Editing Tennessine (section)

== 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|Isotopes of tennessine}}
{{see also|Island of stability}}

The stability of nuclei quickly decreases with the increase in atomic number after [[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 [[mendelevium|101]] undergo radioactive decay with half-lives of less than 30 hours. No elements with atomic numbers above 82 (after [[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 |s2cid-access=free |url=http://web.mit.edu/8.13/8.13c/references-fall/alphadecay/marcillac-bi209-alpha-decay-nature-2003.pdf |via=MIT |journal=Nature |volume=422 |pages=876–878 |pmid=12712201 |doi=10.1038/nature01541 |issue=6934 |bibcode=2003Natur.422..876D |s2cid=4415582 |url-status=live |archive-url=https://web.archive.org/web/20221211103340/http://web.mit.edu/8.13/8.13c/references-fall/alphadecay/marcillac-bi209-alpha-decay-nature-2003.pdf |archive-date= Dec 11, 2022 }}</ref> This is because of the ever-increasing Coulomb repulsion of protons, so that the [[strong nuclear force]] cannot hold the nucleus together against [[spontaneous fission]] for long. Calculations suggest that in the absence of other stabilizing factors, elements with more than [[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 |via=INSPIRE |doi=10.1051/epjconf/201613103002 |bibcode=2016EPJWC.13103002M|doi-access=free |bibcode-access=free |url-status=live |archive-url=https://web.archive.org/web/20250122114150/https://www.epj-conferences.org/articles/epjconf/pdf/2016/26/epjconf-NS160-03002.pdf |archive-date= Jan 22, 2025 }}</ref> However, researchers in the 1960s suggested that the closed [[nuclear shell model|nuclear shells]] around 114&nbsp;protons and 184&nbsp;neutrons should counteract this instability, creating an "[[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 [[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]]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> This isotope could also be produced in a pxn channel of the <sup>249</sup>Cf+<sup>48</sup>Ca reaction that successfully produced oganesson, evaporating a proton alongside some neutrons; the heavier tennessine isotopes <sup>296</sup>Ts and <sup>297</sup>Ts could similarly be produced in the <sup>251</sup>Cf+<sup>48</sup>Ca reaction.<ref name=Yerevan2023PPT>{{cite conference |url=https://indico.jinr.ru/event/3622/contributions/20021/attachments/15292/25806/Yerevan2023.pdf |title=Interesting fusion reactions in superheavy region |first1=J. |last1=Hong |first2=G. G. |last2=Adamian |first3=N. V. |last3=Antonenko |first4=P. |last4=Jachimowicz |first5=M. |last5=Kowal |conference=IUPAP Conference "Heaviest nuclei and atoms" |publisher=Joint Institute for Nuclear Research |date=26 April 2023 |access-date=30 July 2023}}</ref><ref name=pxn>{{cite journal |last1=Hong |first1=J. |last2=Adamian |first2=G. G. |last3=Antonenko |first3=N. V. |date=2017 |title=Ways to produce new superheavy isotopes with ''Z''&nbsp;=&nbsp;111–117 in charged particle evaporation channels |journal=Physics Letters B |volume=764 |pages=42–48 |doi=10.1016/j.physletb.2016.11.002 |bibcode=2017PhLB..764...42H|doi-access=free }}</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 [[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-life|partial half-lives]] exceeding the [[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 |archive-date=1 October 2016 |archive-url=https://web.archive.org/web/20161001224516/http://nuclphys.sinp.msu.ru/nseminar/12.02.08.pdf |url-status=dead }}</ref> the isotopes <sup>289</sup>Ts through <sup>292</sup>Ts could also be produced as daughters of [[ununennium|element 119]] isotopes that can be produced in the <sup>243</sup>Am+<sup>54</sup>Cr and <sup>249</sup>Bk+<sup>50</sup>Ti reactions.<ref name=jinr2024>{{Cite web |url=https://indico.jinr.ru/event/4343/contributions/28663/attachments/20748/36083/U%20+%20Cr%20AYSS%202024.pptx |title=Synthesis and study of the decay properties of isotopes of superheavy element Lv in Reactions <sup>238</sup>U + <sup>54</sup>Cr and <sup>242</sup>Pu + <sup>50</sup>Ti |last=Ibadullayev |first=Dastan |date=2024 |website=jinr.ru |publisher=[[Joint Institute for Nuclear Research]] |access-date=2 November 2024 |quote=}}</ref>
{{Clear}}

===Atomic and physical===
Tennessine is expected to be a member of group 17 in the periodic table, below the five halogens; [[fluorine]], [[chlorine]], [[bromine]], [[iodine]], and [[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 (chemistry)|period]] (horizontal row in the periodic table) the element belongs to. The letters "s" and "p" denote the ''s'' and ''p'' [[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 (chemistry)|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|class=skin-invert-image|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 [[spin–orbit interaction]]—the mutual interaction between the motion and [[Spin (physics)|spin]] of electrons. The spin–orbit interaction is especially strong for the superheavy elements because their electrons move faster—at velocities comparable to the [[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 [[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 ([[azimuthal quantum number|azimuthal]]) [[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 [[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;[[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 [[#Chemical|below]]).

Tennessine's first [[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 [[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 [[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 [[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 [[atomic radius]].{{sfn|Thayer|2010|p=64}} Advanced calculations show that the radius of a tennessine atom that has formed one covalent bond would be 165&nbsp;[[picometer|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 |author-link=Glenn T. Seaborg |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 [[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 |bibcode=2002JRNC..251..299T |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 [[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 [[covalent bond]]. Like the halogens, when two tennessine atoms meet they are expected to form a Ts–Ts bond to give a [[diatomic molecule]]. Such molecules are commonly bound via single [[sigma bond]]s between the atoms; these are different from [[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> [[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 [[thallium|Tl]]Ts and [[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 [[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;[[debye (unit)|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 bond|ionic]] character.<ref name="117H" /> Tennessine monofluoride should feature the strongest bonding of all group 17 monofluorides.<ref name="117H" />

[[VSEPR theory]] predicts a [[T-shaped molecular geometry|bent-T-shaped]] [[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 [[ligand]]s, X, and two unshared [[electron pair]]s, E. If relativistic effects are ignored, TsF<sub>3</sub> should follow its lighter [[Congener (chemistry)|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 [[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" />