Livermorium (116)

The essentials.

Livermorium is the synthetic superheavy element with the symbol Lv and atomic number 116. The name was adopted by IUPAC on May 30, 2012, after the Lawrence Livermore National Laboratory, in California.

It is placed as the heaviest member of group 16 (VIA) although a sufficiently stable isotope is not known at this time to allow chemical experiments to confirm its position as a heavier homologue to polonium.

It was first detected in 2000, when an isotope of livermorium, ²⁹²Lv, was identified in the reaction of ²⁴⁸Cm with ⁴⁸Ca. It is very short lived and decomposes to a known isotope of element 114, ²⁸⁸₁₁₄Fl. Since then, about 35 atoms of livermorium have been produced, either directly or as a decay product of ununoctium, belonging to the four neighboring isotopes with masses 290–293. The most stable isotope known is livermorium-293 with a half-life of ~60 milliseconds. 

Name: Livermorium Symbol: Lv Atomic number: 116 Atomic weight: [ 293 ] Standard state: presumably a solid at 298 K CAS Registry ID: 54100-71-9

Group in periodic table: 16 Group name: Chalcogen Period in periodic table: 7 Block in periodic table: p-block Color: unknown, but probably metallic and silvery white or grey in appearance Classification: Metallic

Historical information

On July 19, 2000, scientists at Dubna (JINR) detected a single decay from an atom of livermorium following the irradiation of a Cm-248 target with Ca-48 ions. The results were published in December 2000. This 10.54 MeV alpha-emitting activity was originally assigned to ²⁹²Lv due to the correlation of the daughter to previously assigned ²⁸⁸Fl. That assignment was later altered to ²⁸⁹Fl, and hence this activity was correspondingly changed to ²⁹³Lv. Two further atoms were reported by the institute during their second experiment between April–May 2001.

In the same experiment they also detected a decay chain which corresponded to the first observed decay of flerovium and assigned to ²⁸⁹Fl. This activity has not been observed again in a repeat of the same reaction. However, its detection in this series of experiments indicates the possibility of the decay of an isomer of livermorium, namely ^293bLv, or a rare decay branch of the already discovered isomer,^293aLv, in which the first alpha particle was missed. Further research is required to positively assign this activity.

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.

Results published on the 6th December 2000 concerning recent experiments at Dubna in Russia (involving workers from The Joint Institute for Nuclear Research, Dubna, Russian Federation; The Lawrence Livermore National Laboratory, California, USA; The Research Institute of Atomic Reactors, Dimitrovgrad, Russian Federation; and The State Enterprise Electrohimpribor, Lesnoy, Russian Federation) describe the decay of the isotope ²⁹²Uuh (produced in the reaction of ²⁴⁸Cm with ⁴⁸Ca) to ²⁹²Uuq.

²⁴⁸₉₆Cm + ⁴⁸₂₀Ca → ²⁹²₁₁₆Lv + 4 n

This decayed 47 milliseconds later as follows to a previously identified isotope of elements 114, flerovium, Fl.

²⁹²₁₁₆Lv → ²⁸⁸₁₁₄Fl + ⁴₂He

Physical properties

• Melting point: 637-780 K; 364-507 C; 687-944 F (extrapolated)
• Boiling point: 1035-1135 K; 762-862 C; 1403-1583 F (extrapolated)
• Density of solid: 12.9 (predicted) g cm^-3

Orbital properties

• Ground state electron configuration:  [Rn].5f¹⁴.6d¹⁰.7s².7p⁴ (a guess based upon that of polonium)
• Shell structure:  2.8.18.32.32.18.6
• Term symbol:   ³P₂ (a guess based upon guessed electronic structure)

Isolation

Results published on the 6th December 2000 concerning recent experiments at Dubna in Russia (involving workers from The Joint Institute for Nuclear Research, Dubna, Russian Federation; The Lawrence Livermore National Laboratory, California, USA; The Research Institute of Atomic Reactors, Dimitrovgrad, Russian Federation; and The State Enterprise Electrohimpribor, Lesnoy, Russian Federation) describe the decay of the isotope ²⁹²Lv (produced in the reaction of ²⁴⁸Cm with ⁴⁸Ca) to ²⁹²Fl.

²⁴⁸₉₆Cm + ⁴⁸₂₀Ca → ²⁹²₁₁₆Lv + 4 n

This decayed 47 milliseconds later as follows to a previously identified isotope of element 114, Fl.

²⁹²₁₁₆Lv → ²⁸⁸₁₁₄Fl + ⁴₂He