page_title: Oganesson
section_title: Predicted compounds
hierarchical_section_title: Oganesson / Characteristics / Predicted compounds
context_page_description: Oganesson is a synthetic chemical element with the symbol Og and atomic number 118. It was first synthesized in 2002 at the Joint Institute for Nuclear Research in Dubna, near Moscow, Russia, by a joint team of Russian and American scientists. In December 2015, it was recognized as one of four new elements by the Joint Working Party of the international scientific bodies IUPAC and IUPAP. It was formally named on 28 November 2016. The name is in line with the tradition of honoring a scientist, in this case the nuclear physicist Yuri Oganessian, who has played a leading role in the discovery of the heaviest elements in the periodic table. It is one of only two elements named after a person who was alive at the time of naming, the other being seaborgium, and the only element whose namesake is alive today.
  Oganesson has the highest atomic number and highest atomic mass of all known elements. The radioactive oganesson atom is very unstable, and since 2005, only five atoms of the isotope ²⁹⁴Og have been detected.
context_section_description: The only confirmed isotope of oganesson, ²⁹⁴Og, has much too short a half-life to be chemically investigated experimentally. Therefore, no compounds of oganesson have been synthesized yet. Nevertheless, calculations on theoretical compounds have been performed since 1964. 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); nevertheless, this appears not to be the case.
  Calculations on the diatomic molecule Og
  ₂ showed a bonding interaction roughly equivalent to that calculated for Hg
  ₂, and a dissociation energy of 6 kJ/mol, roughly 4 times of that of Rn
  ₂. Most strikingly, it was calculated to have a bond length shorter than in Rn
  ₂ by 0.16 Å, which would be indicative of a significant bonding interaction. On the other hand, the compound OgH⁺ exhibits a dissociation energy (in other words proton affinity of oganesson) that is smaller than that of RnH⁺.
  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. On the other hand, with highly electronegative elements, oganesson seems to form more stable compounds than for example copernicium or flerovium. The stable oxidation states +2 and +4 have been predicted to exist in the fluorides OgF
  ₂ and OgF
  ₄. The +6 state would be less stable due to the strong binding of the 7p1/2 subshell. 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 F
  ₂ to form the compound OgF
  ₂ would release an energy of 106 kcal/mol of which about 46 kcal/mol come from these interactions. For comparison, the spin-orbit interaction for the similar molecule RnF
  ₂ is about 10 kcal/mol out of a formation energy of 49 kcal/mol. The same interaction stabilizes the tetrahedral Td configuration for OgF
  ₄, as distinct from the square planar D₄ₕ one of XeF
  ₄, which RnF
  ₄ is also expected to have; this is because OgF₄ is expected to have two inert electron pairs (7s and 7p1/2). As such, OgF₆ is expected to be unbound, continuing an expected trend in the destabilisation of the +6 oxidation state (RnF₆ is likewise expected to be much less stable than XeF₆). The Og–F bond will most probably be ionic rather than covalent, rendering the oganesson fluorides non-volatile. OgF₂ is predicted to be partially ionic due to oganesson's high electropositivity. Unlike the other noble gases (except possibly xenon and radon), oganesson is predicted to be sufficiently electropositive to form an Og–Cl bond with chlorine.
caption: XeF
  4 has a square planar molecular geometry.
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