Ununoctium
The radioactive ununoctium atom is very unstable, and since 2002, only three or possibly four atoms of the isotope 294Uuo have been detected. While this allowed for very little experimental characterization of its properties and possible compounds, theoretical calculations have resulted in many predictions, including some unexpected ones. For example, although ununoctium is a member of Group 18, it may possibly not be a noble gas, unlike all the other Group 18 elements. It was formerly thought to be a gas but is now predicted to be a solid under normal conditions due to relativistic effects.
Discovery of Ununoctium
Research scientists at the Joint Institute for Nuclear Research in Dubna, Russia and the Lawrence Livermore National Laboratory (LLNL), California believed they had made element 118, ununoctium, in 2002.
The reaction was a fusion of element 20 with element 98: calcium-48 with californium-249.
Calcium ions were formed into a beam in a cyclotron (a particle accelerator) and fired at a target layer of californium oxide deposited on titanium foil.
Bombardment lasted 2300 hours, accumulating a total dose of 2.5 x 1019 calcium ions.
Two atoms of ununoctium-294, which existed for 2.55 ms and 3.16 ms, may have been produced in March 2002.
In 2011, The International Union of Pure and Applied Chemistry (IUPAC) reviewed the work done in Dubna and at the LLNL, and did not accept that there was enough evidence to accept ununoctium as an established element.
The report stated, “the three events reported for the Z = 118 isotope have very good internal redundancy but with no anchor to known nuclei do not satisfy the criteria for discovery.”
As a result of its position in the periodic table ununoctium is expected to be classed as a noble gas.
Too little of the element has been synthesized for this to be confirmed, although some calculations indicate ununoctium might in fact be solid at room temperature.
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 (ununquadium) and element 116 (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:
Ununoctium is harmful due to its radioactivity.
Characteristics:
- Ununoctium is a synthetic radioactive metal and has only been produced in minute amounts.
Uses of Ununoctium
- Ununoctium is of research interest only.
