Meitnerium · element 109
The only element named solely after a woman, honouring the physicist who explained fission and never got a Nobel
Key facts
On 29 August 1982 a single atom of element 109 appeared in a detector at GSI in Darmstadt, lived for a few milliseconds, and decayed. That one atom was enough. Meitnerium had been found, and it would be named for Lise Meitner, the Austrian physicist who worked out the physics of nuclear fission in 1939 and was passed over for the Nobel Prize awarded to her collaborator Otto Hahn.
Curium honours Marie and Pierre Curie together. Meitnerium is the only element named after a real woman on her own. It sits in group 9 below iridium, and so little of it has ever existed that not a single chemistry experiment has yet been performed on it.
Where it is found
Meitnerium does not exist in nature and cannot be found by looking. Its longest-lived isotopes survive for a few seconds, so any atom formed in a stellar explosion would have decayed almost instantly. Every meitnerium atom ever detected was made in a laboratory, and the total is tiny, probably a few dozen atoms in over forty years.
The discovery reaction fired iron-58 nuclei at bismuth-209, a cold fusion approach where the projectile has just enough energy to merge with the target. The yield is extraordinarily low, which is why the first run produced one atom. Today most meitnerium atoms appear briefly in the decay chains of nihonium and moscovium, which are made by hitting americium-243 with calcium-48 at Dubna.
How it was discovered
Peter Armbruster and Gottfried Munzenberg at GSI had already used their SHIP velocity filter to find bohrium in 1981. Element 109 came next. In August 1982 they caught a single meitnerium-266 nucleus, identified not by seeing the atom but by its signature: an alpha particle of the right energy, followed by decays to known isotopes of bohrium and lawrencium. Later experiments from 1988 onwards added more atoms.
GSI proposed the name meitnerium in 1992 and, unusually for that decade, nobody argued. IUPAC approved it in 1997. Meitner, who was Jewish, fled Germany in 1938 and kept corresponding with Hahn from Sweden. When Hahn and Fritz Strassmann found barium in neutron-bombarded uranium, it was Meitner and her nephew Otto Frisch who explained that the nucleus had split, and who coined the word fission. She died in 1968.
What we use it for
There are no uses for meitnerium and none are expected. Its half-lives are too short and its production rate too low even for the sort of one-atom-at-a-time chemistry that has been done on hassium and seaborgium.
Scientists still care about it for two reasons. First, its isotopes are stepping stones. When a moscovium nucleus decays through nihonium, roentgenium and meitnerium on its way to dubnium, each step confirms the identity of those above. Second, meitnerium is a test case for theory. Calculations suggest it should behave like a heavy iridium, favouring a +3 oxidation state and perhaps reaching very high states as iridium can. Whether relativity bends those predictions is a question a future, longer-lived isotope might let chemists answer.
Reading the numbers
Every physical value shown for meitnerium is a calculation or a placeholder. The atomic mass of 278 is the longest-lived isotope known, which survives for a few seconds. The predicted density of about 37 grams per cubic centimetre would make it one of the densest substances imaginable, but there has never been a visible sample to weigh. Melting point, boiling point, electronegativity and ionisation energies are all unknown.
The predicted configuration [Rn] 5f14 6d7 7s2 gives nine electrons outside the radon core, placing meitnerium in group 9 with cobalt, rhodium and iridium. Iridium is famously unreactive, and meitnerium is expected to be a noble metal too. Nothing has yet contradicted this, mostly because nothing has yet been tested. Meitnerium is one of the few elements where the periodic table is still making a prediction that has never been checked.
Safety and the environment
Meitnerium is radioactive and short-lived, with half-lives from milliseconds to a few seconds. It cannot be stored, shipped or released. The few dozen atoms ever made were created inside shielded accelerator facilities and detected through their own decay. There is no meitnerium in the environment and no risk to the public.
Did you know?
- The 1982 discovery rested on a single atom, identified by the chain of alpha decays it produced in the detector.
- Lise Meitner was nominated for a Nobel Prize dozens of times in both physics and chemistry but never received one.
- Meitner became the first woman in Germany to hold the title of full professor of physics, at the University of Berlin in 1926.
- Her gravestone in Hampshire, England, carries an inscription written by her nephew Otto Frisch describing her as a physicist who never lost her humanity.
- Meitnerium was one of the few names in the 1990s element disputes that every laboratory accepted without objection.
More in the superheavy elements
The nearest neighbours of meitnerium in the family, by atomic number.
See all 15 superheavy elements on one page, or browse all 118 elements. Also listed under the transition metals.
Frequently asked questions
Who is meitnerium named after?
Lise Meitner, the Austrian-Swedish physicist who, with Otto Frisch, gave the first physical explanation of nuclear fission in 1939. She is the only woman to have an element named solely after her. Curium honours Marie Curie jointly with her husband Pierre.
How many atoms of meitnerium have been made?
Very few, probably only a few dozen in total since 1982. The first experiment produced a single atom, and later work has added small numbers, mostly as decay products of heavier elements.
What is the half-life of meitnerium?
The discovery isotope, meitnerium-266, lasted a few milliseconds. The longest-lived isotope known, meitnerium-278, survives for several seconds before decaying by alpha emission.
Why did Lise Meitner not win the Nobel Prize?
Otto Hahn alone received the 1944 Nobel Prize in Chemistry for discovering fission, even though Meitner had led the research programme and explained the physics. Historians attribute her omission to a mix of disciplinary bias, wartime politics and the difficulty the committee had in judging interdisciplinary work.
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Written by Anthony. Updated September 2026. Numerical data from Periodic-Table-JSON (CC BY-SA), cross-checked against the Meitnerium reference article. Spotted an error? Tell us.