Oganesson - element symbol Og - is the international name for the chemical element with atomic number 118 approved by IUPAC since November 2016.
The proposed name comes from the discoverers of the element and honors the Russian nuclear physicist Professor Yuri Oganessian for his pioneering work in the field of research into the superheavy elements and the transactinides.
The suffix -on was chosen because the element, as a member of the eighth main group of the periodic table, belongs to the noble gases and these - with the exception of helium - also end in -on (neon, argon, etc.).
Oganesson is an artificial, super-heavy, unstable and therefore radioactive element whose isotopes that have been detected so far are very short-lived with a half-life in the microsecond range. Employment and research on this element is for academic purposes only; there are no technical or other practical applications.
The chemical element is currently at the end of the periodic table, i.e. no atoms are known or proven that have a higher atomic mass and no higher atomic number.
Up until now only three or four oganesson atoms could be produced by bombarding 249Cf californium isotopes with 48Ca calcium nuclei, which required an enormous amount of equipment was necessary:
4820Ca + 24998Cf → 294118Og + 3 10n.
In December 2015, a joint working group of international scientific bodies from the International Union for Pure and Applied Chemistry (IUPAC) and the International Union for Pure and Applied Physics (IUPAP) recognized the discovery of the element and assigned the rights to the discovery to the two nuclear research centers in Dubna (Russia) and Livermore (USA).
The few atoms produced and their short lifespan allow only limited statements about the chemical characteristics of the oganesson. Theoretical calculations and relativistic effects allow the statement that the element does not behave like an inert gas and does not follow the periodic trends - and therefore forms a solid under normal conditions and behaves like a p-block element. Or there is even a loss of shell structure; Oganesson may have reached a point where the electrons form an evenly distributed charged gas. Such an effect would significantly affect the properties of the element ...
Once generated, oganesson rapidly decays to Livermorium-290 with the emission of α-rays and with a half-life of about 0.7 ms:
The electron configuration of oganesson in the uncharged ground state is:
Abbreviated form: [Rn] 5f14 6d10 7s2 7p6.
The following table lists the ionization energies IE (ionization potentials); the IE is the energy required in electron volts (eV) per atom to separate a given electron from an Oganesson atom.
Data source: see .
An overview of the nuclides as well as the isotopic data and properties are listed on the following page: Oganesson isotopes.
The ongoing data are estimates or rough predictions based in particular on the position in the periodic table. It is not to be expected that more precise data and properties of the oganesson can be measured in the near future. The listing here is for the sake of completeness [cf. also 4].
 - Yu. Ts. Oganessian et al.:
Synthesis of the isotopes of elements 118 and 116 in the 249Cf and 245Cm + 48Ca fusion reactions.
In: Physical Review C, (2006), DOI 10.1103/PhysRevC.74.044602.
 - Richard Van Noorden:
Four new element names proposed for periodic table.
In: Nature, (2016), DOI 10.1038/nature.2016.20069.
 - Kit Chapman:
The Oganesson Odyssey.
In: Nature Chemistry, (2018), DOI 10.1038/s41557-018-0098-4.
 - Dr. Odile R. Smits et al.:
Oganesson: A Noble Gas Element That Is Neither Noble Nor a Gas.
In: Angewandte Chemie International Edition, (2020), DOI 10.1002/anie.202011976.
 - Yangyang Guo, Lukáš F.Pašteka, Ephraim Eliav, Anastasia Borschevsky:
Chapter Five - Ionization potentials and electron affinity of oganesson with relativistic coupled cluster method.
In: Chapter Five - Ionization potentials and electron affinity of oganesson with relativistic coupled cluster method, (2021), DOI 10.1016/bs.aiq.2021.05.007.
Last update: 2022-11-27
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