Livermorium

Livermorium (Lv) is name of element 116. Its location in the Periodic table is predicted to be: Period 7, Group 16.

Properties

Nuclear

Four isotopes, ²⁹³Lv through ²⁹⁰Lv have been observed, and a fifth ²⁹⁴Lv may have been observed (but not confirmed). Predicted isotopes^(1),(2,),(3) span the range from neutron dripline (near ³⁹⁰Lv) down to ²⁷⁸Lv. Peak stability is expected to lie in the band ³⁰⁰Lv to ²⁹⁴Lv, at and just below the neutron shell closure at N = 184. Maximum half-lives are in the 1 to 10 second range. Livermorium is expected to exist in supernovae and neutron star mergers (kilonovae), but nowhere else outside the 20 or so laboratories scattered throughout the galaxy which are capable of synthesizing it. It should be noted that any sample of Lv large enough to see will exist only as white-hot plasma, so its physical properties are fantasies, and its chemistry is of academic importance only.

It was first detected in 2000. Since then, about 35 atoms of livermorium have been produced. While some of those nuclei were produced by decay of Og, only ²⁹⁰Lv has not been synthesized directly. There are also plans to repeat the reaction:

$\,^{48}_{20}\mathrm{Ca} + \,^{248}_{96}\mathrm{Cm} \to \,^{296}_{116}\mathrm{Lv} ^{*} \to \,^{296-n}_{116}\mathrm{Lv} + n\,^{1}_{0}\mathrm{n}$

Th at different projectile energies in order to probe the n = 2 (2n) channel leading to ²⁹⁴Lv. This heaviest isotope is valuable for studying the N = 184 shell closure. It is also predicted to have a much longer half-life than other observed Lv isotopes.

Atomic / Chemical

Since its homolog, Po, is a metal, Lv is expected to be a post-transition metal. Theoretical work done to date indicates that it generally follows Group 16 trends, but that it is not a straightforward homolog of Po. This theoretical work has not been subjected to experimental verification for the simple reason that making enough atoms to do chemistry on is impossible at this time.

History

Discovery

During mid 2000, scientists at Dubna (JINR) detected livermorium synthesized by the reaction:

$\,^{48}_{20}\mathrm{Ca} + \,^{248}_{96}\mathrm{Cm} \to \,^{296}_{116}\mathrm{Lv} ^{*} \to \,^{293}_{116}\mathrm{Lv} + 3\,^{1}_{0}\mathrm{n}$

This, of course is the 3n channel. The 4n channel, which produces 292Lv, is also active, while both the 2n channel (²⁹⁴Lv) and 5n channel (²⁹¹Lv) might have been observed (unconfirmed).

The team repeated the experiment in April–May 2005 and detected 8 atoms of livermorium. The measured decay data confirmed the assignment of the discovery isotope as ²⁹³Lv. In this run, the team also observed ²⁹²Lv in the 4n channel for the first time.

In May 2009, the Joint Working Party reported on the discovery of copernicium and acknowledged the discovery of the isotope ²⁸³Cn. This implied the de facto discovery of livermorium, as ²⁹¹Lv (see below), from the acknowledgment of the data relating to the granddaughter ²⁸³Cn, although the actual discovery experiment may be determined as that above.

In 2011, the IUPAC evaluated the Dubna team results and accepted them as a reliable identification of element 116.

Naming

Livermorium has been called "eka polonium", but not by people who realize how badly periodicity changes in Period 7. Ununhexium (Uuh) was the temporary IUPAC systematic element name. By now, nobody calls it anything but livermorium.

The name recognizes the Lawrence Livermore National Laboratory, within the city of Livermore, California, USA, which collaborated with JINR on the discovery. The city in turn is named after the American rancher Robert Livermore, a naturalized Mexican citizen of English birth, thus demonstrating the importance of Au in superheavy element research.

References

1. 1. "Decay Modes and a Limit of Existence of Nuclei"; H. Koura; 4th Int. Conf. on the Chemistry and Physics of Transactinide Elements; Sept. 2011. 2. “Systematic Study of Decay Properties of Heaviest Elements.”; Y. M. Palenzuelaa, L. F. Ruiza, A. Karpov, and W. Greiner; Bulletin of the Russian Academy of Sciences, Physics.  Vol . 76, No.11, pp 1165 – 1177; 2012 3. "Chart of the Nuclides, 2014", Japan Atomic Energy Agency; website available using "chart of nuclides" and "JAEA" as internet search terms.