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Oganesson is a synthetic chemical element with symbol Og and atomic number 118. 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 (possibly six) atoms of the isotope oganesson-294 have been created.


The element is named in honor of Yuri Oganessian. It was first created in 2002 at the Joint Institute for Nuclear Research (JINR) in Dubna, 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 people at IUPAC and IUPAP. It was formally named on 28 November 2016.[1] It had a previous name given by the IUPAC called "Ununoctium" meaning "one-one-eight" in Latin. This was a placeholder name until the element was discovered and a name was given. The possibility of a seventh noble gas, after helium, neon, argon, krypton, xenon, and radon, was considered almost as soon as the noble gas group was discovered. Danish chemist Hans Peter Jørgen Julius Thomsen predicted in April 1895, the year after the discovery of argon, that there was a whole group of chemically unreactive gases similar to argon that would link the halogen and alkali metal groups. He expected that the seventh of this series would end a 32-element period which contained elements like thorium and uranium and have an atomic weight of 292, close to the 294 now known for the first and only confirmed isotope of oganesson.


The chemistry of Oganesson can not be found because of how radioactive it is and how short its half-life is, which is only 0.69 milliseconds. However, predictions can be made based on properties the group has in common with each other. Since its a noble gas, it is predited that its going to be a diatomic molecule (it only pairs with itself).


Oganesson,  118Og
General properties
Mass number294 (most stable isotope) (unconfirmed: 295)
Oganesson in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Atomic number (Z)118
Groupgroup 18
Periodperiod 7
Element category  noble gas (predicted)
Electron configuration[Rn] 5f14 6d10 7s2 7p6 (predicted)[3][4]
Electrons per shell
2, 8, 18, 32, 32, 18, 8 (predicted)
Physical properties
Phase at STPOg: Unknown phase (predicted)[3]
Boiling point350±30 K ​(80±30 °C, ​170±50 °F) (extrapolated)[3]
Density when liquid (at m.p.)4.9–5.1 g/cm3 (predicted)[5]
Critical point439 K, 6.8 MPa (extrapolated)[6]
Heat of fusion23.5 kJ/mol (extrapolated)[6]
Heat of vaporization19.4 kJ/mol (extrapolated)[6]
Atomic properties
Oxidation states(−1),[4] (0), (+1),[7] (+2),[8] (+4),[8] (+6)[4] (predicted)
Ionization energies
  • 1st: 860.1 kJ/mol (predicted)[9]
  • 2nd: 1560 kJ/mol (predicted)[10]
Covalent radius157 pm (predicted)[11]
Other properties
Natural occurrenceOg: Synthetic
Crystal structureface-centered cubic (fcc)
Face-centered cubic crystal structure for oganesson

CAS Number54144-19-3
Namingafter Yuri Oganessian
PredictionNiels Bohr (1922)
DiscoveryJoint Institute for Nuclear Research and Lawrence Livermore National Laboratory (2002)
Main isotopes of oganesson
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
294Og[13] syn 0.69 ms[14] α 290Lv
295Og[15] syn 181 ms? α 291Lv
| references

It currently has no use because of how radioactive and short its half life is.

Other websites


  1. Staff (30 November 2016). "IUPAC Announces the Names of the Elements 113, 115, 117, and 118". IUPAC. Retrieved 1 December 2016. 
  2. Ritter, Malcolm (9 June 2016). Periodic table elements named for Moscow, Japan, Tennessee. Associated Press. Retrieved 19 December 2017. 
  3. 3.0 3.1 3.2 3.3 Nash, Clinton S. (2005). "Atomic and Molecular Properties of Elements 112, 114, and 118". Journal of Physical Chemistry A 109 (15): 3493–3500. doi:10.1021/jp050736o . PMID 16833687 . 
  4. 4.0 4.1 4.2 4.3 Hoffman, Darleane C.; Lee, Diana M.; Pershina, Valeria (2006). "Transactinides and the future elements". In Morss; Edelstein, Norman M.; Fuger, Jean. The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media. ISBN 1-4020-3555-1 . 
  5. Bonchev, Danail; Kamenska, Verginia (1981). "Predicting the Properties of the 113–120 Transactinide Elements". Journal of Physical Chemistry (American Chemical Society) 85 (9): 1177–1186. doi:10.1021/j150609a021 . 
  6. 6.0 6.1 6.2 Eichler, R.; Eichler, B., Thermochemical Properties of the Elements Rn, 112, 114, and 118, Paul Scherrer Institut,, retrieved 2010-10-23 
  7. Han, Young-Kyu; Bae, Cheolbeom; Son, Sang-Kil; Lee, Yoon Sup (2000). "Spin–orbit effects on the transactinide p-block element monohydrides MH (M=element 113–118)". Journal of Chemical Physics 112 (6): 2684. doi:10.1063/1.480842 . 
  8. 8.0 8.1 Kaldor, Uzi; Wilson, Stephen (2003). Theoretical Chemistry and Physics of Heavy and Superheavy Elements. Springer. p. 105. ISBN 140201371X .,M1. Retrieved 2008-01-18. 
  9. Pershina, Valeria. "Theoretical Chemistry of the Heaviest Elements". In Schädel, Matthias; Shaughnessy, Dawn. The Chemistry of Superheavy Elements (2nd ed.). Springer Science & Business Media. p. 154. ISBN 9783642374661 . 
  10. Fricke, Burkhard (1975). "Superheavy elements: a prediction of their chemical and physical properties". Recent Impact of Physics on Inorganic Chemistry 21: 89–144. doi:10.1007/BFb0116498 . Retrieved 4 October 2013. 
  11. Chemical Data. Ununoctium - Uuo, Royal Chemical Society
  12. Grosse, A. V. (1965). "Some physical and chemical properties of element 118 (Eka-Em) and element 86 (Em)". Journal of Inorganic and Nuclear Chemistry (Elsevier Science Ltd.) 27 (3): 509–19. doi:10.1016/0022-1902(65)80255-X . 
  13. Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Tsyganov, Yu. S. et al. (2006-10-09). "Synthesis of the isotopes of elements 118 and 116 in the 249Cf and 245Cm+48Ca fusion reactions". Physical Review C 74 (4): 044602. doi:10.1103/PhysRevC.74.044602 . Retrieved 2008-01-18. 
  14. Oganessian, Yuri Ts.; Rykaczewski, Krzysztof P. (August 2015). "A beachhead on the island of stability". Physics Today 68 (8): 32–38. doi:10.1063/PT.3.2880 . Retrieved 2017-06-14. 
  15. (2016) "Remarks on the Fission Barriers of SHN and Search for Element 120" in Exotic Nuclei. : 155–164.