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Elkahia gemstone emblemElkahia GemstoneEST. 2026 · QATAR
109Mt277.154

Element record / Transition metal

Meitnerium

MetalPrimarily synthetic supply
Atomic number
109
Atomic mass (u)
277.154
Category
Transition metal
Standard state
Solid
Melting point
Not reported
Boiling point
Not reported
Density (g/cm³)
Not reported in this source
Electronegativity (Pauling)
Not reported in this source
Electron configuration
[Rn]7s2 5f14 6d7 (calculated)
Oxidation states
9, 8, 6, 4, 3, 1
Atomic radius (pm)
Not reported in this source
First ionization energy (eV)
Not reported in this source

Discovery & recognition

Discovery year / period (PubChem)
1982
Discovery credited to (RSC)
Peter Armbruster, Gottfried Münzenberg and colleagues
Date or period recorded by RSC
1982
Discovery place
GSI, Germany

An ancient date does not identify a first human discovery. Different references may date observation, isolation and formal recognition differently.

Natural occurrence & production

This transuranium element is primarily produced through nuclear reactions in reactors or particle accelerators. Some transuranium elements also occur naturally in extremely small traces; that is different from a mineable deposit.

“Fewer than 10 atoms of meitnerium have ever been made, and it will probably never be isolated in observable quantities.”

Royal Society of Chemistry · occurrence excerpt ↗

Continue the research

Reference values are not product specifications. Blank values have not been estimated. For superheavy elements, some properties and family assignments are theoretical or incompletely measured.

Reference snapshot: September 2026. Source dates and uncertainties are retained in the record.