Meitnerium
Transition metal (predicted) · Period 7 · Group 9 · d-block
Lise Meitner's element, first seen as one atom in 1982
- Atomic mass
- 278 u
- State at 25 °C
- Solid
- Electronegativity
- —
- Melting point
- —
- Boiling point
- —
- Configuration
- *[Rn] 5f14 6d7 7s2
Nucleus drawn at reduced count for clarity. Drag to rotate.
Meitnerium, explained
Video lesson in production
Bhavya’s explainer for this element will play here.
Overview
Meitnerium sits in group 9 below cobalt, rhodium and iridium. With a predicted 7s2 6d7 configuration, it is expected to be a noble metal like iridium, with its most stable oxidation states predicted to be +3, +6 and perhaps +1, and relativistic calculations suggest its compounds would resemble those of iridium. None of this has been measured. No chemistry experiment on meitnerium has yet been carried out, because its isotopes decay too quickly and are made too rarely.
Everything known about meitnerium comes from nuclear physics. Its longest-lived known isotopes, such as meitnerium-278, last for several seconds and are seen only at the ends of decay chains starting from heavier elements like nihonium and tennessine. In that sense meitnerium shows how the superheavy region is mapped: by tracking each atom's chain of alpha decays and spontaneous fission back to nuclides whose properties are already known.
Discovery
Peter Armbruster and Gottfried Münzenberg's team at GSI made meitnerium on 29 August 1982 by bombarding bismuth-209 with iron-58. A single atom of meitnerium-266 was detected after a week of bombardment, and its decay chain was enough to identify it. The name, adopted in 1997, honors Lise Meitner, the Austrian-Swedish physicist who, with Otto Frisch, gave the first physical explanation of nuclear fission in 1939.
- Where it’s found
- Meitnerium does not occur in nature; it is made in accelerators or appears in the decay chains of heavier synthetic elements.
- What it’s used for
- Decay-chain identification
- Nuclear structure research
- Testing group 9 predictions
- Superheavy element mapping
- In living things
- Meitnerium has no biological role; it is radioactive and has only ever existed as individual atoms.
- Safety
- Radioactive and made only a handful of atoms ever; it decays within seconds.
How it compares
Where Meitnerium sits among all 118 elements on the trends that shape the table.
- ElectronegativityNo data
Not measured for this element
- Ionization energyNo data
Not measured for this element
- Atomic radiusNo data
Not measured for this element
- Electron affinityNo data
Not measured for this element
- Density37.4g/cm³
#2 of 114 elements with data · predicted
- Melting pointNo data
Not measured for this element
- Density
- 37.4 g/cm³
- Atomic radius
- —
- Covalent radius
- —
- Molar heat
- —
- Appearance
- —
- Discovered by
- Gesellschaft für Schwerionenforschung
Inside the atom
109 electrons arranged in 7 shells: 2 · 8 · 18 · 32 · 32 · 15 · 2.
Orbital diagram
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d7 · shorthand *[Rn] 5f14 6d7 7s2
- 1s2
- 2s2
- 2p6
- 3s2
- 3p6
- 4s2
- 3d10
- 4p6
- 5s2
- 4d10
- 5p6
- 6s2
- 4f14
- 5d10
- 6p6
- 7s2
- 5f14
- 6d7
Each box is an orbital holding up to two electrons of opposite spin. Highlighted subshells hold the valence electrons that decide how Meitnerium bonds.
Signature reactions
How the first atoms were made, and how they fall apart.
Nuclear · Cold fusion
GSI cold-fusion synthesis
Iron-58 fuses with bismuth-209 and the compound nucleus emits one neutron. The single atom was identified by its alpha decay to bohrium-262 and the subsequent decays down the chain.
Conditions: iron-58 beam on bismuth-209, GSI UNILAC, 1982
Nuclear · Alpha decay
Alpha decay of meitnerium-266
Meitnerium-266 emits an alpha particle to become bohrium-262, which GSI had identified a year earlier. Recognizing that known daughter made a single atom enough for a discovery claim.
Conditions: spontaneous, half-life about 1 millisecond
Where you’ll meet it
Lise Meitner
The physicist who explained nuclear fission is honored by element 109.
Photo: Wikimedia Commons
Otto Hahn
Meitner's longtime collaborator received the 1944 Nobel Prize in Chemistry for fission while she was overlooked.
Photo: Wikimedia Commons
Iridium
Iridium, directly above meitnerium in group 9, is the model for its predicted chemistry.
Photo: Wikimedia Commons
GSI Helmholtz Centre for Heavy Ion Research
GSI's SHIP separator caught the first meitnerium atom in 1982.
Photo: Wikimedia Commons
_(cropped).jpg){kind=link}
Research
No research on Meitnerium yet
When Bhavya publishes a project that studies Meitnerium, it will be linked here.