Ununseptium Element Facts

Discovery of Ununseptium

In 2009, the first atoms of element 117 were made in the Flerov Laboratory of Nuclear Reactions in Dubna, Russia. Evidence of the synthesis was published in April 2010, by scientific teams from Russia and the United States of America. ^{(1), (2)}

The research effort, led by Yuri Oganessian, was a collaboration between the Joint Institute of Nuclear Research (Dubna, Russia); the Research Institute for Advanced Reactors, Dimitrovgrad; Lawrence Livermore National Laboratory; Oak Ridge National Laboratory; Vanderbilt University, Tennessee; and the University of Nevada, Las Vegas.

The discovery has not yet been verified by IUPAC. Ununseptium’s place in the periodic table is unofficial until IUPAC validates its existence.

Ununseptium was made by a fusion reaction of element 20 with element 97: calcium-48 with berkelium-249.

Calcium ions were formed into a beam in a cyclotron (a particle accelerator) and fired at a target layer of berkelium deposited 300 nm thick on titanium foil.

The first bombardment lasted 70 days. The berkelium was bombarded with over 7 trillion calcium-48 ions per second, accelerated to about 10% of the speed of light.

The data suggest five nuclei of interest were produced during the 70 day bombardment. As a consequence of the high energy of the impacts that created them, these nuclei instantly lost thermal energy by emitting four neutrons to form ununseptium-293.

The ununseptium-293 (approximate half-life 14 ms) decayed by alpha emission into element 115 (ununpentium). ^{(2), (3)}

In a second bombardment lasting 50 days, the speed of the bombarding calcium-48 ions was reduced. The resulting impacts were of lower energy and the single nucleus of interest that formed needed to emit just three neutrons to lose its excess energy, leading to the heavier ununseptium-294 isotope. The data suggest one atom of ununseptium-294 (approximate half-life 78 ms) was formed in the bombardment, decaying again to element 115.

As a result of its position in Group 17 of the periodic table, ununseptium is expected to have chemical properties characteristic of the halogens. The effects of relativistic electrons, however, may result in partial metalloid properties.