Samarium

Metal

Symbol: Sm
Atomic number: 62
Atomic mass: 150.36
Group: Lanthanide
CAS-number: 7440-19-9

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Physical data

Electronic data

Shells: 2, 8, 18, 24, 8, 2
Orbitals: [Xe] 4f⁶ 6s²
Electronegativity: --, 1.1
1. Ionization potential: 5.6437 eV
2. Ionization potential: 11.069 eV
3. Ionization potential: 23.423 eV
Oxidation states: 3, 2
Electrical conductivity: 0.00956 10^6

Thermal data

Melting point: 1074 °C
Boiling point: 1794 °C
Specific heat: 0.20 J/gK
Heat of fusion: 8.630 kJ/mol
Heat of vaporization: 166.40 kJ/mol
Thermal conductivity: 0.133 W/cmK

Steric data

Atomic radius: 2.59 Å
Ionic radius: 1.08 Å (+3)
Covalent radius: 1.62 Å
Atomic volume: 19.95 cm³/mol
Density (293 K): 7.54 g/cm³
Crystal structure: rhombohedral

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Isotopes

Nuclide	Abundance [%]	Mass	Spin	Halflife	Decay mode	Decay tree
¹⁴⁴Sm	3.09	143.912	0	--	--
¹⁴⁵Sm	0	145	7/2	340d	EC	View
¹⁴⁶Sm	0	145.913	0	1.03E08y	α	View
¹⁴⁷Sm	14.97	146.915	7/2	1.06E11y	α	View
¹⁴⁸Sm	11.24	147.915	0	7E15y	α	View
¹⁴⁹Sm	13.83	148.917	7/2	--	--
¹⁵⁰Sm	7.44	149.917	0	--	--
¹⁵¹Sm	0	151	5/2	90.0y	β-	View
¹⁵²Sm	76.72	151.92	0	--	--
¹⁵³Sm	0	153	3/2	1.929d	β-	View
¹⁵⁴Sm	22.71	153.922	0	--	--

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Other info

Name origin:	Named after the mineral samarskite.
Description:	Silvery rare earth metal.
Discovered by:	Paul émile Lecoq de Boisbaudran
Year:	1879
Place:	France
Sources:	Found with other rare earths in monazite sand. The sand is often 50% rare earths by mass and 2.8% samarium.
Use(s):	It is used in the electronics and ceramics industries. It is easily magnetized and very difficult to demagnetize. This suggests important future applications in solid-state and superconductor technologies.

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