Element 117 Of The Periodic Table Is Named Ununseptium And Now Confirmed

Confirmed and published! Ununseptium is the name of Element 117 of the periodic table. It was originally discovered back in 2010 by a group of American and Russian physicists with the Joint Institute for Nuclear Research (JINR). After so many years, the study has been replicated by another independent team, which the International Union of Pure and Applied Chemistry (IUPAC).

The new element, with the approval of the IUPAC, can be named and added to the periodic table, extending our understanding of transuranium elements.

Here is the synopsis of the paper published in Physical Review Letters:

Nuclear physicists have invested huge effort in creating superheavy elements, which consist of enough neutrons to provide enhanced stability from nuclear decay. For the past 30 years, experiments have been marching towards this “island of stability” with a new elemental discovery every 2 to 3 years. Part of the discovery process includes the confirmation by an independent experimental collaboration—it is only at this point that an element obtains its official status.

An international team using an intense Ca beam provided by GSI research facility in Darmstadt, Germany, and a target material of radioactive Bk supplied by Oak Ridge National Lab in Tennessee has produced two atoms of the superheavy element with atomic number Z=117, confirming the initial observation published in 2010. In the process, a new isotope Lr was discovered from the previously unknown alpha-decay branch of Db. With a half-life of 1 hour, Db is the longest-lived alpha emitter having an atomic number, Z, greater than 102.

The experiment is a tour de force in superheavy element research and required a detailed reconstruction of a seven-step alpha-decay chain followed by the spontaneous fission of the newly discovered Lr. The difficulty stems from the large variation in decay lifetimes along the alpha chain. The discovery was made feasible by the use of TASCA, a gas-filled recoil separator specifically designed for a high selectivity of superheavy or transactinide elements.

The confirmation by the TASCA team serves as a much-needed step on the long road towards the island of stability. An easier feat will be deciding on a name for Z=117.