Periodic table › Oganesson
1. Identity and classification
Unknown (predicted to be a dense, polarizable semiconducting solid or volatile liquid/gas at room temperature due to strong relativistic effects)
- Name and symbol
- Oganesson (Oganesson) · Og
- Atomic number
- 118
- Relative atomic weight / mass number
- [294]
- Group · period · block
- 18 · 7 · p
- Category
- Unknown Properties
- State near room temperature
- Unknown
- Stable isotopes
- No stable isotopes
- CAS number
- 54144-19-3
Square brackets [A] indicate a representative isotope mass number, not an average atomic weight. Neutron counts differ between isotopes.
2. Atomic structure and electron configuration
- Protons · electrons in a neutral atom
- 118 · 118
- Neutrons in reference isotope
- 176 (294Og)
- Full electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d¹⁰ 7s² 7p⁶- Abbreviated configuration
[Rn]7s² 7p⁶ 5f¹⁴ 6d¹⁰ (predicted)- Electrons per shell
- 2, 8, 18, 32, 32, 18, 8
- Listed oxidation states
- +6, +4, +2, +1, 0, -1
- Electronegativity
- Not established
- First ionization energy
- Not established · Not established
- Electron affinity
- Not established
- Covalent radius
- 157 pm
- van der Waals radius
- Not established
Configurations of superheavy elements may include theoretical predictions. Different definitions of atomic radius are not interchangeable.
3. Physical and thermal properties
- Density
- Not established
- Melting point
- Not established
- Boiling point
- Not established
- Crystal structure
- Unknown / Predicted
- Specific heat
- Not established
- Thermal conductivity
- Not established
- Enthalpy of fusion
- Not established
- Enthalpy of vaporization
- Not established
- Magnetic ordering
- Unknown
- Mohs hardness
- Not established
- Speed of sound
- Not established
Density and structure depend on temperature, pressure and allotrope. 25°C is a room-temperature reference, not STP. Unestablished values are not zero.
4. Chemical behavior and compounds
Bulk reactions are not established; experiments involve small numbers of radioactive atoms.
Selected compounds: None experimentally isolated; relativistic calculations predict OgF₂ and OgF₄ stability
Reaction reference
Bulk reactions are not established; experiments involve small numbers of radioactive atoms.
Bulk reactions are not established; experiments involve small numbers of radioactive atoms.
5. Isotopes
| Isotope | Status | Natural abundance | Half-life |
|---|---|---|---|
| 294Og | Radioactive | — | 0.58 ms |
Half-life units: s seconds, m minutes, h hours, d days, Y years. A dash means no natural-abundance value is given, not zero. Listed records are selected ground states; metastable states are distinct.
6. Discovery and occurrence
- Discovery
- 2006 CE
- Scientists associated with discovery
- Joint Institute for Nuclear Research (Yuri Oganessian et al.) & LLNL
- Location
- Russia (Dubna) / USA
- Origin
- Synthetic
- Listed crustal abundance
- 0 ppm
Minerals and naming reference
None — exclusively synthesized atom-by-atom via heavy-ion fusion (²⁴⁹Cf + ⁴⁸Ca → ²⁹⁴Og + 3n)
Named in 2016 in honor of nuclear physicist Yuri Oganessian (born 1933) for his pioneering contributions to the discovery of superheavy elements
7. Applications
No commercial or everyday applications due to sub-millisecond half-life
Detailed applications by field
- everyday
- No commercial or everyday applications due to sub-millisecond half-life
- industry
- None — produced only in single-atom quantities in particle accelerators
- electronics
- None
- medicine
- None
- energy
- None
- aerospace
- None
- agriculture
- None
- science
- Fundamental nuclear physics research into the 'Island of Stability' and relativistic quantum mechanics of Period 7 p-block elements
8. Biological role and safety
Hazard depends on the isotope, chemical form, dose and exposure route.
Elemental substances, ions, compounds and radioisotopes can have different health effects. This is an educational reference; laboratory work requires the material safety data sheet and trained supervision.
Biological role reference
None; only a few atoms have ever been synthesized, decaying within milliseconds.