About

Samarium is a silvery-white rare-earth metal that is stable in air. It is used to create powerful samarium-cobalt magnets, which are notable for their ability to retain their magnetism at very high temperatures (up to 700°C). This makes them highly useful in demanding military, aerospace, and high-performance motor applications where heat resistance is critical.

Atomic Properties

Atomic Number62

Atomic Weight150.36 u

Neutrons (common)90

Electron Configuration[Xe] 4f⁶ 6s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f⁶ 5s² 5p⁶ 6s²

Electrons per Shell2, 8, 18, 24, 8, 2

Electronegativity1.17

Electron Affinity15.63 kJ/mol

Oxidation States+3, +2

Covalent Radius166 pm

Ionic Radius95.8 pm

Periodic Table Position

Group3

Period6

BlockF

Chemical SeriesLanthanoids

Physical Properties

State at STPsolid

AppearanceSilvery white metallic

Crystal Structurerhombohedral

Magnetic Orderingantiferromagnetic

Speed of Sound2,130 m/s

Poisson Ratio0.274

Thermal Properties

Melting Point1,345 K

Boiling Point2,076 K

Thermal Expansion0 1/K

Thermal Conductivity13.3 W/(m·K)

Specific Heat0.197 J/(g·K)

Molar Heat29.62 J/(mol·K)

Heat of Fusion8.62 kJ/mol

Heat of Vaporization165 kJ/mol

Abundance

In Earth's Crust7.05 ppm

In Ocean0 ppm

In Solar System0.198 ppm

In Universe0.005 ppm

Discovery

Discovered byLecoq de Boisbaudran

Discovery Year1,879

Occurrenceprimordial

CAS Number7440-19-9

Electron Configuration

Energy

↿⇂

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Isotopes of Samarium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
¹⁴⁴Sm	143.912000	3.08%	Stable	Stable
¹⁴⁷Sm	146.914890	15%	106.6 Gy	Alpha Decay
¹⁴⁸Sm	147.914820	11.25%	6.3 Py	Alpha Decay
¹⁴⁹Sm	148.917180	13.82%	Stable	Stable
¹⁵⁰Sm	149.917270	7.37%	Stable	Stable
¹⁵²Sm	151.919730	26.74%	Stable	Stable
¹⁵⁴Sm	153.922210	22.74%	Stable	Stable

Interactive Visualization

Explore the 3D Bohr model of Samarium in our interactive viewer.

View 3D Model of Samarium