Samarium (Sm)
Samarium (Sm) is element 62, a lanthanide. Atomic mass 150.36, configuration [Xe] 4f⁶ 6s². Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 62 |
|---|---|
| Symbol | Sm |
| Standard atomic weight | 150.36(2) |
| Category | Lanthanide |
| Period | 6 |
| State at room temperature | Solid |
| Electron configuration | [Xe] 4f⁶ 6s² |
| Valence electrons | 2 (Variable) |
| Common oxidation states | +3 |
| Common ions | No common ions |
| Electronegativity (Pauling) | 1.17 |
| First ionization energy | 545 kJ/mol |
| Atomic radius | 185 pm |
| Density | 7.52 g/cm³ |
| Melting point | 1073°C |
| Boiling point | 1794°C |
| Specific heat | 0.196 J/(g·°C) |
Natural isotopes
- Sm-144: Stable
- Sm-147: Radioactive
- Sm-149: Stable
- Sm-150: Stable
- Sm-152: Stable
- Sm-154: Stable
Common uses
- Samarium-Cobalt magnets (high temp stability)
- Cancer treatment (Sm-153)
Where it matters
- Magnet Technology (SmCo magnets)
Hazards
- Low toxicity
History
| Discovered | 1879 |
|---|---|
| Discovered by | Lecoq de Boisbaudran |
| Name | From Mineral Samarskite |