View source for Chemistry:Tennessine

{{Infobox tennessine}}

'''Tennessine''' is a [[Physics:Synthetic element|synthetic chemical element]]; it has [[Chemistry:Chemical symbol|symbol]] '''Ts''' and [[Physics:Atomic number|atomic number]] 117. It is the second-heaviest known element and the penultimate element of the [[Chemistry:Period 7 element|7th period]] of the [[Chemistry:Periodic table|periodic table]].

The discovery of tennessine was officially announced in [[Organization:Dubna|Dubna]], Russia, by a Russian–American collaboration in April 2010, which makes it the most recently discovered element {{As of|2024|lc=y}}. One of its [[Physics:Decay product|daughter isotopes]] was created directly in 2011, partially confirming the results of the experiment. The experiment itself was repeated successfully by the same collaboration in 2012 and by a joint German–American team in May 2014. In December 2015, the Joint Working Party of the [[Organization:International Union of Pure and Applied Chemistry|International Union of Pure and Applied Chemistry]] (IUPAC) and the [[Organization:International Union of Pure and Applied Physics|International Union of Pure and Applied Physics]] (IUPAP), which evaluates claims of discovery of new elements, recognized the element and assigned the priority to the Russian–American team. In June 2016, the IUPAC published a declaration stating that the discoverers had suggested the name ''tennessine'' after {{wipe|Tennessee}}, United States, a name which was officially adopted in November 2016.<!-- not "November 28": Keep date formatting throughout the article consistent (currently "month year"; there's no real need for the exact dates) -->{{efn|The declaration by the IUPAC mentioned "the contribution of the Tennessee ''region'' (emphasis added), including [[Organization:Oak Ridge National Laboratory|Oak Ridge National Laboratory]], [[Organization:Vanderbilt University|Vanderbilt University]], and the [[Organization:University of Tennessee|University of Tennessee]] at Knoxville, Tennessee, to superheavy element research, including the production and chemical separation of unique actinide target materials for superheavy element synthesis at ORNL’s [[Physics:High Flux Isotope Reactor|High Flux Isotope Reactor]] (HFIR) and Radiochemical Engineering Development Center (REDC)".|name=fn1}}

Tennessine may be located in the "[[Physics:Island of stability|island of stability]]", a concept that explains why some superheavy elements are more stable compared to an overall trend of decreasing stability for elements beyond [[Chemistry:Bismuth|bismuth]] on the periodic table. The synthesized tennessine atoms have lasted tens and hundreds of [[Millisecond|millisecond]]s. In the periodic table, tennessine is expected to be a member of group 17, the [[Chemistry:Halogen|halogen]]s.{{efn|The term "[[Chemistry:Group (periodic table)|group]] 17" refers to a column in the periodic table starting with [[Chemistry:Fluorine|fluorine]]. The term "halogen" is sometimes considered as synonymous, but sometimes it instead relates to a common set of chemical and physical properties shared by fluorine, [[Chemistry:Chlorine|chlorine]], [[Chemistry:Bromine|bromine]], [[Chemistry:Iodine|iodine]], and [[Chemistry:Astatine|astatine]], all of which precede tennessine in group 17. Unlike the other group 17 members, tennessine ''might not'' be a halogen under this stricter definition.<ref name="notgonnabeahalogen" />}} Some of its properties may differ significantly from those of the lighter halogens due to [[Chemistry:Relativistic quantum chemistry|relativistic effects]]. As a result, tennessine is expected to be a volatile [[Chemistry:Metal|metal]] that neither forms anions nor achieves high [[Chemistry:Oxidation state|oxidation state]]s. A few key properties, such as its melting and boiling points and its first [[Physics:Ionization energy|ionization energy]], are nevertheless expected to follow the [[Chemistry:Periodic trends|periodic trends]] of the halogens.

==Introduction==
{{Excerpt|Superheavy element|Introduction|subsections=yes}}

==History==

===Pre-discovery===
In December&nbsp;2004, the [[Organization:Joint Institute for Nuclear Research|Joint Institute for Nuclear Research]] (JINR) team in [[Organization:Dubna|Dubna]], Moscow Oblast, Russia, proposed a joint experiment with the [[Organization:Oak Ridge National Laboratory|Oak Ridge National Laboratory]] (ORNL) in Oak Ridge, {{wipe|Tennessee}}, United States, to synthesize element&nbsp;117 — so called for the 117&nbsp;[[Physics:Proton|proton]]s in its [[Physics:Atomic nucleus|nucleus]]. Their proposal involved [[Physics:Nuclear fusion|fusing]] a [[Chemistry:Berkelium|berkelium]] (element&nbsp;97) target and a [[Chemistry:Calcium|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=[[Organization:Oak Ridge National Laboratory|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 [[Chemistry:Actinide|actinide]] targets with a calcium-48 beam, which had thus far produced the new elements [[Chemistry:Nihonium|113]]–[[Chemistry:Livermorium|116]] and [[Chemistry:Oganesson|118]]. The 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 [[Chemistry:Californium|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 [[Physics:Calcium-48|calcium-48]], the [[Physics: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 [[Physics:Island of stability|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 [[Chemistry:Aluminium|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, [[Chemistry:Iodine|iodine]]'s only stable isotope has 53&nbsp;protons and 74&nbsp;neutrons, giving neutron–proton ratio of 1.396, [[Chemistry:Gold|gold]]'s only stable isotope has 79&nbsp;protons and 118 neutrons, yielding a neutron–proton ratio of 1.494, and [[Chemistry:Plutonium|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 — [[Biography:Yuri Oganessian|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 Hamilton of [[Organization:Vanderbilt University|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" /> During a September&nbsp;2008 symposium at [[Organization:Vanderbilt University|Vanderbilt University]] in 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" /> [[Biography:Clarice Phelps|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>https://web.archive.org/web/20190729202324/https://www.oakridger.com/news/20190729/two-ornl-researchers-featured-on-periodic-table-of-younger-chemists</ref><ref>https://pubs.aip.org/physicstoday/online/31578</ref> The eventual collaborating institutions also included  The University of Tennessee (Knoxville), [[Organization:Lawrence Livermore National Laboratory|Lawrence Livermore National Laboratory]], The Research Institute for Advanced Reactors (Russia), and [[Organization: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 U.S. Department of Energy, which had oversight over the [[Physics: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 [[Physics:Half-life|half-life]] is only 330&nbsp;days: this means, after that time, half the berkelium produced would have [[Physics: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 }}</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, Ulyanovsk Oblast, where it was deposited as a 300-nanometer-thin layer on a [[Chemistry:Titanium|titanium]] film.<ref name="forthepress">{{cite press release |publisher=[[Organization:Joint Institute for Nuclear Research|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 [[Physics:Particle accelerator|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=DOE / [[Organization:Lawrence Livermore National Laboratory|Lawrence Livermore National Laboratory]] |url=https://www.eurekalert.org/pub_releases/2010-04/dlnl-itd040610.php |access-date=2012-11-29 }}</ref> The [[Physics:Calcium-48|calcium-48]] beam was generated by [[Chemistry:Extraction|chemically extracting]] the small quantities of calcium-48 present in naturally occurring calcium, enriching it 500 times.{{citation needed|date=November 2020}} This work was done in the 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 [[Physics:Radioactive decay|decay]] of a new element with atomic number&nbsp;117 via two decay chains: one of an odd–odd isotope undergoing 6&nbsp;[[Physics:Alpha decay|alpha decay]]s before [[Physics:Spontaneous fission|spontaneous fission]], and one of an 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 ''[[Physics:Physical Review Letters|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|millisecond]]s. The work was signed by all parties involved in the experiment to some extent: JINR, ORNL, LLNL, RIAR, Vanderbilt, the [[Organization:University of Tennessee|University of Tennessee]] (Knoxville, {{wipe|Tennessee}}, U.S.), and the [[Organization: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 [[Physics:Decay energy|energy]] of each decay. Lifetimes may be converted to half-lives by multiplying by [[Natural logarithm of 2|ln&nbsp;2]].<ref name="117s" />]]
All daughter isotopes (decay products) of element&nbsp;117 were previously unknown;<ref name="117s">{{cite journal|last1=Oganessian |first1=Yu.Ts. |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 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 [[Chemistry:Berkelium|berkelium]]-249 target had [[Physics:Beta decay|beta decay]]ed to [[Chemistry:Californium|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, [[Organization:Lund University|Lund University]] (Lund, Scania, Sweden) and GSI cast some doubt on the syntheses of elements&nbsp;[[Chemistry: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 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|[[Chemistry:Americium|{{sup|243}}Am]] + [[Physics: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 [[Chemistry:Mendeleev's predicted elements|Mendeleev's nomenclature for unnamed and undiscovered elements]], element&nbsp;117 should be known as ''eka-[[Chemistry:Astatine|astatine]]''. Using the 1979 [[Chemistry:Systematic element name|recommendations]] by the [[Organization:International Union of Pure and Applied Chemistry|International Union of Pure and Applied Chemistry]] (IUPAC), the element was temporarily called ''ununseptium'' (symbol ''Uus'') until its discovery was confirmed and a permanent name chosen; the temporary name was formed from [[Social: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 [[Chemistry:Halogen|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=[[Organization:Oregon State University|Oregon State University]] |department=Department of Chemistry |url=https://chemistry.oregonstate.edu/courses/ch121-3/ch123/ch123latestnews/ch123ln.htm |access-date=2016-01-05}}</ref> However, Hamilton 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" /> (Hamilton teaches at [[Organization:Vanderbilt University|Vanderbilt University]] in Nashville, Tennessee, U.S.) 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 [[Chemistry:Tosyl|tosyl]] group used in organic chemistry were rejected, following existing symbols bearing such dual meanings: Ac ([[Chemistry:Actinium|actinium]] and [[Chemistry:Acetyl group|acetyl]]) and Pr ([[Chemistry:Praseodymium|praseodymium]] and [[Chemistry: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 - IUPAC {{!}} International Union of Pure and Applied Chemistry |date=2016-11-30 |newspaper=IUPAC {{!}} International Union of Pure and Applied Chemistry |language=en-US |access-date=2016-11-30}}</ref> The naming ceremony for [[Chemistry:Moscovium|moscovium]], tennessine, and [[Chemistry:Oganesson|oganesson]] was held on 2 March 2017 at the Russian Academy of Sciences in [[Place:Moscow|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 |website=jinr.ru |publisher=[[Organization:Joint Institute for Nuclear Research|Joint Institute for Nuclear Research]] |access-date=4 February 2018}}</ref>

== Predicted properties ==
Other than nuclear properties, no properties of tennessine or its compounds have been measured; this is due to its extremely limited and expensive production<ref name="Bloomberg" /> and the fact that it decays very quickly. Properties of tennessine remain unknown and only predictions are available.

=== Nuclear stability and isotopes ===
{{main|Physics:Isotopes of tennessine}}

The stability of nuclei quickly decreases with the increase in atomic number after [[Chemistry:Curium|curium]], element&nbsp;96, whose half-life is four orders of magnitude longer than that of any subsequent element. All isotopes with an atomic number above [[Chemistry:Mendelevium|101]] undergo radioactive decay with half-lives of less than 30 hours. No elements with atomic numbers above 82 (after [[Chemistry:Lead|lead]]) have stable isotopes.<ref>{{cite journal |last1=de Marcillac |first1=P. |last2=Coron |first2=N. |last3=Dambier |first3=G. |last4=Leblanc |first4=J. |last5=Moalic |first5=J.-P. |display-authors=3 |date=2003 |title=Experimental detection of α-particles from the radioactive decay of natural bismuth |journal=Nature |volume=422 |pages=876–878 |pmid=12712201 |doi=10.1038/nature01541 |issue=6934 |bibcode=2003Natur.422..876D |s2cid=4415582 }}</ref> This is because of the ever-increasing Coulomb repulsion of protons, so that the [[Physics:Strong nuclear force|strong nuclear force]] cannot hold the nucleus together against [[Physics:Spontaneous fission|spontaneous fission]] for long. Calculations suggest that in the absence of other stabilizing factors, elements with more than [[Chemistry:Rutherfordium|104 protons]] should not exist.<ref name="liquiddrop">{{cite journal |last=Möller |first=P. |date=2016 |title=The limits of the nuclear chart set by fission and alpha decay |journal=EPJ Web of Conferences |volume=131 |pages=03002:1–8 |url=https://inspirehep.net/record/1502715/files/epjconf-NS160-03002.pdf |doi=10.1051/epjconf/201613103002 |bibcode=2016EPJWC.13103002M|doi-access=free }}</ref> However, researchers in the 1960s suggested that the closed [[Physics:Nuclear shell model|nuclear shells]] around 114&nbsp;protons and 184&nbsp;neutrons should counteract this instability, creating an "[[Physics:Island of stability|island of stability]]" where nuclides could have half-lives reaching thousands or millions of years. While scientists have still not reached the island, the mere existence of the [[Physics:Superheavy element|superheavy element]]s (including tennessine) confirms that this stabilizing effect is real, and in general the known superheavy nuclides become exponentially longer-lived as they approach the predicted location of the island.<ref>{{cite book |title=Van&nbsp;Nostrand's scientific encyclopedia |first1=G.D. |last1=Considine |first2=Peter H. |last2=Kulik |publisher=Wiley-Interscience |date=2002 |edition=9th |isbn=978-0-471-33230-5 |oclc=223349096 }}</ref><ref name="retro">{{cite journal |last1=Oganessian |first1=Yu. Ts. |last2=Sobiczewski |first2=A. |last3=Ter-Akopian |first3=G. M. |date=9 January 2017 |title=Superheavy nuclei: from predictions to discovery |journal=Physica Scripta |volume=92 |issue=2 |pages=023003–1–21 |doi=10.1088/1402-4896/aa53c1 |bibcode=2017PhyS...92b3003O |s2cid=125713877 }}</ref> Tennessine is the second-heaviest element created so far, and all its known isotopes have half-lives of less than one second. Nevertheless, this is longer than the values predicted prior to their discovery: the predicted lifetimes for <sup>293</sup>Ts and <sup>294</sup>Ts used in the discovery paper were 10&nbsp;ms and 45&nbsp;ms respectively, while the observed lifetimes were 21&nbsp;ms and 112&nbsp;ms respectively.<ref name="117s" /> The Dubna team believes that the synthesis of the element is direct experimental proof of the existence of the island of stability.<ref name="IS" />

[[File:Island of Stability derived from Zagrebaev.svg|center|thumb|upright=3.0|alt=A 2D graph with rectangular cells colored in black-and-white colors, spanning from the llc to the urc, with cells mostly becoming lighter closer to the latter|A chart of nuclide stability as used by the Dubna team in 2010. Characterized isotopes are shown with borders. According to the discoverers, the synthesis of element 117 serves as definite proof of the existence of the "island of stability" (circled).<ref name="IS">{{cite web |title=Element 117 is synthesized |url=https://www.jinr.ru/news_article.asp?n_id=539& |date=2010 |publisher=JINR |access-date=2015-06-28 }}</ref>]]

It has been calculated that the isotope <sup>295</sup>Ts would have a half-life of about 18&nbsp;[[Millisecond|millisecond]]s, and it may be possible to produce this isotope via the same berkelium–calcium reaction used in the discoveries of the known isotopes, <sup>293</sup>Ts and <sup>294</sup>Ts. The chance of this reaction producing <sup>295</sup>Ts is estimated to be, at most, one-seventh the chance of producing <sup>294</sup>Ts.{{sfn|Zagrebaev|Karpov|Greiner|2013|page=3}}<ref name="FengE117">{{cite journal |arxiv=0708.0159 |doi=10.1088/0256-307X/24/9/024 |title=Possible Way to Synthesize Superheavy Element ''Z'' = 117 |date=2007 |last1=Zhao-Qing |first1=F. |journal=Chinese Physics Letters |volume=24 |page=2551 |last2=Gen-Ming |first2=Jin |last3=Ming-Hui |first3=Huang |last4=Zai-Guo |first4=Gan |last5=Nan |first5=Wang |last6=Jun-Qing |first6=Li |issue=9 |bibcode = 2007ChPhL..24.2551F |s2cid=8778306 |display-authors=3 }}</ref><ref name="FengHotFusion">{{cite journal |arxiv=0803.1117 |doi=10.1016/j.nuclphysa.2008.11.003 |title=Production of heavy and superheavy nuclei in massive fusion reactions |date=2009 |first1=F. |last1=Zhao-Qing |journal=Nuclear Physics A |volume=816 |issue=1–4 |page=33 |last2=Jina |first2=Gen-Ming |last3=Li |first3= Jun-Qing |last4=Scheid |first4=Werner |display-authors=3 |bibcode=2009NuPhA.816...33F |s2cid=18647291 }}</ref> Calculations using a quantum tunneling model predict the existence of several isotopes of tennessine up to <sup>303</sup>Ts. The most stable of these is expected to be <sup>296</sup>Ts with an alpha-decay half-life of 40&nbsp;milliseconds.<ref name="prc08ADNDT08">{{cite journal |journal=Physical Review C |volume=77 |page=044603 |date=2008 |title=Search for long lived heaviest nuclei beyond the valley of stability |first1=R. P. |last1=Chowdhury |first2=C. |last2=Samanta |first3=D. N. |last3=Basu |doi=10.1103/PhysRevC.77.044603 |bibcode=2008PhRvC..77d4603C |issue=4 |arxiv=0802.3837 |s2cid=119207807 }}</ref> A [[Physics:Semi-empirical mass formula#The liquid drop model and its analysis|liquid drop model]] study on the element's isotopes shows similar results; it suggests a general trend of increasing stability for isotopes heavier than <sup>301</sup>Ts, with partial half-lives exceeding the [[Astronomy:Age of the universe|age of the universe]] for the heaviest isotopes like <sup>335</sup>Ts when beta decay is not considered.<ref name="Brazil">{{cite journal |last1=Duarte |first1=S. B. |last2=Tavares |first2=O. A. P. |last3=Gonçalves |first3=M. |last4=Rodríguez |first4=O. |last5=Gúzman |first5=F. |last6=Barbosa |first6=T. N. |last7=García |first7=F. |last8=Dimarco |first8=A. |display-authors=3 |title=Half-life prediction for decay modes for superheavy nuclei |journal=Journal of Physics G: Nuclear and Particle Physics |series=Notas de Física |number=CBPF-NF-022/04 |publisher=Centro Brasileiro de Pesquisas Físicas |date=September 2004 |volume=30 |pages=1487–1494 |issn=0029-3865 |url=https://www.iaea.org/inis/collection/NCLCollectionStore/_Public/36/073/36073846.pdf |doi=10.1088/0954-3899/30/10/014|bibcode=2004JPhG...30.1487D }}</ref> Lighter isotopes of tennessine may be produced in the <sup>243</sup>Am+<sup>50</sup>Ti reaction, which was considered as a contingency plan by the Dubna team in 2008 if <sup>249</sup>Bk proved unavailable.<ref>{{cite web |url=https://nuclphys.sinp.msu.ru/nseminar/12.02.08.pdf |title=Синтез новых элементов 113-118 в реакциях полного слияния <sup>48</sup>Ca + <sup>238</sup>U-<sup>249</sup>Cf |trans-title=Synthesis of new elements 113–118 in complete fusion reactions <sup>48</sup>Ca + <sup>238</sup>U–<sup>249</sup>Cf |last=Utyonkov |first=V. K. |date=12 February 2008 |website=nuclphys.sinp.msu.ru |access-date=28 April 2017}}</ref>
{{Clear}}

===Atomic and physical===
Tennessine is expected to be a member of group 17 in the periodic table, below the five halogens; [[Chemistry:Fluorine|fluorine]], [[Chemistry:Chlorine|chlorine]], [[Chemistry:Bromine|bromine]], [[Chemistry:Iodine|iodine]], and [[Chemistry:Astatine|astatine]], each of which has seven valence electrons with a configuration of {{Nowrap|''n''s<sup>2</sup>''n''p<sup>5</sup>}}.<ref>{{Cite book |title = The Sterling Dictionary Of Chemistry |url = https://books.google.com/books?id=SvSmSYC6lW0C |publisher = Sterling Publishers Pvt. Ltd|date = 1999-12-01 |isbn = 978-81-7359-123-5 |first = A. |last = Dhingra |page = 187 |access-date = 2015-07-23}}</ref>{{efn|The letter ''n'' stands for the number of the period (horizontal row in the periodic table) the element belongs to. The letters "s" and "p" denote the ''s'' and ''p'' [[Physics:Atomic orbital|atomic orbital]]s, and the subsequent superscript numbers denote the numbers of electrons in each. Hence the notation {{Nowrap|''n''s<sup>2</sup>''n''p<sup>5</sup>}} means that the valence shells of lighter group 17&nbsp;elements are composed of two ''s'' electrons and five ''p'' electrons, all located in the outermost electron energy level.}} For tennessine, being in the seventh period (row) of the periodic table, continuing the trend would predict a valence electron configuration of {{Nowrap|7s<sup>2</sup>7p<sup>5</sup>}},<ref name="Haire" /> and it would therefore be expected to behave similarly to the halogens in many respects that relate to this electronic state. However, going down group&nbsp;17, the metallicity of the elements increases; for example, iodine already exhibits a metallic luster in the solid state, and astatine is expected to be a metal.<ref name="Hermann">{{cite journal
|doi=10.1103/PhysRevLett.111.116404|title=Condensed Astatine: Monatomic and Metallic|year=2013|last1=Hermann|first1=A.|last2=Hoffmann|first2=R.|last3=Ashcroft|first3=N. W.|journal=Physical Review Letters|volume=111|issue=11|pages=116404-1–116404-5|bibcode=2013PhRvL.111k6404H|pmid=24074111}}</ref> As such, an extrapolation based on periodic trends would predict tennessine to be a rather volatile metal.<ref name="GSI">{{cite web |url=https://www.superheavies.de/english/research_program/highlights_element_117.htm |title=Research Program – Highlights |author=GSI |date=14 December 2015 |website=superheavies.de |publisher=GSI |access-date=9 November 2016 |quote=If this trend were followed, element 117 would likely be a rather volatile metal. Fully relativistic calculations agree with this expectation, however, they are in need of experimental confirmation. |archive-date=13 May 2020 |archive-url=https://web.archive.org/web/20200513125453/https://www.superheavies.de/english/research_program/highlights_element_117.htm |url-status=dead }}</ref>

[[File:Valence atomic energy levels for Cl, Br, I, At, and 117.svg|thumb|upright=2.0|Atomic energy levels of outermost ''s'', ''p'', and ''d'' electrons of chlorine (d orbitals not applicable), bromine, iodine, astatine, and tennessine|alt=Black-on-transparent graph, width greater than height, with the main part of the graph being filled with short horizontal stripes]]

Calculations have confirmed the accuracy of this simple extrapolation, although experimental verification of this is currently impossible as the half-lives of the known tennessine isotopes are too short.<ref name="GSI" /> Significant differences between tennessine and the previous halogens are likely to arise, largely due to [[Physics:Spin–orbit interaction|spin–orbit interaction]]—the mutual interaction between the motion and [[Physics:Spin|spin]] of electrons. The spin–orbit interaction is especially strong for the superheavy elements because their electrons move faster—at velocities comparable to the [[Physics:Speed of light|speed of light]]—than those in lighter atoms.{{sfn|Thayer|2010|pp=63–64}} In tennessine atoms, this lowers the 7s and the 7p electron energy levels, stabilizing the corresponding electrons, although two of the 7p electron energy levels are more stabilized than the other four.<ref name="Faegri">{{cite journal | last1 = Fægri Jr. | first1 = K. | last2 = Saue | first2 = T. | doi = 10.1063/1.1385366 | title = Diatomic molecules between very heavy elements of group&nbsp;13 and group&nbsp;17: A study of relativistic effects on bonding | journal = The Journal of Chemical Physics | volume = 115 | issue = 6 | pages = 2456 | year = 2001|bibcode = 2001JChPh.115.2456F | doi-access = free }}</ref> The stabilization of the 7s electrons is called the [[Physics:Inert pair effect|inert pair effect]]; the effect that separates the 7p subshell into the more-stabilized and the less-stabilized parts is called subshell splitting. Computational chemists understand the split as a change of the second ([[Physics:Azimuthal quantum number|azimuthal]]) [[Physics:Quantum number|quantum number]] ''l'' from 1 to 1/2 and 3/2 for the more-stabilized and less-stabilized parts of the 7p subshell, respectively.{{sfn|Thayer|2010|pp=63–67}}{{efn|The quantum number corresponds to the letter in the electron orbital name: 0 to ''s'', 1 to ''p'', 2 to ''d'', etc. See [[Physics:Azimuthal quantum number|azimuthal quantum number]] for more information.}} For many theoretical purposes, the valence electron configuration may be represented to reflect the 7p subshell split as {{Nowrap|7s{{su|p=2|w=70%}}7p{{su|b=1/2|p=2|w=70%}}7p{{su|b=3/2|p=3|w=70%}}}}.<ref name="Haire" />

Differences for other electron levels also exist. For example, the 6d electron levels (also split in two, with four being 6d<sub>3/2</sub> and six being 6d<sub>5/2</sub>) are both raised, so they are close in energy to the 7s ones,<ref name="Faegri" /> although no 6d electron chemistry has ever been predicted for tennessine. The difference between the 7p<sub>1/2</sub> and 7p<sub>3/2</sub> levels is abnormally high; 9.8&nbsp;[[Physics:Electronvolt|eV]].<ref name="Faegri" /> Astatine's 6p subshell split is only 3.8&nbsp;eV,<ref name="Faegri" /> and its 6p<sub>1/2</sub> chemistry has already been called "limited".{{sfn|Thayer|2010|p=79}} These effects cause tennessine's chemistry to differ from those of its upper neighbors (see below).

Tennessine's first [[Physics:Ionization energy|ionization energy]]—the energy required to remove an electron from a neutral atom—is predicted to be 7.7&nbsp;eV, lower than those of the halogens, again following the trend.<ref name="Haire" /> Like its neighbors in the periodic table, tennessine is expected to have the lowest [[Physics:Electron affinity|electron affinity]]—energy released when an electron is added to the atom—in its group; 2.6 or 1.8&nbsp;eV.<ref name="Haire" /> The electron of the hypothetical [[Physics:Hydrogen-like atom|hydrogen-like]] tennessine atom—oxidized so it has only one electron, Ts<sup>116+</sup>—is predicted to move so quickly that its mass is 1.90 times that of a non-moving electron, a feature attributable to [[Chemistry:Relativistic quantum chemistry|relativistic effects]]. For comparison, the figure for hydrogen-like astatine is 1.27 and the figure for hydrogen-like iodine is 1.08.{{sfn|Thayer|2010|p=64}} Simple extrapolations of relativity laws indicate a contraction of [[Physics:Atomic radius|atomic radius]].{{sfn|Thayer|2010|p=64}} Advanced calculations show that the radius of an tennessine atom that has formed one covalent bond would be 165&nbsp;pm, while that of astatine would be 147&nbsp;pm.<ref>{{Cite journal | last1 = Pyykkö | first1 = P. | last2 = Atsumi | first2 = M. | doi = 10.1002/chem.200800987 | pmid = 19058281 | title = Molecular Single-Bond Covalent Radii for Elements 1-118 | journal = Chemistry: A European Journal | volume = 15 | issue = 1 | pages = 186–197 | date = 2008-12-22 }}</ref> With the seven outermost electrons removed, tennessine is finally smaller; 57&nbsp;pm<ref name="Haire" /> for tennessine and 61&nbsp;pm<ref name="India" /> for astatine.

The melting and boiling points of tennessine are not known; earlier papers predicted about 350–500&nbsp;°C and 550&nbsp;°C, respectively,<ref name="Haire" /> or 350–550&nbsp;°C and 610&nbsp;°C, respectively.<ref name="Seaborg">{{cite book |title=Modern alchemy |first=Glenn T. |last=Seaborg |date=1994 |isbn=978-981-02-1440-1 |publisher=World Scientific |page=172 }}</ref> These values exceed those of astatine and the lighter halogens, following [[Chemistry:Periodic trends|periodic trends]]. A later paper predicts the boiling point of tennessine to be 345&nbsp;°C<ref>{{cite journal |journal=Journal of Radioanalytical and Nuclear Chemistry |volume=251 |issue=2 |date=2002 |pages=299–301 |title=Boiling points of the superheavy elements 117 and 118 |first=N. |last=Takahashi |doi=10.1023/A:1014880730282 |s2cid=93096903 }}</ref> (that of astatine is estimated as 309&nbsp;°C,<ref>{{cite book |editor-last=Ullmann |editor-first=F. |title=Encyclopedia of industrial chemistry |date=2005 |publisher=Wiley-VCH |doi=10.1002/14356007.a22_499 |isbn=978-3-527-30673-2 |first1=H. |last1=Luig |first2=C. |last2=Keller |first3=W. |last3=Wolf |first4=J. |last4=Shani |first5=H. |last5=Miska |first6=A. |last6=Zyball |first7=A. |last7=Gervé |first8=A. T. |last8=Balaban |first9=A. M. |last9=Kellerer |first10=J. |last10=Griebel |chapter=Radionuclides |page=23 |display-authors=3 }}</ref> 337&nbsp;°C,<ref>{{cite book |last1=Punter |first1=J. |last2=Johnson |first2=R. |last3=Langfield |first3=S. |title=The essentials of GCSE OCR Additional science for specification B |date=2006 |publisher=Letts and Lonsdale |isbn=978-1-905129-73-7 |page=36 }}</ref> or 370&nbsp;°C,<ref>{{cite book |last1=Wiberg |first1=E. |last2=Wiberg |first2=N. |last3=Holleman |first3=A. F. |title=Inorganic chemistry |url=https://books.google.com/books?id=Mtth5g59dEIC |date=2001 |publisher=Academic Press |isbn=978-0-12-352651-9 |page=423 }}</ref> although experimental values of 230&nbsp;°C<ref name="boiling_point_chromatography">{{cite journal |title=Estimation of the chemical form and the boiling point of elementary astatine by radiogas-chromatography |last1=Otozai |first1=K. |last2=Takahashi |first2=N. |journal=Radiochimica Acta |volume=31 |pages=201‒203 |date=1982 |url=https://www.mendeley.com/research/estimation-chemical-form-boiling-point-elementary-astatine-radio-gas-chromatography/ |issue=3‒4 |doi=10.1524/ract.1982.31.34.201 |s2cid=100363889 }}</ref> and 411&nbsp;°C<ref name="India">{{cite book |first=B. K. |last=Sharma |title=Nuclear and radiation chemistry |url=https://books.google.com/books?id=L8mBZcaGUQAC&pg=PA147 |access-date=2012-11-09 |date=2001 |edition=7th |publisher=Krishna Prakashan Media |isbn=978-81-85842-63-9 |page=147 }}</ref> have been reported). The density of tennessine is expected to be between 7.1 and 7.3&nbsp;g/cm<sup>3</sup>.<ref name="B&K" />

=== Chemical ===
{{multiple image
| align     = right
| direction = horizontal
| width =
| header    =
| image1    = T-shaped-3D-balls.png
| width1    = 180
| alt1      = Skeletal model of a planar molecule with a central atom (iodine) symmetrically bonded to three (fluorine) atoms to form a big right-angled T
| caption1  = {{chem|IF|3}} has a T-shape configuration.
| image2    = Trigonal-3D-balls.png
| width2    = 150
| alt2      = Skeletal model of a trigonal molecule with a central atom (tennessine) symmetrically bonded to three peripheral (fluorine) atoms
| caption2  = {{chem|TsF|3}} is predicted to have a trigonal configuration.
}}

The known isotopes of tennessine, <sup>293</sup>Ts and <sup>294</sup>Ts, are too short-lived to allow for chemical experimentation at present. Nevertheless, many chemical properties of tennessine have been calculated.<ref name="Moody">{{cite book |chapter=Synthesis of Superheavy Elements |last1=Moody |first1=Ken |editor1-first=Matthias |editor1-last=Schädel |editor2-first=Dawn |editor2-last=Shaughnessy |title=The Chemistry of Superheavy Elements |publisher=Springer Science & Business Media |edition=2nd |pages=24–8 |isbn=9783642374661|date=2013-11-30 }}</ref> Unlike the lighter group 17 elements, tennessine may not exhibit the chemical behavior common to the halogens.<ref name="notgonnabeahalogen">{{Cite web|author = <!--no author; by design-->|title = Superheavy Element 117 Confirmed – On the Way to the "Island of Stability"|url = https://www.superheavies.de/english/research_program/highlights_element_117.htm#Is%20Element%20117%20a%20Metal|publisher = GSI Helmholtz Centre for Heavy Ion Research|access-date = 2015-07-26|archive-url = https://web.archive.org/web/20180803133710/https://www.superheavies.de/english/research_program/highlights_element_117.htm#Is%20Element%20117%20a%20Metal|archive-date = 2018-08-03|url-status = dead}}</ref> For example, fluorine, chlorine, bromine, and iodine routinely accept an electron to achieve the more stable electronic configuration of a [[Chemistry:Noble gas|noble gas]], obtaining eight electrons ([[Octet rule|octet]]) in their valence shells instead of seven.<ref>{{cite web |last=Bader |first=R. F. W. |url=https://miranda.chemistry.mcmaster.ca/esam/ |title=An introduction to the electronic structure of atoms and molecules |publisher=McMaster University |access-date=2008-01-18 |archive-date=12 October 2007 |archive-url=https://web.archive.org/web/20071012213137/http://miranda.chemistry.mcmaster.ca/esam/ |url-status=dead }}</ref> This ability weakens as atomic weight increases going down the group; tennessine would be the least willing group 17 element to accept an electron. Of the oxidation states it is predicted to form, −1 is expected to be the least common.<ref name="Haire" /> The standard reduction potential of the Ts/Ts<sup>−</sup> couple is predicted to be −0.25&nbsp;V; this value is negative, unlike for all the lighter halogens.{{Fricke1975}}

There is another opportunity for tennessine to complete its octet—by forming a [[Chemistry:Covalent bond|covalent bond]]. Like the halogens, when two tennessine atoms meet they are expected to form a Ts–Ts bond to give a [[Chemistry:Diatomic molecule|diatomic molecule]]. Such molecules are commonly bound via single [[Chemistry:Sigma bond|sigma bond]]s between the atoms; these are different from [[Chemistry:Pi bond|pi bond]]s, which are divided into two parts, each shifted in a direction perpendicular to the line between the atoms, and opposite one another rather than being located directly between the atoms they bind. Sigma bonding has been calculated to show a great antibonding character in the At<sub>2</sub> molecule and is not as favorable energetically. Tennessine is predicted to continue the trend; a strong pi character should be seen in the bonding of Ts<sub>2</sub>.<ref name="Haire" />{{sfn|Pershina|2010|p=504}} The molecule tennessine chloride (TsCl) is predicted to go further, being bonded with a single pi bond.{{sfn|Pershina|2010|p=504}}

Aside from the unstable −1 state, three more oxidation states are predicted; +5, +3, and +1. The +1 state should be especially stable because of the destabilization of the three outermost 7p<sub>3/2</sub> electrons, forming a stable, half-filled subshell configuration;<ref name="Haire" /> astatine shows similar effects.{{sfn|Thayer|2010|p=84}} The +3 state should be important, again due to the destabilized 7p<sub>3/2</sub> electrons.<ref name="Seaborg" /> The +5 state is predicted to be uncommon because the 7p<sub>1/2</sub> electrons are oppositely stabilized.<ref name="Haire" /> The +7 state has not been shown—even computationally—to be achievable. Because the 7s electrons are greatly stabilized,<!-- While the inert pair effect is the one working here, we can go without it. The whole thing is just a part of the SO interactions the text is mostly talking about. In the contexts not requiring advanced SO talks (indium, lead), the mention of the more obvious inert pair is really enough. Here the context is different from those. We do mention that before --> it has been hypothesized that tennessine effectively has only five valence electrons.<ref name="trifluoride" />

The simplest possible tennessine compound would be the monohydride, TsH. The bonding is expected to be provided by a 7p<sub>3/2</sub> electron of tennessine and the 1s electron of hydrogen. The non-bonding nature of the 7p<sub>1/2</sub> [[Physics:Spinor|spinor]] is because tennessine is expected not to form purely sigma or pi bonds.<ref name="117H" /> Therefore, the destabilized (thus expanded) 7p<sub>3/2</sub> spinor is responsible for bonding.{{sfn|Stysziński|2010|pp=144–146}} This effect lengthens the TsH molecule by 17&nbsp;picometers compared with the overall length of 195&nbsp;pm.<ref name="117H">{{cite journal |journal=Journal of Chemical Physics |title=Spin-orbit effects on the transactinide p-block element monohydrides MH (M=element 113-118) |display-authors=3 |last1=Han |first1=Y.-K. |last2=Bae |first2=Cheolbeom |last3=Son |first3=Sang-Kil |last4=Lee |first4=Yoon Sup |volume=112 |issue=6 |pages=2684–2691 |date=2000 |bibcode=2000JChPh.112.2684H |doi=10.1063/1.480842 |s2cid = 9959620}}</ref> Since the tennessine p electron bonds are two-thirds sigma, the bond is only two-thirds as strong as it would be if tennessine featured no spin–orbit interactions.<ref name="117H" /> The molecule thus follows the trend for halogen hydrides, showing an increase in bond length and a decrease in dissociation energy compared to AtH.<ref name="Haire" /> The molecules [[Chemistry:Thallium|Tl]]Ts and [[Chemistry:Nihonium|Nh]]Ts may be viewed analogously, taking into account an opposite effect shown by the fact that the element's p<sub>1/2</sub> electrons are stabilized. These two characteristics result in a relatively small [[Physics:Electric dipole moment|dipole moment]] (product of difference between electric charges of atoms and [[Displacement (vector)|displacement]] of the atoms) for TlTs; only 1.67&nbsp;D,{{efn|For comparison, the values for the ClF, HCl, SO, HF, and HI molecules are 0.89&nbsp;D, 1.11&nbsp;D, 1.55&nbsp;D, 1.83&nbsp;D, and 1.95&nbsp;D. Values for molecules which do not form at standard conditions, namely GeSe, SnS, TlF, BaO, and NaCl, are 1.65&nbsp;D, ~3.2&nbsp;D, 4.23&nbsp;D, 7.95&nbsp;D, and 9.00&nbsp;D.<ref>{{cite book|first=D. R.|last=Lide |title=CRC Handbook of Chemistry and Physics|edition=84th |publisher=CRC Press|date=2003|chapter=Section 9, Molecular Structure and Spectroscopy|pages=9–45, 9–46|isbn=978-0-8493-0484-2}}</ref>}} the positive value implying that the negative charge is on the tennessine atom. For NhTs, the strength of the effects are predicted to cause a transfer of the electron from the tennessine atom to the nihonium atom, with the dipole moment value being −1.80&nbsp;D.{{sfn|Stysziński|2010|pp=139–146}} The spin–orbit interaction increases the dissociation energy of the TsF molecule because it lowers the electronegativity of tennessine, causing the bond with the extremely electronegative fluorine atom to have a more ionic character.<ref name="117H" /> Tennessine monofluoride should feature the strongest bonding of all group 17 monofluorides.<ref name="117H" />

[[Physics:VSEPR theory|VSEPR theory]] predicts a [[Physics:T-shaped molecular geometry|bent-T-shaped]] [[Physics:Molecular geometry|molecular geometry]] for the group 17 trifluorides. All known halogen trifluorides have this molecular geometry and have a structure of AX<sub>3</sub>E<sub>2</sub>—a central atom, denoted A, surrounded by three [[Chemistry:Ligand|ligand]]s, X, and two unshared [[Physics:Electron pair|electron pair]]s, E. If relativistic effects are ignored, TsF<sub>3</sub> should follow its lighter [[Chemistry:Congener|congeners]] in having a bent-T-shaped molecular geometry. More sophisticated predictions show that this molecular geometry would not be energetically favored for TsF<sub>3</sub>, predicting instead a [[Physics:Trigonal planar molecular geometry|trigonal planar molecular geometry]] (AX<sub>3</sub>E<sub>0</sub>). This shows that VSEPR theory may not be consistent for the superheavy elements.<ref name="trifluoride">{{Cite journal | last1 = Bae | first1 = Ch.| last2 = Han | first2 = Y.-K. | last3 = Lee | first3 = Yo. S. | doi = 10.1021/jp026531m | title = Spin−Orbit and Relativistic Effects on Structures and Stabilities of Group 17 Fluorides EF<sub>3</sub> (E = I, At, and Element 117): Relativity Induced Stability for the ''D<sub>3h</sub>'' Structure of (117)F<sub>3</sub> | journal = The Journal of Physical Chemistry A | volume = 107 | issue = 6 | pages = 852–858 | date = 2003-01-18 | bibcode = 2003JPCA..107..852B }}</ref> The TsF<sub>3</sub> molecule is predicted to be significantly stabilized by spin–orbit interactions; a possible rationale may be the large difference in electronegativity between tennessine and fluorine, giving the bond a partially ionic character.<ref name="trifluoride" />

== Notes ==
{{notelist|35em}}

== References ==
{{reflist}}

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{{refend}}

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