Chemical Properties of Element 105 in Aqueous Solution: Halide Complex Formation and Anion Exchange into Triisoctyl Amine

Abstract

Studies of the halide complexation of element 105 in aqueous solution were performed on 34-s ²⁶²Ha produced in the ²⁴⁹Bk(^lsO,5n) reaction. The ²⁶²Ha was detected by measuring the fission and alpha activities associated with its decay and the alpha decays of its daughter, 4.3-s ²⁵⁸Lr. Time-correlated pairs of parent and daughter alpha particles provided a unique identification of the presence of ²⁶²Ha. About 1600 anion exchange separations of ²⁶²Ha from HCl and mixed HC1/HF solutions were performed on a one-minute time scale. Reversed-phase micro-chromatographic columns incorporating triisooctyl amine (TIOA) on an inert support were used in the computer-controlled liquid chromatography apparatus, ARCA II. ²⁶²Ha was shown to be adsorbed on the column from either 12 M HC1/0.02 M HF or 10 M HC1 solutions like its homologs Nb and Ta, and like Pa. In elutions with 4 M HC1/0.02 M HF (Pa-Nb fraction), and with 6 M HN0₃/0.015 M HF (Ta fraction), the ²⁶²Ha activity was found in the Pa-Nb fraction showing that the anionic halide complexes are different from those of Ta, and are more like those of Nb and Pa. In separate elutions with 10 M HC1/0.025 M HF (Pa fraction) and 6 M HN0₃/0.015 M HF (stripping of Nb) the ²⁶²Ha was found to be equally divided between the Pa and Nb fractions. The non-tantalum like halide complexation of Ha is indicative of the formation of oxohalide or hydroxohalide complexes, like [NbOCI₄]^-and [PaOCl₄]^-or [Pa(OH)₂Cl₄]^-, at least for intermediate HC1 concentrations, in contrast to the pure halide complexes in Ta, like [TaCl₆]^-.