Notation. Nuclides are written with the mass number as a left superscript (e.g., ²⁹⁴Og).
Columns. Stable? — Oganesson has no stable isotopes. Half-lives = evaluated values. Decay → daughter(s) shows main branches. Radiation: α, SF (spontaneous fission). Origin: all isotopes are synthetic. Uses: R research only.
Primary data spine: evaluated Isotopes of oganesson (ENSDF/NUBASE 2020).
Table — ground states
| Nuclide | Z | A | Stable? | Half-life | Decay → daughter(s) | Radiation | Origin | Notes & Uses |
|---|---|---|---|---|---|---|---|---|
| ²⁹³Og | 118 | 293 | No | ~0.9 ms | α → ²⁸⁹Lv | α | Fusion-evap. | R. |
| ²⁹⁴Og | 118 | 294 | No | ~0.7 ms | α → ²⁹⁰Lv; SF | α; SF | Synthetic (Dubna–LLNL collab.) | First confirmed isotope; discovery isotope of Og. |
Natural isotopes of oganesson
- None.
- All isotopes are synthetic, produced in 2002 and 2006 at the Joint Institute for Nuclear Research (Dubna, Russia) in collaboration with Lawrence Livermore National Laboratory (LLNL, USA).
- Reaction used: Calcium-48 + Californium-249 → Oganesson isotopes.
- IUPAC recognized Oganesson as element 118 in 2016, named in honor of Russian physicist Yuri Oganessian.
Applied & research highlights
- ²⁹⁴Og (~0.7 ms): the first confirmed isotope, established the existence of element 118.
- Oganesson is in Group 18 (noble gases), but theoretical predictions suggest it is not inert like helium, neon, or argon.
- Relativistic effects likely make it a semiconductor or weakly metallic solid at room temperature, unlike lighter noble gases.
- It may even form compounds more readily than radon.
- No applications — only research interest; only a few atoms have ever been synthesized.
Totals — Oganesson (Z = 118)
- Ground-state isotopes listed2 (A = 293–294).
- Stable0.
- Unstable2.
Running cumulative totals (through Og):
From Ts ledger: ≥ 3 352 total, 252 stable, ≥ 3 099 unstable.
Add Og (+2 total, +0 stable, +2 unstable) → ≥ 3 354 total, 252 stable, ≥ 3 101 unstable.
Sources
- Isotopic list (A = 293–294)Isotopes of oganesson (ENSDF/NUBASE 2020).
- Discovery (Dubna–LLNL, 2002–2006)Ca-48 + Cf-249 fusion.
- Naming (2016)IUPAC approval honoring Yuri Oganessian.
- Theoretical studiesrelativistic quantum chemistry predicting Og may be metallic and reactive.
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