Oganesson
Oganesson is the heaviest element on the periodic table and closes Group 18 (the noble gases). Named after Yuri Oganessian, the leading researcher in superheavy element synthesis. Only 5 atoms have ever been confirmed. Due to relativistic effects it may actually be a solid at room temperature rather than a gas like all other noble gases.
- Atomic Number118118 protons, 118 electrons
- Atomic Mass295.216 uOver 118× heavier than hydrogen
- State at Room TempExpected to be a Gaspredicted solid
- DensityNot measuredPredicted from periodic trends
- Melting / BoilingNot yet measuredDecays in milliseconds to hours
- Discovered2006First produced 2006s
What is Oganesson?
Og-294 has a half-life of approx. 0.89 milliseconds, less than one thousandth of a second. First synthesised in 2002 at JINR Dubna by bombarding californium with calcium. Named after Yuri Oganessian while he was still alive, only the second element named after a living person (after seaborgium). Sits at the corner of the periodic table, completing Period 7.
With 118 protons, Oganesson sits in Group 18 of the periodic table, Period 7, in the superheavy transactinide region. Its properties are predicted largely from theory and from single-atom chemistry experiments, not from bulk measurements.
Where you find Oganesson
On Earth
Oganesson does not exist naturally. It is made only artificially in nuclear physics laboratories by firing beams of one heavy nucleus at another and watching for the rare collisions that fuse them together. The main laboratories capable of producing superheavy elements are JINR in Dubna (Russia), GSI in Darmstadt (Germany), RIKEN in Japan and Lawrence Livermore National Laboratory in California.
How we use Oganesson
Oganesson has no practical uses. Only a handful of atoms have ever been produced, each existing for a fraction of a second to a few minutes. Research focuses on understanding nuclear structure, testing theoretical models of the atom, and searching for the predicted "island of stability", a region of superheavy nuclei that may be significantly longer-lived than those currently known.
How it was discovered
Og-294 has a half-life of approx. 0.89 milliseconds, less than one thousandth of a second. First synthesised in 2002 at JINR Dubna by bombarding californium with calcium. Named after Yuri Oganessian while he was still alive, only the second element named after a living person (after seaborgium). Sits at the corner of the periodic table, completing Period 7.
Deeper dive: superheavy elements and the island of stability
Nuclear physicists predict that certain combinations of protons and neutrons, "magic numbers", create particularly stable nuclei. For superheavy elements, a theoretical "island of stability" is predicted around element 114 (flerovium) or beyond, where nuclei with the right magic number of neutrons might have half-lives of years or even longer rather than milliseconds. So far, the search continues. Elements 113-118 were all officially confirmed and named in 2016, completing Period 7 of the periodic table. Whether an eighth period of elements beyond oganesson (118) can ever be made and studied remains one of the great open questions in chemistry and nuclear physics.
Superheavy elements are made by accelerating beams of lighter nuclei (often calcium-48, because of its convenient doubly-magic structure) to high energies and firing them at heavy targets (lead, bismuth, uranium, curium, californium). Very rarely, two nuclei fuse instead of bouncing apart. The fusion product is detected by its characteristic radioactive decay chain, a signature sequence of alpha decays each producing a known element, counted backwards to identify the original product.
With oganesson, we reach the end of the known periodic table. The search for element 119 and beyond continues in laboratories worldwide.