Wednesday 13 March 2013

Livermorium

Livermorium 


Livermorium is the synthetic superheavy element with the symbol Lv and atomic number 116. The name was adopted by IUPAC on May 31, 2012.

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. Since then, about 35 atoms of livermorium have been produced, either directly or as a decay product of ununoctium, belonging to the four neighbouring isotopes with masses 290–293. The most stable isotope known is livermorium-293 with a half-life of ~60 ms.


Discovery of Livermorium / Ununhexium

Element 116, livermorium, was first made in Dubna, Russia in July 2000. The work was a collaboration between science teams at the Joint Institute for Nuclear Research in Dubna and the Lawrence Livermore National Laboratory in California led by Yuri Oganessian and Ken Moody.

The International Union of Pure and Applied Chemistry (IUPAC) reviewed the work over a period of years and in 2011 finally accepted the discovery of ununhexium, as it was called at the time.

The reaction was a fusion of element 20 with element 96: calcium-48 with curium-248. Calcium ions were formed into a beam in a cyclotron (a particle accelerator) and fired at a curium target.

In the first instance a single atom of livermorium-292 was detected. It existed for 46.9 ms before undergoing alpha-decay to flerovium-288.

In an experiment that lasted a year, two further atoms of livermorium-292 were made. The first existed for 125.5 ms and the second for 55.0 ms. By the end of the experiment a total of 2.3 x 1019 calcium ions had been fired at the curium target.  By 2005, 30 atoms of livermorium had been made.

As a result of its position in Group 16 of the periodic table, livermorium is expected to be classed as one of the ‘other metals’ and/or to have similar properties to the metalloid polonium. Too little of the element has been synthesized for this to be confirmed.

Ununhexium (Uuh) was element 116′s temporary name until an official name was chosen by IUPAC. IUPAC has now recommended that element 116 should be named livermorium. Although this name has not yet been given final approval, there is little doubt that this will be the name chosen.

The deputy director of Russia’s Joint Institute for Nuclear Research (JINR) initially wanted element 116′s name to be derived from Muscovy, in honor of the Moscow region. (3) Subsequently, the name livermorium was chosen to honor the work carried out by the scientists from the Lawrence Livermore National Laboratory in California in the discovery of the superheavy elements.

The joint teams at JINR in Dubna and Lawrence Livermore in California have published evidence for the synthesis of elements 113, 114, 115, 116, 117 and 118.

IUPAC has accepted the discoveries of element 114 (flerovium/ununquadium) and element 116 (livermorium/ununhexium). It has not yet considered the evidence for the discovery of element 117 (ununseptium).

IUPAC requires stronger evidence before it will confirm the synthesis of element 113 (ununtrium), element 115 (ununpentium), or element 118 (ununoctium).

Appearance and Characteristics

Harmful effects:

Livermorium is harmful due to its radioactivity.

Characteristics:

  • Livermorium / Ununhexium is a synthetic radioactive metal and has only been produced in minute amounts.

Uses of Livermorium

  • Livermorium / Ununhexium is of research interest only.