Editing Tennessine (section)

==History==
{{see also|Timeline of chemical element discoveries}}

===Pre-discovery===
In December&nbsp;2004, the [[Joint Institute for Nuclear Research]] (JINR) team in [[Dubna]], [[Moscow Oblast]], Russia, proposed a joint experiment with the [[Oak Ridge National Laboratory]] (ORNL) in [[Oak Ridge, Tennessee]], United States, to synthesize element&nbsp;117 — so called for the 117&nbsp;[[proton]]s in its [[atomic nucleus|nucleus]]. Their proposal involved [[nuclear fusion|fusing]] a [[berkelium]] (element&nbsp;97) target and a [[calcium]] (element&nbsp;20) beam, conducted via bombardment of the berkelium target with calcium nuclei:<ref name="elements">{{cite press release |last=Cabage |first=B. |date=2010 |title=International team discovers element&nbsp;117 |publisher=[[Oak Ridge National Laboratory]] |url=https://web.ornl.gov/info/ornlreview/v43_2_10/article02.shtml |url-status=dead |access-date=2017-06-26 |archive-url=https://web.archive.org/web/20150923175349/https://web.ornl.gov/info/ornlreview/v43_2_10/article02.shtml |archive-date=2015-09-23}}</ref> this would complete a set of experiments done at the JINR on the fusion of [[actinide]] targets with a calcium-48 beam, which had thus far produced the new elements [[nihonium|113]]–[[livermorium|116]] and [[oganesson|118]]. ORNL—then the world's only producer of berkelium—could not then provide the element, as they had temporarily ceased production,<ref name="elements" /> and re-initiating it would be too costly.<ref name="vanderbilt">{{cite press release |title=Vanderbilt physicist plays pivotal role in discovery of new super-heavy element |publisher=Vanderbilt University |date=April 2010 |url=https://news.vanderbilt.edu/2010/04/vanderbilt-physicist-plays-pivotal-role-in-discovery-of-new-super-heavy-element-112107/ |access-date=2016-06-12}}</ref> Plans to synthesize element&nbsp;117 were suspended in favor of the confirmation of element&nbsp;118, which had been produced earlier in 2002 by bombarding a [[californium]] target with calcium.<ref name="pp2002">{{cite journal |last1=Oganessian |first1=Yu.Ts. |last2=Utyonkov |first2=V.K. |last3=Lobanov |first3=Yu.V. |last4=Abdullin |first4=F.Sh. |last5=Polyakov |first5=A.N. |last6=Shirokovsky |first6=I.V. |last7=Tsyganov |first7=Yu.S. |last8=Mezentsev |first8=A.N. |display-authors=6 |year=2002 |title=Results from the first <sup>249</sup>Cf+<sup>48</sup>Ca experiment |journal=JINR Communication |url=https://www.jinr.ru/publish/Preprints/2002/287(D7-2002-287)e.pdf |access-date=2015-09-23}}</ref> The required berkelium-249 is a by-product in californium-252 production, and obtaining the required amount of berkelium was an even more difficult task than obtaining that of californium, as well as costly: It would cost around 3.5&nbsp;million dollars, and the parties agreed to wait for a commercial order of californium production, from which berkelium could be extracted.<ref name="vanderbilt" /><ref name="InsideScience" />

The JINR team sought to use berkelium because [[calcium-48]], the [[isotopes of calcium|isotope of calcium]] used in the beam, has 20&nbsp;protons and 28&nbsp;neutrons, making a neutron–proton ratio of 1.4; and it is the lightest stable or near-stable nucleus with such a large neutron excess. Thanks to the neutron excess, the resulting nuclei were expected to be heavier and closer to the sought-after [[island of stability]].{{efn|Although stable isotopes of the lightest elements usually have a neutron–proton ratio close or equal to one (for example, the only stable isotope of [[aluminium]] has 13&nbsp;protons and 14&nbsp;neutrons,{{NUBASE2020|ref}} making a neutron–proton ratio of 1.077), stable isotopes of heavier elements have higher neutron–proton ratios, increasing with the number of protons. For example, [[iodine]]'s only stable isotope has 53&nbsp;protons and 74&nbsp;neutrons, giving neutron–proton ratio of 1.396, [[gold]]'s only stable isotope has 79&nbsp;protons and 118 neutrons, yielding a neutron–proton ratio of 1.494, and [[plutonium]]'s most stable isotope has 94&nbsp;protons and 150&nbsp;neutrons, and a neutron–proton ratio of 1.596.{{NUBASE2020|ref}} This trend<ref>{{cite book |last1=Karpov |first1=A. V. |last2=Zagrebaev |first2=V. I. |last3=Palenzuela |first3=Y. Martinez |last4=Greiner |first4=Walter |year=2013 |chapter=Superheavy Nuclei: Decay and Stability |title=Exciting Interdisciplinary Physics |page=69 |series=FIAS Interdisciplinary Science Series |doi=10.1007/978-3-319-00047-3_6 |isbn=978-3-319-00046-6}}</ref> is expected to make it difficult to synthesize the most stable isotopes of super-heavy elements as the neutron–proton ratios of the elements they are synthesized from will be too low.}} Of the aimed for 117&nbsp;protons, calcium has 20, and thus they needed to use berkelium, which has 97&nbsp;protons in its nucleus.{{NUBASE2020|ref}}

In February&nbsp;2005, the leader of the JINR team — [[Yuri Oganessian]] — presented a colloquium at ORNL. Also in attendance were representatives of Lawrence Livermore National Laboratory, who had previously worked with JINR on the discovery of elements 113–116 and 118, and [[Joseph H. Hamilton|Joseph Hamilton]] of [[Vanderbilt University]], a collaborator of Oganessian.<ref name="Oganessian" />

Hamilton checked if the ORNL high-flux reactor produced californium for a commercial order: The required berkelium could be obtained as a by-product. He learned that it did not and there was no expectation for such an order in the immediate future. Hamilton kept monitoring the situation, making the checks once in a while. (Later, Oganessian referred to Hamilton as "the father of 117" for doing this work.)<ref name="Oganessian">{{cite news |title=What it takes to make a new element |magazine=Chemistry World |url=https://www.chemistryworld.com/what-it-takes-to-make-a-new-element/1017677.article |access-date=2016-12-03}}</ref>

===Discovery===
ORNL resumed californium production in spring&nbsp;2008. Hamilton noted the restart during the summer and made a deal on subsequent extraction of berkelium<ref>{{cite web |last=Witze |first=Alexandra |year=2010 |title=The backstory behind a new element |website=Science News |url=https://www.sciencenews.org/blog/deleted-scenes/backstory-behind-new-element |access-date=2016-06-12}}</ref> (the price was about $600,000).<ref name="Bloomberg">{{Cite news|last=Subramanian|first=S.|author-link=Samanth Subramanian|url=https://www.bloomberg.com/news/features/2019-08-28/making-new-elements-doesn-t-pay-just-ask-this-berkeley-scientist|title=Making New Elements Doesn't Pay. Just Ask This Berkeley Scientist|website=[[Bloomberg Businessweek]]| date=28 August 2019 |access-date=2024-03-08}}</ref> During a September&nbsp;2008 symposium at [[Vanderbilt University]] in [[Nashville, Tennessee|Nashville]], Tennessee, celebrating his 50th year on the Physics faculty, Hamilton introduced Oganessian to James Roberto (then the deputy director for science and technology at ORNL).<ref name="symposiumintro">{{cite news |first=Emily |last=Siner |year=2016 |title=How scientists plan to enshrine Tennessee on the periodic table of elements |publisher=National Public Radio |url=https://nashvillepublicradio.org/post/how-scientists-plan-enshrine-tennessee-periodic-table-elements |access-date=2017-03-07}}</ref> They established a collaboration among JINR, ORNL, and Vanderbilt.<ref name="InsideScience" /> [[Clarice Phelps]] was part of ORNL's team that collaborated with JINR;<ref name="Phelps">{{Cite web|url=https://iupac.org/100/chemist/clarice-phelps-es/|title=Clarice Phelps|website=IUPAC 100}}</ref> this is particularly notable as because of it the IUPAC recognizes her as the first [[African-American]] woman to be involved with the discovery of a chemical element.<ref name="Phelps"/><ref>{{Cite web|url=https://iupac.org/100/pt-of-chemist/|title=PT of Younger Chemists|website=IUPAC 100}}</ref><ref>{{cite web | url=https://www.oakridger.com/news/20190729/two-ornl-researchers-featured-on-periodic-table-of-younger-chemists | archive-url=https://web.archive.org/web/20190729202324/https://www.oakridger.com/news/20190729/two-ornl-researchers-featured-on-periodic-table-of-younger-chemists | archive-date=29 July 2019 | title=Two ORNL researchers featured on 'Periodic Table of Younger Chemists' - News - Oakridger - Oak Ridge, TN - Oak Ridge, TN | work=Oakridger - Oak Ridge, TN }}</ref><ref>{{cite journal |last1=Jarvis |first1=Claire |date=2019 |title=The overlooked element makers |url=https://pubs.aip.org/physicstoday/online/31578 |journal=Physics Today |issue=9 |page=31578 |bibcode=2019PhT..2019i1578J |doi=10.1063/PT.6.4.20190930a}}</ref> The eventual collaborating institutions also included  [[The University of Tennessee, Knoxville|The University of Tennessee (Knoxville)]], [[Lawrence Livermore National Laboratory]], [[Research Institute of Atomic Reactors|The Research Institute for Advanced Reactors (Russia)]], and [[University of Nevada, Las Vegas|The University of Nevada (Las Vegas)]].<ref name="TS_Program">{{cite web| title=The Discovery of Tennessine|website=Oak Ridge National Laboratory | url=https://www.ornl.gov/sites/default/files/Ts_Program%20Final%20sm.pdf |access-date=2023-06-11}}</ref> 

[[File:Berkelium.jpg|thumb|left|The berkelium target used for the synthesis (in solution)|alt=A very small sample of a blue liquid in a plastic pipette held by a hand wearing heavy protection equipment]]

In November 2008, the [[United States Department of Energy|U.S. Department of Energy]], which had oversight over the [[High Flux Isotope Reactor|reactor in Oak Ridge]], allowed the scientific use of the extracted berkelium.<ref name="discoveryornl">{{cite press release |first=James |last=Roberto |year=2010 |publisher=Oak Ridge National Laboratory |title=The discovery of element&nbsp;117 |url=https://www.fornl.info/Presentations/Discovery%20of%20Element%20117%20final.pdf |access-date=2017-06-26 |url-status=dead |archive-url=https://web.archive.org/web/20161021230058/https://www.fornl.info/Presentations/Discovery%20of%20Element%20117%20final.pdf |archive-date=2016-10-21}}</ref>

The production lasted 250&nbsp;days and ended in late December&nbsp;2008,<ref name="forthepress" /> resulting in 22&nbsp;milligrams of berkelium, enough to perform the experiment.<ref name="eurekalert" /> In January 2009, the berkelium was removed from ORNL's High Flux Isotope Reactor;<ref name="discoveryornl" /> it was subsequently cooled for 90 days and then processed at ORNL's Radiochemical Engineering and Development Center to separate and purify the berkelium material, which took another 90 days.<ref name="InsideScience" /> Its [[half-life]] is only 330&nbsp;days: this means, after that time, half the berkelium produced would have [[radioactive decay|decayed]]. Because of this, the berkelium target had to be quickly transported to Russia; for the experiment to be viable, it had to be completed within six months of its departure from the United States.<ref name="InsideScience">{{cite web |title=An Atom at the End of the Material World |year=2010 |first=J. S. |last=Bardi |url=https://www.insidescience.org/content/atom-end-material-world/1042 |publisher=Inside Science |access-date=2015-01-03|archiveurl=https://web.archive.org/web/20231202174353/http://www.insidescience.org/content/atom-end-material-world/1042|archivedate=December 2, 2023}}</ref> The target was packed into five lead containers to be flown from New York to Moscow.<ref name="InsideScience" />
Russian customs officials twice refused to let the target enter the country because of missing or incomplete paperwork. Over the span of a few days, the target traveled over the Atlantic Ocean five times.<ref name="InsideScience" /> On its arrival in Russia in June 2009, the berkelium was immediately transferred to [[Research Institute of Atomic Reactors]] (RIAR) in [[Dimitrovgrad (Russia)|Dimitrovgrad]], [[Ulyanovsk Oblast]], where it was deposited as a 300-[[nanometer]]-thin layer on a [[titanium]] film.<ref name="forthepress">{{cite press release |publisher=[[Joint Institute for Nuclear Research]] |title=For the Press |year=2010 |url=https://flerovlab.jinr.ru/linkc/117/For%20press%20Z=117.doc |access-date=2015-07-28 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304120450/https://flerovlab.jinr.ru/linkc/117/For%20press%20Z=117.doc |url-status=dead }}</ref> In July&nbsp;2009, it was transported to Dubna,<ref name="forthepress" /> where it was installed in the [[particle accelerator]] at the JINR.<ref name="eurekalert">{{cite press release |last=Stark |first=A.M. |year=2010 |title=International team discovers element&nbsp;117 |publisher=[[United States Department of Energy|DOE]] / [[Lawrence Livermore National Laboratory]] |url=https://www.eurekalert.org/pub_releases/2010-04/dlnl-itd040610.php |archive-url=https://web.archive.org/web/20100407155147/http://www.eurekalert.org/pub_releases/2010-04/dlnl-itd040610.php |url-status=dead |archive-date=7 April 2010 |access-date=2012-11-29 }}</ref> The [[calcium-48]] beam was generated by [[extraction (chemistry)|chemically extracting]] the small quantities of calcium-48 present in naturally occurring calcium, enriching it 500 times.<ref name="discoveryornl" /> This work was done in the [[Closed city|closed town]] of [[Lesnoy, Sverdlovsk Oblast]], Russia.<ref name="discoveryornl" />

The experiment began in late July&nbsp;2009.<ref name="discoveryornl" /> In January 2010, scientists at the [[Flerov Laboratory of Nuclear Reactions]] announced internally that they had detected the [[Radioactive decay|decay]] of a new element with atomic number&nbsp;117 via two decay chains: one of an [[odd-odd nuclei|odd–odd]] isotope undergoing 6&nbsp;[[alpha decay]]s before [[spontaneous fission]], and one of an [[odd-even nuclei|odd–even]] isotope undergoing 3 alpha decays before fission.<ref name="E117">{{cite conference |url=https://www.jinr.ru/img_sections/PAC/NP/31/PAK_NP_31_recom_eng.pdf |title=Recommendations|conference=31st meeting, PAC for nuclear physics |last=Greiner |first=W. |page=6 |date=2010 |url-status=dead |archive-url=https://web.archive.org/web/20100414173735/https://www.jinr.ru/img_sections/PAC/NP/31/PAK_NP_31_recom_eng.pdf |archive-date=2010-04-14}}</ref> The obtained data from the experiment was sent to the LLNL for further analysis.<ref>{{cite press release |title=Nations work together to discover new element |year=2011 |publisher=U.S. [[Department of Energy]] |department=DOE Office of Science |website=[[U.S. Department of Energy]] |url=https://science.energy.gov/news/featured-articles/2011/127004/ |access-date=2016-01-05}}</ref> On 9&nbsp;April 2010, an official report was released in the journal ''[[Physical Review Letters]]'' identifying the isotopes as <sup>294</sup>117 and <sup>293</sup>117, which were shown to have half-lives on the [[order of magnitude|order]] of tens or hundreds of [[millisecond]]s. The work was signed by all parties involved in the experiment to some extent: JINR, ORNL, LLNL, RIAR, Vanderbilt, the [[University of Tennessee]] ([[Knoxville, Tennessee]], U.S.), and the [[University of Nevada, Las Vegas|University of Nevada]] ([[Las Vegas, Nevada]], U.S.), which provided data analysis support.<ref name="vanderbilt.edu">{{cite web |title=Heaviest in the world |date=November 2011 |website=Arts and Science Magazine |publisher=Vanderbilt University |url=https://www.vanderbilt.edu/magazines/arts-and-science/2010-11/heaviest-in-the-world/ |access-date=2016-06-12 |url-status=dead |archive-url=https://web.archive.org/web/20160503072001/https://www.vanderbilt.edu/magazines/arts-and-science/2010-11/heaviest-in-the-world/ |archive-date=2016-05-03}}</ref> The isotopes were formed as follows:<ref name="117s" />{{efn|A nuclide is commonly denoted by the chemical element's symbol immediately preceded by the mass number as a superscript and the atomic number as a subscript. Neutrons are represented as nuclides with atomic mass&nbsp;1, atomic number&nbsp;0, and symbol '''n'''. Outside the context of nuclear equations, the atomic number is sometimes omitted. An asterisk denotes an extremely short-lived (or even non-existent) intermediate stage of the reaction.}}

:{{nuclide|Berkelium|249}} + {{nuclide|calcium|48}} → <sup>297</sup>117* → <sup>294</sup>117 + 3 {{su|b=0|p=1}}{{SubatomicParticle|neutron}} (1 event)

:{{nuclide|Berkelium|249}} + {{nuclide|calcium|48}} → <sup>297</sup>117* → <sup>293</sup>117 + 4 {{su|b=0|p=1}}{{SubatomicParticle|neutron}} (5 events)

=== 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>

=== Naming ===
[[File:CorneliusVanderbiltStatue.JPG|thumb|left|Main campus of Hamilton's workplace, Vanderbilt University, one of the institutions named as co-discoverers of tennessine]]
Using [[Mendeleev's predicted elements|Mendeleev's nomenclature for unnamed and undiscovered elements]], element&nbsp;117 should be known as ''eka-[[astatine]]''. Using the 1979 [[systematic element name|recommendations]] by the [[International Union of Pure and Applied Chemistry]] (IUPAC), the element was [[placeholder name|temporarily called]] ''ununseptium'' (symbol ''Uus''), formed from [[Latin language|Latin]] roots "one", "one", and "seven", a reference to the element's atomic number&nbsp;117.<ref name="iupac">{{cite journal |last=Chatt |first=J. |date=1979 |title=Recommendations for the naming of elements of atomic numbers greater than 100 |journal=Pure Appl. Chem. |volume=51 |issue=2 |pages=381–384 |doi=10.1351/pac197951020381|doi-access=free }}</ref> Many scientists in the field called it "element&nbsp;117", with the symbol ''E117'', ''(117)'', or ''117''.<ref name="Haire" /> According to guidelines of IUPAC valid at the moment of the discovery approval, the permanent names of new elements should have ended in "-ium"; this included element&nbsp;117, even if the element was a [[halogen]], which traditionally have names ending in "-ine";<ref>{{cite journal |last=Koppenol |first=W.H. |year=2002 |title=Naming of new elements |series=IUPAC Recommendations 2002 |journal=Pure and Applied Chemistry |volume=74 |issue=5 |pages=787–791 |s2cid=95859397 |doi=10.1351/pac200274050787 |url=https://media.iupac.org/publications/pac/2002/pdf/7405x0787.pdf}}</ref> however, the new recommendations published in 2016 recommended using the "-ine" ending for all new group&nbsp;17 elements.<ref>{{cite journal |last1=Koppenol |first1=Willem H. |last2=Corish |first2=John |last3=García-Martínez |first3=Javier |last4=Meija |first4=Juris |last5=Reedijk |first5=Jan |year=2016 |title=How to name new chemical elements |series=IUPAC Recommendations 2016 |journal=Pure and Applied Chemistry |volume=88 |issue=4 |pages=401–405 |doi=10.1515/pac-2015-0802 |hdl=10045/55935 |s2cid=102245448 |url=https://rua.ua.es/dspace/bitstream/10045/55935/1/2016_Koppenol_etal_PureApplChem.pdf|hdl-access=free }}</ref>

After the original synthesis in 2010, [[Dawn Shaughnessy]] of LLNL and Oganessian declared that naming was a sensitive question, and it was avoided as far as possible.<ref>{{cite press release |last=Glanz |first=J. |year=2010 |title=Scientists discover heavy new element |publisher=[[Oregon State University]] |department=Department of Chemistry |url=https://chemistry.oregonstate.edu/courses/ch121-3/ch123/ch123latestnews/ch123ln.htm |access-date=2016-01-05 |archive-date=18 April 2017 |archive-url=https://web.archive.org/web/20170418135305/http://chemistry.oregonstate.edu/courses/ch121-3/ch123/ch123latestnews/ch123ln.htm |url-status=dead }}</ref> However, Hamilton, who teaches at [[Vanderbilt University]] in [[Nashville, Tennessee]], declared that year, "I was crucial in getting the group together and in getting the <sup>249</sup>Bk target essential for the discovery. As a result of that, I'm going to get to name the element. I can't tell you the name, but it will bring distinction to the region."<ref name="vanderbilt.edu" /> In a 2015 interview, Oganessian, after telling the story of the experiment, said, "and the Americans named this a tour de force, they had demonstrated they could do [this] with no margin for error. Well, soon they will name the 117th element."<ref name="OTR">{{cite interview |last=Oganessian |first=Yu.Ts. |title=Гамбургский счет |url=https://www.youtube.com/watch?v=ZdnvOxxDeKM | archive-url=https://ghostarchive.org/varchive/youtube/20211111/ZdnvOxxDeKM| archive-date=2021-11-11 | url-status=live|access-date=2020-01-18 |date=2015-10-10 |interviewer-last=Orlova |interviewer-first=O. |trans-title=Hamburg reckoning |language=ru |publisher=[[Public Television of Russia]]}}{{cbignore}}</ref>

In March&nbsp;2016, the discovery team agreed on a conference call involving representatives from the parties involved on the name "tennessine" for element&nbsp;117.<ref name="Oganessian" /> In June 2016, IUPAC published a declaration stating the discoverers had submitted their suggestions for naming the new elements&nbsp;115, 117, and 118 to the IUPAC; the suggestion for the element&nbsp;117 was ''tennessine'', with a symbol of ''Ts'', after "the region of Tennessee".{{efn|name=fn1}} The suggested names were recommended for acceptance by the IUPAC Inorganic Chemistry Division; formal acceptance was set to occur after a five-month term following publishing of the declaration expires.<ref name="IUPAC-June2016">{{cite press release | url = https://iupac.org/iupac-is-naming-the-four-new-elements-nihonium-moscovium-tennessine-and-oganesson/ | title = IUPAC Is Naming The Four New Elements Nihonium, Moscovium, Tennessine, and Oganesson | date = 2016-06-08 | publisher = IUPAC | access-date = 2016-06-08}}</ref> In November 2016, the names, including tennessine, were formally accepted. Concerns that the proposed symbol ''Ts'' may clash with a notation for the [[tosyl]] group used in organic chemistry were rejected, following existing symbols bearing such dual meanings: Ac ([[actinium]] and [[Acetyl group|acetyl]]) and Pr ([[praseodymium]] and [[Propyl group|propyl]]).<ref>{{Cite news |url=https://iupac.org/iupac-announces-the-names-of-the-elements-113-115-117-and-118/ |title=IUPAC Announces the Names of the Elements&nbsp;113, 115, 117, and 118 |date=2016-11-30 |newspaper=IUPAC |language=en-US |access-date=2016-11-30}}</ref> The naming ceremony for [[moscovium]], tennessine, and [[oganesson]] was held on 2 March 2017 at the [[Russian Academy of Sciences]] in [[Moscow]]; a separate ceremony for tennessine alone had been held at ORNL in January<!--the 27th--> 2017.<ref>{{cite web |url=https://www.jinr.ru/posts/at-the-inauguration-ceremony-of-the-new-elements-of-the-periodic-table-of-d-i-mendeleev/ |title=At the inauguration ceremony of the new elements of the periodic table of D.I. Mendeleev |last=Fedorova |first=Vera |date=3 March 2017|publisher=[[Joint Institute for Nuclear Research]] |access-date=4 February 2018}}</ref>