No abstract

Experimental investigations of transactinoide elements provide benchmark results for chemical theory and probe the predictive power of trends in the periodic table. So far, in gas-phase chemical reactions, simple inorganic compounds with the transactinoide in its highest oxidation state have been synthesized. Single-atom production rates, short half-lives, and harsh experimental conditions limited the number of experimentally accessible compounds. We applied a gas-phase carbonylation technique previously tested on short-lived molybdenum (Mo) and tungsten (W) isotopes to the preparation of a carbonyl complex of seaborgium, the 106th element. The volatile seaborgium complex showed the same volatility and reactivity with a silicon dioxide surface as those of the hexacarbonyl complexes of the lighter homologs Mo and W. Comparison of the product's adsorption enthalpy with theoretical predictions and data for the lighter congeners supported a Sg(CO)6 formulation.

An isothermal vacuum chromatography setup for superheavy element chemistry studies was developed and tested online at the one-atomat-a-time level. As a model system, the adsorption behavior of thallium on quartz was chosen with respect to a future chemical characterization of its superheavy homologue, element 113 (E113, Z = 113), using the described setup. Short-lived 184 Tl (t 1/2 = 10.1(5) s) was produced in the reaction 152 Gd( 35 Cl, 3n) 184 Tl and delivered as a mass-separated ion beam to the chemistry experiment: A subsurface implantation and a subsequent fast thermal release from a metal matrix was followed by isothermal vacuum chromatography as the chemical separation stage. Single atomic species passing this chromatographic separation were finally identified by time-and energy-resolved event-by-event α-spectroscopy using a diamond-based solid-state detector. The derived adsorption enthalpy of −ΔH ads SiO 2 (Tl) = 158 ± 3 kJ•mol −1 significantly exceeds available data but correlates well with the adsorption of other elements studied on the same surface. The described technique enables chemical experiments with short-lived transactinide elements (t 1/2 < 1 s), surpassing the rapidity of today's state-of-the-art gas-phase experiments by at least 1 order of magnitude.

Formation of anionic fluoride-complexes of element 104, rutherfordium, produced in the 248 Cm( 18 O, 5n) 261 Rf reaction was studied by anion-exchange on an atom-at-a-time scale. It was found that the hexafluoro complex of Rf, [RfF 6 ] 2− , was formed in the studied fluoride ion concentrations of 0.0005-0.013 M. Formation of [RfF 6 ] 2− was significantly different from that of the homologues Zr and Hf, [ZrF 6 ] 2− and [HfF 6 ] 2− ; the evaluated formation constant of [RfF 6 ] 2− is at least one-order of magnitude smaller than those of [ZrF 6 ] 2− and [HfF 6 ] 2− .