View source for Tennessine

=== Confirmation ===
[[File:DecayChain Tennessine.svg|thumb|upright=1.5|Decay chain of the atoms produced in the original experiment. The figures near the arrows describe experimental (black) and theoretical (blue) values for the lifetime and [[decay energy|energy]] of each decay. Lifetimes may be converted to [[half-life|half-lives]] by multiplying by [[Natural logarithm of 2|ln&nbsp;2]].<ref name="117s" />]]
All [[daughter isotope]]s (decay products) of element&nbsp;117 were previously unknown;<ref name="117s">{{cite journal|last1=Oganessian |first1=Yu.Ts. |author-link1=Yuri Oganessian |last2=Abdullin |first2=F.Sh. |last3=Bailey |first3=P.D. |last4=Benker |first4=D.E. |last5=Bennett |first5=M.E. |last6=Dmitriev |first6=S.N. |last7=Ezold |first7=J.G. |last8=Hamilton |first8=J.H. |last9=Henderson |first9=R.A. |first10=M.G. |last10=Itkis |first11=Yuri V. |last11=Lobanov |first12=A.N. |last12=Mezentsev |first13=K. J. |last13=Moody |first14=S.L. |last14=Nelson |first15=A.N. |last15=Polyakov | first16=C.E. |last16=Porter |first17=A.V. |last17=Ramayya |first18=F.D. |last18=Riley |first19=J.B. |last19=Roberto |first20=M. A. |last20=Ryabinin | first21=K.P. |last21=Rykaczewski |first22=R.N. |last22=Sagaidak | first23=D.A. |last23=Shaughnessy |first24=I.V. |last24=Shirokovsky |first25=M.A. |last25=Stoyer |first26=V.G. |last26=Subbotin | first27=R. |last27=Sudowe |first28=A.M. |last28=Sukhov |first29=Yu.S. |last29=Tsyganov |first30=Vladimir K. |last30=Utyonkov |first31=A.A. |last31=Voinov |first32=G.K. |last32=Vostokin | first33=P.A. |last33=Wilk |display-authors=6 |title=Synthesis of a new element with atomic number {{nowrap|{{mvar|Z}} {{=}} 117}} |year=2010 |journal=Physical Review Letters |volume=104 |issue=14 |page=142502 |doi=10.1103/PhysRevLett.104.142502 |pmid=20481935 |bibcode=2010PhRvL.104n2502O |s2cid=3263480 |doi-access=free }}</ref> therefore, their properties could not be used to confirm the claim of discovery. In 2011, when one of the decay products ({{sup|289}}115) was synthesized directly, its properties matched those measured in the claimed indirect synthesis from the decay of element&nbsp;117.<ref>{{cite web |last=Molchanov |first=E. |year=2011 |script-title=ru:В лабораториях ОИЯИ. Возвращение к дубнию |trans-title=In JINR labs. Returning to dubnium |publisher=JINR |url=https://www.jinr.ru/news_article.asp?n_id=954&language=rus |access-date=2011-11-09 |language=ru}}</ref> The discoverers did not submit a claim for their findings in 2007–2011 when the [[IUPAC/IUPAP Joint Working Party|Joint Working Party]] was reviewing claims of discoveries of new elements.<ref>{{cite journal |last1=Barber |first1=R.C. |last2=Karol |first2=P.J. |last3=Nakahara |first3=H. |last4=Vardaci |first4=E. |last5=Vogt |first5=E.W. |year=2011 |title=Discovery of the elements with atomic numbers greater than or equal to 113 |series=IUPAC Technical Report |journal=Pure and Applied Chemistry |volume=83 |issue=7 |pages=1485–1498 |s2cid=98065999 |doi=10.1351/PAC-REP-10-05-01|url=https://zenodo.org/record/6472770 |doi-access=free }}</ref>

The Dubna team repeated the experiment in 2012, creating seven atoms of element&nbsp;117 and confirming their earlier synthesis of element&nbsp;118 (produced after some time when a significant quantity of the [[berkelium]]-249 target had [[beta decay]]ed to [[californium]]-249). The results of the experiment matched the previous outcome;<ref name="277Mt" /> the scientists then filed an application to register the element.{{citation needed|date=November 2020}} In May&nbsp;2014, a joint German–American collaboration of scientists from the ORNL and the [[GSI Helmholtz Center for Heavy Ion Research]] in [[Darmstadt]], [[Hessen]], Germany, claimed to have confirmed discovery of the element.<ref name="266Lr" /><ref>{{cite web |first=D. |last=Chow |date=2014-05-01 |title=New super-heavy element&nbsp;117 confirmed by scientists |publisher=Live Science |url=https://www.livescience.com/45289-superheavy-element-117-confirmed.html |access-date=2014-05-02}}</ref> The team repeated the Dubna experiment using the Darmstadt accelerator, creating two atoms of element&nbsp;117.<ref name="266Lr" />

In December&nbsp;2015, the JWP officially recognized the discovery of <sup>293</sup>117 on account of the confirmation of the properties of its daughter {{sup|289}}115,<ref>{{cite press release |title=Discovery and assignment of elements with atomic numbers&nbsp;113, 115, 117 and 118 |publisher=IUPAC |year=2015 |url=https://www.iupac.org/news/news-detail/article/discovery-and-assignment-of-elements-with-atomic-numbers-113-115-117-and-118.html |access-date=2016-01-04 |archive-date=7 February 2016 |archive-url=https://web.archive.org/web/20160207061337/http://www.iupac.org/news/news-detail/article/discovery-and-assignment-of-elements-with-atomic-numbers-113-115-117-and-118.html |url-status=dead }}</ref> and thus the listed discoverers — JINR, LLNL, and ORNL — were given the right to suggest an official name for the element. (Vanderbilt was left off the initial list of discoverers in an error that was later corrected.)<ref>{{cite journal |last1=Karol |first1=Paul J. |last2=Barber |first2=Robert C. |last3=Sherrill |first3=Bradley M. |last4=Vardaci |first4=Emanuele |last5=Yamazaki |first5=Toshimitsu |date=22 December 2015 |title=Discovery of the elements with atomic numbers {{nowrap|{{mvar|Z}} {{=}} 113,}} 115, and 117 |series=IUPAC Technical Report |journal=Pure Appl. Chem. |volume=88 |issue=1–2 |pages=139–153 |doi=10.1515/pac-2015-0502 |s2cid=101634372 |url=https://www.degruyter.com/downloadpdf/j/pac.2016.88.issue-1-2/pac-2015-0502/pac-2015-0502.pdf |access-date=2 April 2016}}</ref>

In May&nbsp;2016, [[Lund University]] ([[Lund]], [[Scania]], Sweden) and GSI cast some doubt on the syntheses of elements&nbsp;[[Moscovium|115]] and 117. The decay chains assigned to {{sup|289}}115, the isotope instrumental in the confirmation of the syntheses of elements&nbsp;115 and 117, were found based on a new statistical method to be too different to belong to the same nuclide with a reasonably high probability. The reported <sup>293</sup>117 decay chains approved as such by the JWP were found to require splitting into individual data sets assigned to different isotopes of element&nbsp;117. It was also found that the claimed link between the decay chains reported as from {{sup|293}}117 and {{sup|289}}115 probably did not exist. (On the other hand, the chains from the non-approved isotope {{sup|294}}117 were found to be [[wikt:congruent|congruent]].) The multiplicity of states found when nuclides that are not even–even undergo alpha decay is not unexpected and contributes to the lack of clarity in the cross-reactions. This study criticized the JWP report for overlooking subtleties associated with this issue, and considered it "problematic" that the only argument for the acceptance of the discoveries of elements&nbsp;115 and 117 was a link they considered to be doubtful.<ref>{{cite journal |last1=Forsberg |first1=U. |last2=Rudolph |first2=D. |first3=C. |last3=Fahlander |first4=P. |last4=Golubev |first5=L.G. |last5=Sarmiento |first6=S. |last6=Åberg |first7=M. |last7=Block |first8=Ch.E. |last8=Düllmann |first9=F.P. |last9=Heßberger |first10=J.V. |last10=Kratz |first11=A. |last11=Yakushev |date=9 July 2016 |title=A new assessment of the alleged link between element&nbsp;115 and element 117 decay chains |journal=Physics Letters&nbsp;B |volume=760 |issue=2016 |pages=293–296 |doi=10.1016/j.physletb.2016.07.008 |bibcode=2016PhLB..760..293F |url=https://portal.research.lu.se/portal/files/9762047/PhysLettB760_293_2016.pdf |access-date=2 April 2016|doi-access=free }}</ref><ref>{{cite conference |last1=Forsberg |first1=Ulrika |last2=Fahlander |first2=Claes |last3=Rudolph |first3=Dirk |year=2016 |title=Congruence of decay chains of elements&nbsp;113, 115, and 117  |conference=Nobel Symposium NS160 – Chemistry and Physics of Heavy and Superheavy Elements |doi=10.1051/epjconf/201613102003 |url=https://www.epj-conferences.org/articles/epjconf/pdf/2016/26/epjconf-NS160-02003.pdf|doi-access=free }}</ref>

On 8&nbsp;June 2017, two members of the Dubna team published a journal article answering these criticisms, analysing their data on the nuclides {{sup|293}}117 and {{sup|289}}115 with widely accepted statistical methods, noted that the 2016 studies indicating non-congruence produced problematic results when applied to radioactive decay: they excluded from the 90% confidence interval both average and extreme decay times, and the decay chains that would be excluded from the 90% confidence interval they chose were more probable to be observed than those that would be included. The 2017 reanalysis concluded that the observed decay chains of {{sup|293}}117 and {{sup|289}}115 were consistent with the assumption that only one nuclide was present at each step of the chain, although it would be desirable to be able to directly measure the mass number of the originating nucleus of each chain as well as the excitation function of the {{nowrap|[[Americium|{{sup|243}}Am]] + [[Calcium-48|{{sup|48}}Ca]]}} reaction.<ref>{{cite journal |last1=Zlokazov |first1=V.B. |last2=Utyonkov |first2=V.K. |date=8 June 2017 |title=Analysis of decay chains of superheavy nuclei produced in the {{nowrap|{{sup|249}}Bk + {{sup|48}}Ca}} and {{nowrap|{{sup|243}}Am + {{sup|48}}Ca}} reactions |journal=Journal of Physics&nbsp;G: Nuclear and Particle Physics |volume=44 |issue=7 |page=075107 |doi=10.1088/1361-6471/aa7293 |doi-access=free |bibcode=2017JPhG...44g5107Z}}</ref>