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Physical Chemistry

Element 117 Repeat

Superheavy element is now eligible to become the new end of the periodic table, if the findings are judged to be conclusive

by Jyllian Kemsley
May 12, 2014 | A version of this story appeared in Volume 92, Issue 19

Four years after scientists first reported the creation of element 117, researchers working at a second facility have observed it as well (Phys. Rev. Lett. 2014, DOI: 10.1103/physrevlett.112.172501). The additional finding should strengthen the case for adding element 117 to the periodic table, where it would take its place as the heaviest element confirmed to exist, even if it does so only briefly. Element 117 was first sighted in 2010 in experiments done at Russia’s Joint Institute for Nuclear Research, where researchers smashed a stream of 48Ca atoms into a 249Bk target. The scientists tracked two isotopes, 293117 and 294117, through their nuclear decay chains. Similar experiments in Russia turned up element 117 again in 2012. In the new work, scientists led by Jadambaa Khuyagbaatar at Germany’s GSI heavy-ion accelerator center also combined 48Ca and 249Bk and saw evidence of two atoms of 294117. In the past two years, researchers have repeated sightings of elements 113 and 115 as well. If an international committee deems all the claims conclusive, row seven of the periodic table will be only one element short of completion.


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