FIRST AQUEOUS CHEMISTRY WITH SEABORGIUM (ELEMENT-106)

For the first time, chemical separations of element 106 (Seaborgium, S g) were performed in aqueous solutions. The isotopes (265)Sg and (266) Sg were produced in the Cm-248 + Ne-22 reaction at a beam energy of 12 1 MeV. The reaction products were continuously transported by a He(KCl )-jet to the computer-controlled liquid chromatography system ARCA. In 0.1 M HNO3/5 x 10(-4) M HF Sg was found to be eluted within 10 s from 1.6 x 8 mm cation-exchange columns (Aminex A6, 17.5 +/- 2 mu m) toget her with the hexavalent Mo- and W-ions, while hexavalent U-ions and te travalent Zr-, Hf-, and element 104 ions were strongly retained on the column. Element 106 was detected by measuring correlated a-decays of the daughter isotopes 78-s (261)104 and 26-s (257)102. For the isotope (266)Sg, We have evidence for a spontaneous fission branch. It yields a partial spontaneous-fission half-life which is in agreement with re cent theoretical predictions. The chemical results show that the most stable oxidation state of Sg in aqueous solution is +6, and that like its homologs Mo and W, Sg forms neutral or anionic ore-or oxohalide-co mpounds under the present condition. In these first experiments, Sg ex hibits properties very characteristic of group 6 elements, and does no t show U-like properties.