the complexation with fluoride ion exist in Mo and W. This study focuses on the investigation of the tendency of group 6 element for complexation with fluoride ion.

No abstract