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Meitnerium (Mt)
Meitnerium (symbol Mt) is the chemical element with atomic number 109: a superheavy element whose properties are still unknown, radioactive, made artificially, with an atomic mass of 278 u. Discovered in 1982 (Peter Armbruster and Gottfried Münzenberg (GSI)).
Meitnerium honors Lise Meitner, the Austrian physicist who explained nuclear fission but never received the Nobel Prize for that discovery. It was created at GSI in Darmstadt in 1982, from a single atom. Its most stable known isotope, meitnerium-278, lives a few seconds. Nothing is known about its chemistry.
Key facts
- Atomic number
- 109
- Symbol
- Mt
- French name
- Meitnérium
- Atomic mass
- 278 u
- Molar mass
- [278] g/mol
- Family
- Unknown properties
- Position
- period 7, group 9, d-block
- State at 0 °C
- Unknown
- First ionization energy
- 800 kJ/mol
- Electron configuration
- [Rn] 5f¹⁴ 6d⁷ 7s²
- Radioactive
- yes
- Discovery
- 1982, Peter Armbruster and Gottfried Münzenberg (GSI)
Origin of the name
In honor of the physicist Lise Meitner.
What does meitnerium look like?
Never observed; predicted to be a very dense metal.
Where is meitnerium found?
Absent from nature.
How is meitnerium produced?
GSI bombards a bismuth-209 target with accelerated iron-58 ions. The longest-lived isotopes show up in the decay chains of tennessine and moscovium.
Top producers
- Germany (GSI Darmstadt)
What is meitnerium used for?
- Basic research only
In everyday life
- None — it exists only for moments in the lab
Role in living things
No biological role.
Hazards of meitnerium
Radioactive, but produced atom by atom: no practical danger.
Cosmic origin
- Human-made: Does not exist (or barely) in nature: synthesized in a reactor or accelerator.
History of meitnerium
On August 29, 1982, Peter Armbruster and Gottfried Münzenberg's team at GSI observed a single atom of meitnerium-266 after days of continuous bombardment. The name, proposed as a tribute to Lise Meitner, became official in 1997.
Did you know?
- The element was claimed on the basis of a single atom, detected just once — a testament to the precision of modern detectors.
- Lise Meitner, who was of Jewish origin, had to flee Nazi Germany in 1938; it was from Sweden that she interpreted the fission discovered by her former colleague Otto Hahn, who alone received the Nobel.
- Curium also honors Marie Curie, but jointly with Pierre: meitnerium is the only one dedicated to a woman alone.
Isotopes of meitnerium
No stable isotopes; meitnerium has only ever been observed a few atoms at a time.
- meitnerium-266: radioactive, half-life 1.2 ms. The element's first synthesized isotope, in 1982: a single atom.
- meitnerium-278: radioactive, half-life 4.5 s. Among the longest-lived known, a decay product of tennessine.
Related elements
Same family (unknown properties): Darmstadtium (Ds), Roentgenium (Rg), Copernicium (Cn), Nihonium (Nh), Flerovium (Fl), Moscovium (Mc), Livermorium (Lv), Tennessine (Ts), Oganesson (Og).
Same column (group 9): Cobalt (Co), Rhodium (Rh), Iridium (Ir).