Development of a SISAK extraction system for chemical studies of element 108, hassium

Chemistry of superheavy elements

The chemistry of superheavy elements - or transactinides from their position in the Periodic Table - is summarized. After giving an overview over historical developments, nuclear aspects about synthesis of neutron-rich isotopes of these elements, produced in hot-fusion reactions, and their nuclear decay properties are briefly mentioned. Specific requirements to cope with the one-atom-at-a-time situation in automated chemical separations and recent developments in aqueous-phase and gas-phase chemistry are presented. Exciting, current developments, first applications, and future prospects of chemical separations behind physical recoil separators (“pre-separator”) are discussed in detail. The status of our current knowledge about the chemistry of rutherfordium (Rf, element 104), dubnium (Db, element 105), seaborgium (Sg, element 106), bohrium (Bh, element 107), hassium (Hs, element 108), copernicium (Cn, element 112), and element 114 is discussed from an experimental point of view. Recent results are emphasized and compared with empirical extrapolations and with fully-relativistic theoretical calculations, especially also under the aspect of the architecture of the Periodic Table.

Superheavy element studies with preseparated isotopes

In recent years, significant progress in the field of superheavy element research has been achieved thanks to a novel combination of techniques from different fields. This “physical preseparation” approach includes the coupling of an ancillary setup – typically a chemistry apparatus or a counting setup – to a physical recoil separator. This latter preseparator removes unwanted nuclear reaction products as well as the intense heavy-ion beam associated with superheavy element experiments and thus isolates the evaporation residues of the nuclear fusion reactions. These are guided to the separators's focal plane, where they are extracted and available for further transport to external setups, e.g., by a gas-jet. In this overview, the development of physical preseparation is described, and experimental results from nuclear chemistry and physics that were achieved with “preseparated” isotopes are summarized, with an emphasis on results relevant for superheavy element research. The covered topics range from chemical studies in the liquid as well as in the gas phase, the measurement of nuclear decay properties and of atomic masses. Preseparation was already shown to be a very powerful approach in these studies and promises to allow further progress in superheavy element research.