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On 28 November 2016, the International Union of Pure and Applied Chemistry (IUPAC) approved names for four new elements, completing the seventh row of the periodic table for the first time. Every one of them has been made only a few atoms at a time, and every one of those atoms decayed within seconds or less.
The four newest elements
| Number | Name | Symbol | Named after | Discovered by |
|---|---|---|---|---|
| 113 | Nihonium | Nh | Japan (Nihon) | RIKEN, Japan |
| 115 | Moscovium | Mc | Moscow region | JINR (Dubna, Russia) with US partners |
| 117 | Tennessine | Ts | Tennessee, USA | JINR with Oak Ridge, Vanderbilt and Lawrence Livermore |
| 118 | Oganesson | Og | Yuri Oganessian | JINR with Lawrence Livermore |
Before 2016 they went by placeholder names built from Latin and Greek numbers: ununtrium, ununpentium, ununseptium and ununoctium (“one-one-three”, and so on).
Nihonium (113): the first element named in Asia
Nihonium was created at the RIKEN Nishina Center in Japan by firing zinc-70 nuclei at a bismuth-209 target (30 + 83 = 113 protons). The team, led by Kosuke Morita, spent roughly nine years of beam time and saw just three atoms — in 2004, 2005 and 2012 — before IUPAC credited them with the discovery. It’s the first element discovered in an Asian country.
Moscovium (115) and tennessine (117)
Both were made at the Joint Institute for Nuclear Research (JINR) in Dubna, near Moscow, using beams of calcium-48 — an unusually neutron-rich isotope, which helps produce heavier, slightly longer-lived superheavy nuclei.
- Moscovium: calcium-48 fired at americium-243 (20 + 95 = 115).
- Tennessine: calcium-48 fired at berkelium-249 (20 + 97 = 117). The berkelium target was made at Oak Ridge National Laboratory in Tennessee — about 22 milligrams of it, produced over months in a high-flux reactor and flown to Russia. Its short half-life (about 330 days) meant the whole experiment was a race against the clock.
Tennessine falls in group 17, the halogen column, which is why its name ends in “-ine” like chlorine and iodine.
Oganesson (118): the heaviest known element
Oganesson was made by firing calcium-48 at californium-249 (20 + 98 = 118). It’s named after Yuri Oganessian, the Russian-Armenian physicist who led much of the superheavy element research at Dubna — only the second element named after a living scientist, after seaborgium (for Glenn Seaborg).
It sits in group 18 with the noble gases, hence the “-on” ending shared by neon, argon, krypton, xenon and radon. But calculations suggest it may not behave like a noble gas at all: relativistic effects on its huge electron cloud may make it reactive, and possibly even a solid at room temperature. Nobody can check — too few atoms have existed. See the heaviest element.
How IUPAC decides
Claims of new elements are reviewed by a joint working party of IUPAC and IUPAP (the physics equivalent). They look for independent confirmation and a convincing chain of decays linking the new nucleus to known isotopes. Only then do the discoverers get to propose a name, which must follow set rules: elements can be named after a mythological concept, a mineral, a place or country, a property, or a scientist. The proposal goes out for public comment before final approval.
What’s next: elements 119 and 120
Making heavier elements gets harder with each step. The probability of two nuclei fusing and surviving drops dramatically, and the targets needed (like einsteinium or curium) are extremely scarce. Labs in Japan, Russia, the USA and China are attempting elements 119 and 120, often using beams of titanium-50 or chromium-54 instead of calcium-48. As of this writing, none has been confirmed.
Element 119 would start an eighth row of the periodic table, in group 1 below francium. Physicists also hope eventually to reach the predicted island of stability — superheavy nuclei that might last much longer than their neighbours.
Quick answers
What is the newest element? Elements 113, 115, 117 and 118 were all named together in 2016. By discovery date, tennessine (first made in 2010) is the most recent.
How many elements are there? 118 confirmed.
Can you see these elements? No. They’ve only been detected atom by atom, through the particles and energies given off as they decay.
Related
Learn how new elements are made, or see where these four sit in the seventh row of the periodic table.
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