View source for Isotopes of oganesson

{{Short description|none}}
{{Infobox oganesson isotopes}}
[[Oganesson]] (<sub>118</sub>Og) is a [[synthetic element]] created in [[particle accelerator]]s, and thus a [[standard atomic weight]] cannot be given. Like all synthetic elements, it has no [[stable isotope]]s. The first and only [[isotope]] to be synthesized was <sup>294</sup>Og in 2002 and 2005; it has a [[half-life]] of 0.7 milliseconds.

== List of isotopes ==
{{Anchor|Oganesson-291|Oganesson-292|Oganesson-293|Oganesson-295}}

<!--Please delete anchor(s) from the list above or table below if adding a dedicated isotope section(s).-->

{{Isotopes table
|symbol=Og
|refs=AME2020 II, NUBASE2020
|notes=unc(), mass#
}}
<!-- |-
| <sup>293</sup>Og
| style="text-align:right" | 118
| style="text-align:right" | 175
| 293.21356(78)#
| 
| 
| 
| -->
|-id=Oganesson-294
| <sup>294</sup>Og
| style="text-align:right" | 118
| style="text-align:right" | 176
| 294.21398(59)#
| {{val|0.58|0.44|0.18|u=ms}}<br />[{{val|0.7|(3)|u=ms}}]
| α
| [[Isotopes of livermorium|<sup>290</sup>Lv]]
| 0+
<!--|-
| <sup>295</sup>Og<ref group="n">Not directly synthesized, occurs in decay chain of [[Isotopes of unbinilium|<sup>299</sup>Ubn]]; unconfirmed</ref>
| style="text-align:right" | 118
| style="text-align:right" | 177
| 295.21624(69)#
| 181&nbsp;ms<ref name="EXON">{{cite conference |title=Remarks on the Fission Barriers of SHN and Search for Element 120 |first1=S. |last1=Hofmann |first2=S. |last2=Heinz |first3=R. |last3=Mann |first4=J. |last4=Maurer |first5=G. |last5=Münzenberg |first6=S. |last6=Antalic |first7=W. |last7=Barth |first8=H. G. |last8=Burkhard |first9=L. |last9=Dahl |first10=K. |last10=Eberhardt |first11=R. |last11=Grzywacz |first12=J. H. |last12=Hamilton |first13=R. A. |last13=Henderson |first14=J. M. |last14=Kenneally |first15=B. |last15=Kindler |first16=I. |last16=Kojouharov |first17=R. |last17=Lang |first18=B. |last18=Lommel |first19=K. |last19=Miernik |first20=D. |last20=Miller |first21=K. J. |last21=Moody |first22=K. |last22=Morita |first23=K. |last23=Nishio |first24=A. G. |last24=Popeko |first25=J. B. |last25=Roberto |first26=J. |last26=Runke |first27=K. P. |last27=Rykaczewski |first28=S. |last28=Saro |first29=C. |last29=Schneidenberger |first30=H. J. |last30=Schött |first31=D. A. |last31=Shaughnessy |first32=M. A. |last32=Stoyer |first33=P. |last33=Thörle-Pospiech |first34=K. |last34=Tinschert |first35=N. |last35=Trautmann |first36=J. |last36=Uusitalo |first37=A. V. |last37=Yeremin |year=2016 |conference=Exotic Nuclei |editor-first1=Yu. E. |editor-last1=Peninozhkevich |editor-first2=Yu. G. |editor-last2=Sobolev |book-title=Exotic Nuclei: EXON-2016 Proceedings of the International Symposium on Exotic Nuclei |pages=155–164 |isbn=9789813226555}}</ref>
| α
| <sup>291</sup>Lv

|-->
{{Isotopes table/footer}}

==Nucleosynthesis==
===Target-projectile combinations leading to Z=118 compound nuclei===
The below table contains various combinations of targets and projectiles that could be used to form compound nuclei with Z=118.{{Citation needed|date=February 2021}}

{| class="wikitable"  style="text-align:center"
! Target !! Projectile !! CN !! Attempt result
|-
! <sup>208</sup>Pb
|<sup>86</sup>Kr || <sup>294</sup>Og || {{No|Failure to date}}
|-
! <sup>238</sup>U
|<sup>58</sup>Fe ||<sup>296</sup>Og || {{unk|Reaction yet to be attempted}}
|-
! <sup>244</sup>Pu
| <sup>54</sup>Cr || <sup>298</sup>Og || {{unk|Reaction yet to be attempted}}
|-
! <sup>248</sup>Cm
|<sup>50</sup>Ti ||<sup>298</sup>Og || {{no|Failure to date}}
|-
! <sup>250</sup>Cm
|<sup>50</sup>Ti ||<sup>300</sup>Og || {{unk|Reaction yet to be attempted}}
|-
! <sup>249</sup>Cf
|<sup>48</sup>Ca ||<sup>297</sup>Og || {{Yes|Successful reaction}}
|-
! <sup>250</sup>Cf
|<sup>48</sup>Ca ||<sup>298</sup>Og || {{No|Failure to date}}
|-
! <sup>251</sup>Cf
|<sup>48</sup>Ca ||<sup>299</sup>Og || {{No|Failure to date}}
|-
! <sup>252</sup>Cf
|<sup>48</sup>Ca ||<sup>300</sup>Og || {{unk|Reaction yet to be attempted}}
|}

===Cold fusion===
====<sup>208</sup>Pb(<sup>86</sup>Kr,''x''n)<sup>294-''x''</sup>Og====
In 1999, a team led by [[Victor Ninov]] at the [[Lawrence Berkeley National Laboratory]] performed this experiment, as a 1998 calculation by [[Robert Smolańczuk]] suggested a promising outcome. After eleven days of irradiation, three events of <sup>293</sup>Og and its [[alpha decay]] products were reported in this reaction; this was the first reported discovery of element 118 and then-unknown [[livermorium|element 116]].<ref name="Transuraniumppl">{{cite book |last1=Hoffman |first1=D.C |last2=Ghiorso |first2=A. |last3=Seaborg |first3=G.T. |title=The Transuranium People: The Inside Story |pages=425–431 |publisher=Imperial College Press |date=2000 |isbn=978-1-86094-087-3}}</ref>

The following year, they published a [[retraction in academic publishing|retraction]] after researchers at other laboratories were unable to duplicate the results and the Berkeley lab could not duplicate them either.<ref>{{cite news|url=http://enews.lbl.gov/Science-Articles/Archive/118-retraction.html|publisher=Berkeley Lab|author=Public Affairs Department|title=Results of element 118 experiment retracted|date=21 July 2001|access-date=18 January 2008|url-status=dead|archive-url=https://web.archive.org/web/20080129191344/http://enews.lbl.gov/Science-Articles/Archive/118-retraction.html|archive-date=29 January 2008|df=dmy-all}}</ref> In June 2002, the director of the lab announced that the original claim of the discovery of these two elements had been based on data fabricated by principal author Victor Ninov.<ref>{{cite journal|pages=728–729|title=Misconduct: The stars who fell to Earth|journal=[[Nature (journal)|Nature]]|volume=420|doi=10.1038/420728a|date=2002|pmid=12490902|last1=Dalton| first1=R.|issue=6917|bibcode = 2002Natur.420..728D |s2cid=4398009 }}</ref><ref>[http://physicsworld.com/cws/article/news/2629 Element 118 disappears two years after it was discovered] {{Webarchive|url=https://web.archive.org/web/20071012075515/http://physicsworld.com/cws/article/news/2629 |date=2007-10-12 }}. Physicsworld.com. Retrieved on 2 April 2012.</ref> Newer experimental results and theoretical predictions have confirmed the exponential decrease in cross-sections with lead and bismuth targets as the atomic number of the resulting nuclide increases.<ref name="Zagrebaev">{{cite journal|title=Future of superheavy element research: Which nuclei could be synthesized within the next few years?|url=http://nrv.jinr.ru/pdf_file/J_phys_2013.pdf|first1=Valeriy|last1=Zagrebaev|first2=Alexander|last2=Karpov|first3=Walter |last3=Greiner|date=2013|journal=Journal of Physics|volume=420|issue=1|pages=012001|doi=10.1088/1742-6596/420/1/012001|arxiv=1207.5700|bibcode=2013JPhCS.420a2001Z|s2cid=55434734 }}</ref>

===Hot fusion===
====<sup>249</sup>Cf(<sup>48</sup>Ca,''x''n)<sup>297-''x''</sup>Og (''x''=3)====
Following successful experiments utilizing [[calcium-48]] projectiles and actinide targets to generate elements [[flerovium|114]] and 116,<ref name="shesummary">{{cite journal|last=Oganessian|first=Y.T.|date=2015|title=Super-heavy element research|url=https://www.researchgate.net/publication/273327193|journal=Reports on Progress in Physics|volume=78|issue=3|pages=036301|doi=10.1088/0034-4885/78/3/036301|pmid=25746203|bibcode=2015RPPh...78c6301O|s2cid=37779526 }}</ref> the search for element 118 was first performed at the [[Joint Institute for Nuclear Research]] (JINR) in 2002. One or two atoms of <sup>294</sup>Og were produced in the 2002 experiment, and two more atoms were produced in a 2005 confirmation run. The discovery of element 118 was announced in 2006.<ref name="synthesis-118-116" />

Because of the very small [[fusion reaction]] probability (the fusion [[nuclear cross section|cross section]] is roughly 0.3–0.6&nbsp;[[Barn (unit)|pb]]), the experiment took four months and involved a beam dose of {{val|2.5|e=19}} [[calcium]] ions that had to be shot at the [[californium]] target to produce the first recorded event believed to be the synthesis of oganesson.<ref name="webelements">{{cite web
 |url=http://www.webelements.com/webelements/elements/text/Uuo/key.html|title=Ununoctium|publisher=WebElements Periodic Table|access-date=2007-12-09}}</ref>
Nevertheless, researchers were highly confident that the results were not a [[false positive]]; the chance that they were random events was estimated to be less than one part in 100,000.<ref>{{cite journal|quote="I would say we're very confident."|url=https://pubs.acs.org/cen/news/84/i43/8443element118.html|title=Element 118 Detected, With Confidence|journal=Chemical & Engineering News|date=17 October 2006|access-date=18 January 2008|author=Jacoby, Mitch |volume=84 |issue=43 |page=11 |doi=10.1021/cen-v084n043.p011 }}</ref>

In a 2012 experiment aimed at the confirmation of [[tennessine]], one alpha decay chain was attributed to <sup>294</sup>Og. This synthesis event resulted from the population of <sup>249</sup>Cf in the target as the decay product of the <sup>249</sup>Bk target (half-life 330 days); the cross section and decays were consistent with previously reported observations of <sup>294</sup>Og.<ref name="shesummary" />

From 1 October 2015 until 6 April 2016, the team at the JINR conducted a search for new isotopes of oganesson using a <sup>48</sup>Ca beam and a target comprising a mixture of <sup>249</sup>Cf (50.7%), <sup>250</sup>Cf (12.9%), and <sup>251</sup>Cf (36.4%). The experiment was performed at 252&nbsp;MeV and 258&nbsp;MeV beam energies. One event of <sup>294</sup>Og was found at the lower beam energy, while no decays of oganesson isotopes were found at the higher beam energy; a cross section of 0.9&nbsp;pb for the <sup>249</sup>Cf(<sup>48</sup>Ca,3n) reaction was estimated.<ref name="mixedCf" />

====<sup>250,251</sup>Cf(<sup>48</sup>Ca,''x''n)<sup>298,299-''x''</sup>Og====
In the 2015–2016 experiment, these reactions were performed in a search for <sup>295</sup>Og and <sup>296</sup>Og. No events attributable to a reaction with the <sup>250</sup>Cf or <sup>251</sup>Cf portions of the target were found. A repeat of this experiment was planned for 2017–2018.<ref name="mixedCf">{{cite journal |last=Voinov |first=A.A. |display-authors=et al. |title=Study of the <sup>249-251</sup>Cf + <sup>48</sup>Ca reactions: recent results and outlook |date=2018 |journal=Journal of Physics: Conference Series |volume=966 |issue=1 |pages=012057 |url=https://www.researchgate.net/publication/318324354 |doi=10.1088/1742-6596/966/1/012057|bibcode=2018JPhCS.966a2057V |doi-access=free }}</ref>

====<sup>248</sup>Cm(<sup>50</sup>Ti,''x''n)<sup>298-''x''</sup>Og====
This reaction was originally planned to be tested at the JINR and [[RIKEN]] in 2017–2018, as it uses the same <sup>50</sup>Ti projectile as planned experiments leading to elements [[ununennium|119]] and [[unbinilium|120]].<ref name="roberto">
{{cite web |url=http://cyclotron.tamu.edu/she2015/assets/pdfs/presentations/Roberto_SHE_2015_TAMU.pdf |title=Actinide Targets for Super-Heavy Element Research |last=Roberto |first=J. B. |date=31 March 2015 |website=cyclotron.tamu.edu |publisher=Texas A & M University |access-date=28 April 2017}}</ref> A search beginning in summer 2016 at RIKEN for <sup>295</sup>Og in the 3n channel of this reaction was unsuccessful, though the study is planned to resume; a detailed analysis and cross section limit were not provided.<ref name="conseil">{{cite conference |last=Hauschild |first=K. |title=Superheavy nuclei at RIKEN, Dubna, and JYFL |date=26 June 2019 |conference=Conseil Scientifique de l'IN2P3 |url=https://in2p3.cnrs.fr/sites/institut_in2p3/files/page/2019-07/6-Pres-HAUSCHILD_-compresse%CC%81.pdf |access-date=31 July 2019}}</ref><ref name="conseil2">{{cite conference |last=Hauschild |first=K. |title=Heavy nuclei at RIKEN, Dubna, and JYFL |date=2019 |conference=Conseil Scientifique de l'IN2P3 |url=https://in2p3.cnrs.fr/sites/institut_in2p3/files/page/2019-07/6-Doc-HAUSCHILD-comp.pdf |access-date=1 August 2019}}</ref>

==Theoretical calculations==
Theoretical calculations done on the synthetic pathways for, and the half-life of, other isotopes have shown that some could be slightly more stable than the synthesized isotope <sup>294</sup>Og, most likely <sup>293</sup>Og, <sup>295</sup>Og, <sup>296</sup>Og, <sup>297</sup>Og, <sup>298</sup>Og, <sup>300</sup>Og and <sup>302</sup>Og.<ref name="half-lifes">{{cite journal |journal=Physical Review C |volume=73 |issue=1 |pages=014612 |date= January 26, 2006 |title=α decay half-lives of new superheavy elements |author=P. Roy Chowdhury |author2=C. Samanta |author3=D. N. Basu |url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000073000001014612000001&idtype=cvips&gifs=yes |access-date=2008-01-18 |doi = 10.1103/PhysRevC.73.014612 |arxiv = nucl-th/0507054 |bibcode = 2006PhRvC..73a4612C |s2cid=118739116 }}</ref><ref>{{cite journal |journal=Nuclear Physics A |volume=789 |date= April 6, 2007 |issue=1–4 |pages=142–154 |title=Predictions of alpha decay half lives of heavy and superheavy elements |author=C. Samanta |author2=P. Roy Chowdhury |author3=D. N. Basu |doi=10.1016/j.nuclphysa.2007.04.001 |bibcode=2007NuPhA.789..142S |arxiv = nucl-th/0703086 |citeseerx=10.1.1.264.8177 |s2cid=7496348 }}</ref><ref name="odd">{{cite journal |journal=Nuclear Physics A |volume=730 |year=2004 |issue=3–4 |pages=355–376 |title=Entrance channels and alpha decay half-lives of the heaviest elements |author=G. Royer |author2=K. Zbiri |author3=C. Bonilla |doi=10.1016/j.nuclphysa.2003.11.010 |bibcode=2004NuPhA.730..355R |arxiv = nucl-th/0410048 }}</ref> Of these, <sup>297</sup>Og might provide the best chances for obtaining longer-lived nuclei,<ref name="half-lifes" /><ref name="odd" /> and thus might become the focus of future work with this element. Some isotopes with many more neutrons, such as some located around <sup>313</sup>Og, could also provide longer-lived nuclei.<ref>{{cite journal |title=Half-life predictions for decay modes of superheavy nuclei |year=2004 |journal=Journal of Physics G: Nuclear and Particle Physics |volume=30 |issue=10 |pages=1487–1494 |doi=10.1088/0954-3899/30/10/014 |author=S. B. Duarte |author2=O. A. P. Tavares |author3=M. Gonçalves |author4=O. Rodríguez |author5=F. Guzmán |author6=T. N. Barbosa |author7=F. García |author8=A. Dimarco |bibcode=2004JPhG...30.1487D|citeseerx=10.1.1.692.3012 }}</ref>

===Theoretical calculations on evaporation cross sections ===
The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.

DNS = Di-nuclear system; 2S = Two-step; σ = cross section

{| class="wikitable"  style="text-align:center"
|-
! Target !! Projectile !! CN !! Channel (product) !! σ <sub>max</sub> !! Model !! Ref
|-
! <sup>208</sup>Pb
| <sup>86</sup>Kr ||<sup>294</sup>Og || 1n (<sup>293</sup>Og) ||0.1&nbsp;pb ||DNS || <ref name="FengColdFusion">{{cite journal |doi=10.1103/PhysRevC.76.044606 |title=Formation of superheavy nuclei in cold fusion reactions |year=2007 |last1=Feng |first1=Zhao-Qing |journal=Physical Review C |volume=76 |issue=4 |pages=044606 |last2=Jin |first2=Gen-Ming |last3=Li |first3=Jun-Qing |last4=Scheid |first4=Werner |bibcode=2007PhRvC..76d4606F |arxiv = 0707.2588 |s2cid=711489 }}</ref>
|-
! <sup>208</sup>Pb
| <sup>85</sup>Kr ||<sup>293</sup>Og || 1n (<sup>292</sup>Og) ||0.18&nbsp;pb ||DNS || <ref name="FengColdFusion" />
|-
! <sup>246</sup>Cm
| <sup>50</sup>Ti ||<sup>296</sup>Og || 3n (<sup>293</sup>Og) ||40&nbsp;fb ||2S || <ref name="LiuTwoStep">{{cite journal|last1=Liu|first1=L.|last2=Shen|first2=C.|last3=Li|first3=Q.|last4=Tu|first4=Y.|last5=Wang |first5=X.|last6=Wang|first6=Y.|date=2016|title=Residue cross sections of <sup>50</sup>Ti-induced fusion reactions based on the two-step model|journal=[[European Physical Journal A]]|volume=52|issue=35|page=35 |doi=10.1140/epja/i2016-16035-0|arxiv=1512.06504|bibcode=2016EPJA...52...35L |s2cid=254116073 }}</ref>
|-
! <sup>244</sup>Cm
| <sup>50</sup>Ti ||<sup>294</sup>Og || 2n (<sup>292</sup>Og) ||53&nbsp;fb ||2S || <ref name="LiuTwoStep" />
|-
! <sup>252</sup>Cf
| <sup>48</sup>Ca ||<sup>300</sup>Og || 3n (<sup>297</sup>Og) ||1.2&nbsp;pb ||DNS || <ref name="FengHotFusion">{{cite journal |doi=10.1016/j.nuclphysa.2008.11.003 |title=Production of heavy and superheavy nuclei in massive fusion reactions |year=2009 |last1=Feng |first1=Z |journal=Nuclear Physics A |volume=816 |issue=1–4 |pages=33–51 |last2=Jin |first2=G |last3=Li |first3=J |last4=Scheid |first4=W |bibcode=2009NuPhA.816...33F |arxiv = 0803.1117 |s2cid=18647291 }}</ref>
|-
! <sup>251</sup>Cf
| <sup>48</sup>Ca ||<sup>299</sup>Og || 3n (<sup>296</sup>Og) ||1.2&nbsp;pb ||DNS || <ref name="FengHotFusion" />
|-
! <sup>249</sup>Cf
| <sup>48</sup>Ca ||<sup>297</sup>Og || 3n (<sup>294</sup>Og) ||0.3&nbsp;pb ||DNS || <ref name="FengHotFusion" />
|}

== References ==
{{reflist}}
{{Navbox element isotopes}}

[[Category:Isotopes of oganesson| ]]
[[Category:Oganesson]]
[[Category:Lists of isotopes by element|oganesson]]