Oganesson / Ununoctium Element Facts

Ununoctium Radioactive

A combination of experiments and computer simulations enable predictions to be made of deformations and shapes of the heaviest elements in and beyond the current periodic table. Image Ref. (2)


Data Zone

Classification: Oganesson / Ununoctium is a noble gas
(or a noble solid?) and a nonmetal
Atomic weight: (294), no stable isotopes
State: gas (presumed)
Melting point:
Boiling point:
Electrons: 118
Protons: 118
Neutrons in most abundant isotope: 176
Electron shells: 2, 8, 18, 32, 32, 18, 8
Electron configuration: [Rn] 5f14 6d10 7s2 7p6 (presumed)
Show more, including: Heats, Energies, Oxidation, Reactions, Compounds, Radii, Conductivities
Specific heat capacity
Heat of fusion
Heat of atomization
Heat of vaporization
1st ionization energy
2nd ionization energy
3rd ionization energy
Electron affinity
Minimum oxidation number
Min. common oxidation no.
Maximum oxidation number
Max. common oxidation no.
Electronegativity (Pauling Scale)
Polarizability volume
Reaction with air
Reaction with 15 M HNO3
Reaction with 6 M HCl
Reaction with 6 M NaOH
Atomic radius
Ionic radius (1+ ion)
Ionic radius (2+ ion)
Ionic radius (3+ ion)
Ionic radius (1- ion)
Ionic radius (2- ion)
Ionic radius (3- ion)
Thermal conductivity
Electrical conductivity
Freezing/Melting point:

The cyclotron at Dubna

The heavy ion cyclotron U-400 in Dubna, where oganesson was synthesized.

Discovery of Oganesson

Dr. Doug Stewart

Research scientists at the Joint Institute for Nuclear Research in Dubna, Russia and the Lawrence Livermore National Laboratory (LLNL), California first made element 118, oganesson, in 2002.

The reaction was a fusion of element 20 with element 98: calcium-48 with californium-249.

Calcium ions were formed into a beam in a cyclotron (a particle accelerator) and fired at a target layer of californium oxide deposited on titanium foil.

Bombardment lasted 2300 hours, accumulating a total dose of 2.5 x 1019 calcium ions.

Two atoms of oganesson-294, which existed for 2.55 ms and 3.16 ms, were produced in March 2002. (1)

Further experiments and analysis later confirmed this result and the discovery was verified by The International Union of Pure and Applied Chemistry (IUPAC) in 2015.

The report stated, “The claim of the Dubna–Livermore 2006 collaboration for discovery of the element with atomic number Z=18 is acknowledged as validated..”

As a result of its position in the periodic table oganesson is expected to be classed as a noble gas.

The element is named after the Russian Professor Yuri Oganessian, for his pioneering contributions to transactinoid elements research. Oganesson, with chemical symbol Og, is expected to officially replace its temporary name, ununoctium, later this year.

IUPAC has accepted the discoveries of element 113 (nihonium/ununtrium), element 114 (flerovium/ununquadium), element 115 (moscovium/ununpentium), element 116 (livermorium/ununhexium), element 117 (tennessine/ununseptium) and element 118 (oganesson/ununoctium), thus completing the seventh row of the periodic table.

Appearance and Characteristics

Harmful effects:

Oganesson / Ununoctium is harmful due to its radioactivity.


Oganesson is a synthetic radioactive metal and has only been produced in minute amounts.

Uses of Oganesson

Oganesson is of research interest only.

Abundance and Isotopes

Abundance earth’s crust: nil

Abundance solar system: parts per trillion by weight, parts per trillion by moles

Cost, pure: $ per 100g

Cost, bulk: $ per 100g

Source: A few atoms oganesson have been created via nuclear bombardment of 249Cf with 48Ca ions in a heavy ion accelerator.

Isotopes: Oganesson has one isotope whose half-life is known very approximately: 294Og, with a half-life of 0.89 milliseconds.


1. Oganessian et al., Results of the first 249Cf + 48Ca Experiment. (pdf download)
2. Photo: ORNL

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