0.7 ms α Standard atomic weight (Ar) (294) | 11.65±0.06 Lv | |
Oganesson (118Og) is a synthetic element created in particle accelerators, and thus a standard atomic mass cannot be given. Like all synthetic elements, it has no stable isotopes. The first (and so far only) isotope to be synthesized was 294Og in 2006; it has a half-life of 7 milliseconds.
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Notes
Theoretical
Theoretical calculations done on the synthetic pathways for, and the half-life of, other isotopes have shown that some could be slightly more stable than the synthesized isotope 294Og, most likely 293Og, 295Og, 296Og, 297Og, 298Og, 300Og and 302Og. Of these, 297Og, might provide the best chances for obtaining longer-lived nuclei, and thus might become the focus of future work with this element. Some isotopes with many more neutrons, such as some located around 313Og, could also provide longer-lived nuclei.
Target-projectile combinations leading to Z=118 compound nuclei
The below table contains various combinations of targets and projectiles that could be used to form compound nuclei with Z=118.
Theoretical calculations on evaporation cross sections
The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.
DNS = Di-nuclear system ; σ = cross section