Discovery of the elements with atomic numbers greater than or equal to 113 (IUPAC Technical Report)

Abstract

Abstract:The IUPAC/IUPAP Joint Working Party (JWP) on the priority of claims to the discovery of new elements 113-116 and 118 has reviewed the relevant literature pertaining to several claims. In accordance with the criteria for the discovery of elements previously established by the 1992 IUPAC/IUPAP Transfermium Working Group (TWG), and reinforced in subsequent IUPAC/IUPAP JWP discussions, it was determined that the Dubna-Livermore collaborations share in the fulfillment of those criteria both for elements Z = 114 and 116. A synopsis of experiments and related efforts is presented.

Discovery of the elements with atomic numbers Z = 113, 115 and 117 (IUPAC Technical Report)

“…The new elements identified in the claims considered here have distinct features from their assigned Z = 114 and Z = 116 neighbors [5]. The nature of the alpha energy spectra observed in the decays of nuclides with atomic numbers 113, 115, and 117 differ from their even-Z neighbors and show a wider energy spread corresponding to decay to excited states.…”

“…These Criteria have served effectively as guiding principles by subsequent JWPs [2][3][4][5]. Those references should be consulted by interested parties as the Criteria serve to provide a uniform, consistent basis for definitive observation and interpretation that is generally agreed to by investigators.…”

“…Each concise profile begins with a reprise of the pertinent content from earlier reports [1][2][3][4][5] if any. An historical account of the relevant publications on each element is given appended with the JWP's consensus opinion(s) as to the value of the evidence on the basis of the Criteria.…”

Chemistry of superheavy elements

“…Recently, Dubna-Livermore collaborations were credited with the discovery of element 114 and 116 [251] and, in the presently ongoing process, the proposed names and symbols flerovium, Fl, and livermorium, Lv, respectively, were provisionally recommended [252].…”

First online multireflection time-of-flight mass measurements of isobar chains produced by fusion-evaporation reactions: Toward identification of superheavy elements via mass spectroscopy

“…Time-of-flight spectra for three isobar chains, 204 In the search for the long-predicted "island of stability" [1], the use of so-called hot-fusion reactions has allowed for extending the observed periodic table of elements up to element 118 in recent years. However, a dearth of projectiletarget combinations available for cross-bombardment reactions along with α-decay chains terminating in spontaneous fission before reaching well-known nuclei bottlenecked the International Union of Pure and Applied Chemistry's acceptance of elements 113, 115, 117, and 118 [2] until very recently. As we push ever closer to the island of stability, whether by use of more exotic projectile-target combinations or use of multinucleon transfer reactions [3], this problem will become ever more severe; we can expect many spontaneously fissioning nuclei, longer α-decay half-lives, and a recurrence of β-decay [4].…”