Gas chemical properties of heaviest elements

Abstract

Summary. Chemical studies at the upper end of the periodic table have reached atomic number 114. Recent experiments aiming at investigating chemical properties of elements Cn, 113, and 114 are summarized. Though partly preliminary, all these elements behave as expected: due to the filled 6d 10 shell, they do not behave like transition metals anymore, as observed for the lighter transactinides. They exhibit a volatile behavior as expected for 7s and 7 p elements. On the other hand, due to the extremely low signal to noise ratio in detectors used to identify separated products highest precaution on identifying single atoms is mandatory. As an example, published early attempts to synthesize Cn and to perform chemical studies with this element that could not be confirmed in later studies are summarized.

Chemistry of superheavy elements

“…However, even with a sensitivity limit of 2.5 pb reached, 283 Cn was not unambiguously detected [248]. Also, a follow-up experiment made at Dubna was not able to observe 283 Cn [40]; see [249] for a critical discussion of these experiments.…”

“…Hot-fusion reactions are characterized by excitation energies of 35 MeV to 55 MeV when nuclei from 238 U to 249 Cf fuse with beams from 18 O to 48 Ca. Consequently, three to five neutrons are emitted before the compound nucleus has cooled.…”

“…11. Schematic view of the IVO-COLD device used in Cn and element 114 experiments at the FLNR in Dubna [41,149,249]. A highly purified He/Ar gas-mixture, circulating in a closed loop, transports products to a cooled array of 32 detector pairs (COLD); photo of one detector pair is shown.…”

“…A highly purified He/Ar gas-mixture, circulating in a closed loop, transports products to a cooled array of 32 detector pairs (COLD); photo of one detector pair is shown. Figure adapted from [249]. Courtesy of R. Eichler.…”

“…It was at the Flerov Laboratory of Nuclear Reactions (FLNR) in Dubna where, over the last decade, Oganessian and coworkers carried out large series of experiments irradiating targets ranging from 238 U to 249 Cf with 48 Ca beams. Products were separated with the Dubna Gas-Filled Recoil Separator (DGFRS).…”