Extraction behavior of short-lived isotopes of Mo/W using α-benzoinoxime: A model system for the study of seaborgium

Abstract

The liquid-liquid extraction behavior of short-lived 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.