Fermium

Metal

synthetic

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

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Er

Es				Md

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Physical data

Electronic 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: --

Thermal data

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

Steric data

Atomic radius: -- Å
Ionic radius: -- Å
Covalent radius: -- Å
Atomic volume: -- cm³/mol
Density (293 K): -- g/cm³
Crystal structure: --

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Isotopes

Nuclide	Mass	Spin	Halflife	Decay mode	Decay tree
²⁴⁹Fm	249	7/2	3m	EC, α	View
²⁵⁰Fm	250.08	0	30m	α, EC, SF	View
²⁵¹Fm	251	9/2	5.3h	EC, α	View
²⁵²Fm	252.083	0	1.058d	α, SF	View
²⁵³Fm	253.085	1/2	3d	EC, α	View
²⁵⁴Fm	254.087	0	3.24h	α, SF	View
²⁵⁵Fm	255.09	7/2	20.1h	α, SF	View
²⁵⁶Fm	256.092	0	2.63h	SF, α	View
²⁵⁷Fm	257.095	9/2	100.5d	α, SF	View

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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.

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