Atomic Number: 115
Atomic Mass: 288 amu (atomic mass units)
Melting Point: Unknown
Boiling Point: Unknown
Number of Protons: 115
Number of Electrons: 115
Number of Neutrons: 173
Classification: Metallic Man made
Crystal Structure: Unknown
Density @ 293 K: Unknown
Ununpentium is one of the most recent of the super-heavy elements to be discovered. New elements are rare and it was a great surprise to the scientific world when on February 2 2004 it was announced that not one but two new elements had been created.
A team of Russian scientists at the Joint Institute for Nuclear Research in Dubna, Russia working with their American colleagues from the Lawrence Livermore National Laboratory conducted the successful experiment in between July 14 and August 10 2003. They used the U400 cyclotron with the Dubna gas-filled recoil separator to bombard a target of americium-243 atoms with accelerated ions of calcium-43. By observing the atomic decay patterns produced they concluded that four atoms of element 115 had been created. These atoms decayed to form the other new element ununtrium (Uut) or element 113.
Three of the four atoms produced were of the isotope ununpentium-288 which has a half life of 87 milliseconds it decays by alpha decay to form ununtrium-284. The other atom was ununpentium-287 with a half life of 32 milliseconds this also decayed by alpha decay to form ununtrium-283. The isotopes of ununtrium decayed to form isotopes of Roentgenium (element 111).
The results of their experiments have been published in a peer reviewed journal and can be found in the February 2004 edition of Physical Review under the title “Experiments on the synthesis of element 115 in the reaction 243Am(43Ca,xn)291-x115”.
The International Union for Pure and Applied Chemistry (IUPAC) awaits confirmation of these experiments. Ununpentium is the IUPAC holding name for element 115. Un-un-pent stands for 1-1-5.
With only four atoms being produced very little is known about element 115. It is a p-block element within period number 7 and group 15 of the periodic table. This group, known as the Pnictogen group, also contains the elements nitrogen, phosphorous, arsenic, antimony and bismuth. It is presumed that ununpentium would be metallic and gray or white in color. The element is radioactive.
It is highly unlikely that any significant quantity of ununpentium will ever be produced. Therefore industrial applications of element 115 are equally unlikely and ununpentium will remain an element of study within laboratories working on the super-heavy elements.