Article

Creating New Transuranium Elements

Conclusive Evidence Of A New Element
Properties Of The New Element
Discovery Process
Recent Discoveries of New Elements
Sources and Further Reading

Conclusive Evidence Of A New Element

To be able to add to the Periodic Table of elements is an honour that only a handful of scientists have experienced, but now a research team from Japan can join that illustrious list. Scientists at the RIKEN Nishina Center for Accelerator-based Science, located Wako, near Tokyo, have found the most conclusive evidence yet that they have created element number 113 on the periodic table.

The new element has yet to be named, but Japan will claim the naming rights if it is confirmed that they can claim the discovery. If this is the case, it will become the first element to be named by a research team in Asia. The element currently has the temporary name of Ununtrium, in accordance with the systematic naming system created by IUPAC.

Properties Of The New Element

Though there has been little chance to study Ununtrium, there are certain properties that can be determined:

Chemical symbol Uut
Atomic number 113
Relative atomic mass of 284
It will reside in Group 13, Period 7 and Block p of the periodic table
Highly radioactive, with a half-life of around 0.48s
Currently there is no known biological role for this element

The new element 133 is a ‘superheavy element’ - The superheavy elements are not known to occur naturally and are therefore termed ‘synthetic’ elements.

Another term for these elements is the ‘transuranium elements’ (or transuranics). This term applies to any elements that have an atomic number of more than 92 and hence lie past uranium in the periodic tables.

Discovery Process

The search for unambiguous data regarding the new element has been hard to come by: it has taken nine years of hard work by the research team led by Dr. Kosuke Morita.

The element was first reported in 2003 by a team led by Yuri Oganessian and Ken Moody at the Joint Institute for Nuclear Research in Dubna, Russia. The team created element 115 by the fusion of calcium-48 with americium-243 and element 113 was seen as a decay product of element 115.

It was then reported again independently in 2004, by the team at RIKEN, from the fusion of bismuth atoms (83 protons) with zinc ions (30 protons). However, according to the Royal Society of Chemistry, these results were not conclusive enough to be classified as a ‘discovery’ by the International Union of Pure and Applied Chemistry (IUPAC).

This year, the same fusion experiment resulted again in the production of ununtrium, but this time the identity of the new element was confirmed by carefully recording a consecutive chain of 6 alpha decays, ultimately finishing at mendelevium-254.

The following video showing the decay process in more detail.

Recent Discoveries of New Elements

Though ununtrium is an exciting breakthrough, evidence for synthesized elements up to number 118 in the periodic table has been found. Earlier this year, elements 114 and 116 were officially named by IUPAC. Element 114 has been dubbed flerovium (in honour of the Flerov Laboratory, Russia) and element 116 is called livermorium (in honour of Lawrence Livermore National Laboratory, USA).

Elements 115 and 117 have also been created, but as with Ununtrium, the evidence for these has not been officially reviewed yet. The next challenge for scientists is to look at elements beyond 119.

These discoveries are achieved through painstaking work by using nuclear fusion or neutron absorption and, as with the case Ununtrium, can take years to confirm.

Why is so much effort put into discovering these ‘artificial’ elements beyond uranium, apart from pure scientific curiosity? According to Professor Martyn Poliakoff (University of Nottingham), part of the reason may be that there have been predictions of ‘islands of stability’ at high atomic numbers. Although in general heavier elements have shorter half-lives, some may have a surprisingly long half-life. So scientists are working systematically through the elements to see if any of these are anomalously stable. If these islands of stability are found they could have practical scientific applications. Though none of the elements so far have the required half-life to be stable enough, they are nonetheless important scientific discoveries.