Ununpentium
It is placed as the heaviest member of group 15 (VA) although a sufficiently stable isotope is not known at this time that would allow chemical experiments to confirm its position as a heavier homologue to bismuth. It was first observed in 2003 and about 50 atoms of ununpentium have been synthesized to date, with about 25 direct decays of the parent element having been detected. Four consecutive isotopes are currently known, 287–290Uup, with 289Uup having the longest measured half-life of ~200 ms.
Discovery of Ununpentium
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 115, ununpentium, in Dubna, Russia in 2003. The work was a collaboration between science teams led by Yuri Oganessian and Ken Moody.
The reaction was a fusion of element 20 with element 95: calcium-48 with americium-243.
The experiment began on July 14, 2003 and ended on August 10, 2003.
Calcium ions were formed into a beam in a cyclotron (a particle accelerator) and fired at a target layer of americium deposited on titanium foil.
Four atoms of element 115 (ununpentium) may have been produced, which may have alpha decayed producing element 113 (ununtrium).
The researchers believe one atom of ununpentium-287 was made, and three atoms of ununpentium-288 were made.
The International Union of Pure and Applied Chemistry (IUPAC) reviewed the evidence for the discovery of ununpentium for several years. In 2011 they announced that there was insufficient evidence to prove that the element had been made in the cyclotron.
The IUPAC report stated, “the results are encouraging but do not meet the criteria for discovery because of the paucity of events, the lack of connections to known nuclides, and the absence of cross-bombardments.”
As a result of its position in the periodic table ununpentium is expected to be classed as one of the “other metals” and to have similar properties to the metal bismuth.
Too little of the element has been synthesized for this to be confirmed. 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:
Ununpentium is harmful due to its radioactivity.
Characteristics:
- Ununpentium is a synthetic radioactive metal and has only been produced in minute amounts.
Uses of Ununpentium
- Ununpentium is of research interest only.
