Quick Fact
Oganesson (Og), element 118, is the heaviest known element, with a half-life of just 0.7 milliseconds and a mass number of 294. Discovered in 2002 at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, it has no stable isotopes and no practical uses outside scientific research.
Where does oganesson come from?
Oganesson doesn’t exist naturally—it’s manufactured in particle accelerators by smashing heavy ions together. The actual experiments that produced it took place at Russia’s Flerov Laboratory of Nuclear Reactions, part of JINR in Dubna. Picture a high-tech forge where atoms are hammered into existence rather than swords, and you’ve got the right idea. No physical deposit of oganesson exists anywhere—just the lab where it was created.
What are the basic facts about oganesson?
| Property |
Value (as of 2026) |
Status |
| Atomic number |
118 |
Highest confirmed |
| Symbol |
Og |
IUPAC-approved since 2016 |
| Discovery year |
2002 |
First atom detected |
| Half-life |
~0.7 milliseconds |
Unstable; decays into livermorium |
| Synthesized atoms |
5 confirmed (as of 2026) |
All in Dubna experiments |
| Group |
Noble gas (predicted) |
May behave like a semiconductor |
| Uses |
None |
Purely experimental |
Why is oganesson so unusual?
Oganesson breaks a lot of rules you’d expect from a noble gas. First, it’s named after Yuri Oganessian, a legend in superheavy element research. More importantly, it’s predicted to be a solid at room temperature—something no other noble gas does. Back in 1999, Robert Smolańczuk’s early theoretical work suggested this element might exist, but actually making it required slamming calcium-48 ions into californium-249. The fact that it vanishes in less than a blink shows just how extreme the periodic table gets at the very end. It’s also the first noble gas to ignore the usual "octet rule," which hints that chemistry itself might act differently for elements this massive.
Can you visit where oganesson was discovered?
You won’t find any oganesson sitting around in Dubna—it’s long gone by the time scientists detect it. That said, you can tour the lab where it was made. JINR offers guided tours (in Russian and English) that take you to the U400 cyclotron, the machine responsible for its creation. While you’re in town, the Dubna Science Museum has exhibits on nuclear physics that might interest you. If you’re really into superheavy elements, keep an eye on Science and Nature—they regularly cover attempts to create element 120. For now, oganesson stays in the lab, proving you can "find" the heaviest elements without ever leaving your chair.
