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Fermium

Metal radioactivesynthetic
Symbol: Fm
Atomic number: 100
Atomic mass: (257.0951)
Group: Actinide
CAS-number: 7440-72-4

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Physical data

Electronic dataThermal dataSteric data
Shells: 2, 8, 18, 32, 30, 8, 2
Orbitals: [Rn] 5f12 7s2
Electronegativity: --, 1.2
1. Ionization potential: 6.50 eV
2. Ionization potential: -- eV
3. Ionization potential: -- eV
Oxidation states: 3
Electrical conductivity: --
Melting point: -- °C
Boiling point: -- °C
Specific heat: -- J/gK
Heat of fusion: -- kJ/mol
Heat of vaporization: -- kJ/mol
Thermal conductivity: 0.1 W/cmK
Atomic radius: -- Å
Ionic radius: -- Å
Covalent radius: -- Å
Atomic volume: -- cm³/mol
Density (293 K): -- g/cm³
Crystal structure: --

Isotopes

NuclideAbundance [%]MassSpinHalflifeDecay modeDecay tree
249Fm 0 249 7/2 3m EC, α View
250Fm 0 250.08 0 30m α, EC, SF View
251Fm 0 251 9/2 5.3h EC, α View
252Fm 0 252.083 0 1.058d α, SF View
253Fm 0 253.085 1/2 3d EC, α View
254Fm 0 254.087 0 3.24h α, SF View
255Fm 0 255.09 7/2 20.1h α, SF View
256Fm 0 256.092 0 2.63h SF, α View
257Fm 0 257.095 9/2 100.5d α, SF View

Other info

Name origin:Named in honor of the scientist Enrico Fermi.
Description:Synthetic radioactive metal.
Discovered by:Argonne, Los Alamos, University of California
Year:1953
Place:United States
Sources:Produced by bombarding lighter transuranium elements with still lighter particles or by neutron capture.
Use(s):It has no significant commercial applications.