Editing Oganesson (section)

===Predicted compounds===
[[File:Square-planar-3D-balls.png|right|upright=0.6|alt=Skeletal model of a planar molecule with a central atom symmetrically bonded to four peripheral (fluorine) atoms.|thumb|[[xenon tetrafluoride|{{chem|XeF|4}}]] has a square planar molecular geometry.]]
[[File:Tetrahedral-3D-balls.png|right|upright=0.6|thumb|alt=Skeletal model of a terahedral molecule with a central atom (oganesson) symmetrically bonded to four peripheral (fluorine) atoms.|{{chem|OgF|4}} is predicted to have a tetrahedral molecular geometry.]]

The only confirmed isotope of oganesson, <sup>294</sup>Og, has much too short a half-life to be chemically investigated experimentally. Therefore, no compounds of oganesson have been synthesized yet.<ref name="Moody">{{cite book |chapter=Synthesis of Superheavy Elements |last=Moody |first=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=30 November 2013 }}</ref> Nevertheless, calculations on [[theoretical chemistry|theoretical compounds]] have been performed since 1964.<ref name="60s"/> It is expected that if the [[ionization energy]] of the element is high enough, it will be difficult to [[oxidize]] and therefore, the most common [[oxidation state]] would be 0 (as for the noble gases);<ref name="compounds">{{cite web|publisher=WebElements Periodic Table|url=https://www.webelements.com/oganesson/compounds.html|title=Oganesson: Compounds Information|access-date=19 August 2019}}</ref> nevertheless, this appears not to be the case.{{Fricke1975|name}}

Calculations on the [[diatomic molecule]] {{chem|Og|2}} showed a [[chemical bond|bonding]] interaction roughly equivalent to that calculated for {{chem|Hg|2}}, and a [[dissociation energy]] of 6&nbsp;kJ/mol, roughly 4 times of that of {{chem|Rn|2}}.<ref name="Nash2005"/> Most strikingly, it was calculated to have a [[bond length]] shorter than in {{chem|Rn|2}} by 0.16 Å, which would be indicative of a significant bonding interaction.<ref name="Nash2005"/> On the other hand, the compound OgH<sup>+</sup> exhibits a dissociation energy (in other words [[proton affinity]] of oganesson) that is smaller than that of RnH<sup>+</sup>.<ref name="Nash2005"/>

The bonding between oganesson and [[hydrogen]] in OgH is predicted to be very weak and can be regarded as a pure [[van der Waals interaction]] rather than a true [[chemical bond]].<ref name="hydride"/> On the other hand, with highly electronegative elements, oganesson seems to form more stable compounds than for example [[copernicium]] or [[flerovium]].<ref name="hydride"/> The stable oxidation states +2 and +4 have been predicted to exist in the [[fluoride]]s {{chem|OgF|2}} and {{chem|OgF|4}}.<ref name="fluoride">{{cite journal|journal=Journal of Physical Chemistry A|volume=103|issue=8|pages=1104–1108|date=1999|title=Structures of RgFn (Rg = Xe, Rn, and Element 118. n = 2, 4.) Calculated by Two-component Spin-Orbit Methods. A Spin-Orbit Induced Isomer of (118)F<sub>4</sub>|first1=Young-Kyu|last1=Han|first2=Yoon Sup|last2=Lee|doi=10.1021/jp983665k|bibcode=1999JPCA..103.1104H}}</ref> The +6 state would be less stable due to the strong binding of the 7p<sub>1/2</sub> subshell.{{Fricke1975|name}} This is a result of the same spin–orbit interactions that make oganesson unusually reactive. For example, it was shown that the reaction of oganesson with {{chem|F|2}} to form the compound {{chem|OgF|2}} would release an energy of 106&nbsp;kcal/mol of which about 46&nbsp;kcal/mol come from these interactions.<ref name="hydride"/> For comparison, the spin–orbit interaction for the similar molecule {{chem|RnF|2}} is about 10&nbsp;kcal/mol out of a formation energy of 49&nbsp;kcal/mol.<ref name="hydride"/> The same interaction stabilizes the [[tetrahedral molecular geometry|tetrahedral T<sub>d</sub> configuration]] for {{chem|OgF|4}}, as distinct from the [[square planar|square planar D<sub>4h</sub> one]] of [[xenon tetrafluoride|{{chem|XeF|4}}]], which {{chem|RnF|4}} is also expected to have;<ref name="fluoride"/> this is because OgF<sub>4</sub> is expected to have two [[inert pair|inert electron pairs]] (7s and 7p<sub>1/2</sub>). As such, OgF<sub>6</sub> is expected to be unbound, continuing an expected trend in the destabilisation of the +6 oxidation state (RnF<sub>6</sub> is likewise expected to be much less stable than [[xenon hexafluoride|XeF<sub>6</sub>]]).<ref>{{cite journal |last=Liebman |first=Joel F. |date=1975 |title=Conceptual Problems in Noble Gas and Fluorine Chemistry, II: The Nonexistence of Radon Tetrafluoride |journal=Inorg. Nucl. Chem. Lett. |volume=11 |issue=10 |pages=683–685 |doi=10.1016/0020-1650(75)80185-1}}</ref><ref>{{cite journal |last=Seppelt |first=Konrad |date=2015 |title=Molecular Hexafluorides |journal=Chemical Reviews |volume=115 |issue=2 |pages=1296–1306 |doi=10.1021/cr5001783|pmid=25418862 }}</ref> The Og–F bond will most probably be [[ionic bond|ionic]] rather than [[covalent bond|covalent]], rendering the oganesson fluorides non-volatile.<ref name="Kaldor"/><ref>{{cite journal|journal=Journal of the Chemical Society, Chemical Communications|date=1975|pages=760–761|doi=10.1039/C3975000760b|title=Fluorides of radon and element 118|first =Kenneth S.|last = Pitzer|issue=18|url=https://escholarship.org/content/qt8xz4g1ff/qt8xz4g1ff.pdf?t=p2at3t}}</ref> OgF<sub>2</sub> is predicted to be partially [[ionic bonding|ionic]] due to oganesson's high [[electropositivity]].<ref name="EB">{{cite encyclopedia |title=transuranium element (chemical element) |encyclopedia=[[Encyclopædia Britannica|Britannica Online]] |url=https://www.britannica.com/EBchecked/topic/603220/transuranium-element |access-date=16 March 2010 |date=c. 2006 |author=Seaborg, Glenn Theodore}}</ref> Oganesson is predicted to be sufficiently electropositive<ref name="EB"/> to form an Og–Cl bond with [[chlorine]].<ref name="Kaldor"/>

A compound of oganesson and [[tennessine]], OgTs<sub>4</sub>, has been predicted to be potentially stable chemically.<ref name="Loveland">{{cite journal |last=Loveland |first=Walter |title=Relativistic effects for the superheavy reaction Og + 2Ts2 → OgTs4 (Td or D4h): dramatic relativistic effects for atomization energy of superheavy Oganesson tetratennesside OgTs4 and prediction of the existence of tetrahedral OgTs4 |journal=Theoretical Chemistry Accounts |date=1 June 2021 |volume=140 |issue=75 |doi=10.1007/s00214-021-02777-2 |osti=1991559 |s2cid=235259897 |url=https://link.springer.com/article/10.1007/s00214-021-02777-2 |access-date=30 June 2021}}</ref>