Samarium (Sm)
Lanthanide
Samarium teams up with cobalt to form magnets that shrug off heat that would demagnetise neodymium magnets, keeping motors and sensors working in jet engines and downhole drills.
Position on the periodic table
Atomic properties
| Atomic number | 62 |
|---|---|
| Atomic mass | 150.362 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f6 |
| Noble gas shorthand | [Xe] 4f6 6s2 |
| Electrons per shell | 2, 8, 18, 24, 8, 2 |
| Valence electrons (outer shell) | 2 |
| Common oxidation states | +3, +2 |
| Electronegativity (Pauling) | 1.17 |
| Covalent radius (approx.) | 198 pm |
| First ionization energy | 544.5 kJ/mol |
| Electron affinity | 15.6 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 7.52 g/cm³ |
| Melting point | 1071.8 °C (1345 K) |
| Boiling point | 1899.8 °C (2173 K) |
| Appearance | silvery white |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of samarium
Samarium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f6, usually shortened to [Xe] 4f6 6s2. Its electrons occupy 6 shells (2, 8, 18, 24, 8, 2), placing it in period 6 of the f-block. Explore it interactively in the electron configuration calculator.
Uses of samarium
- Heat-resistant SmCo magnets
- Cancer therapy isotope (Sm-153)
- Reactor control rods
- Specialist catalysts
Biological role: None known.
Occurrence: Extracted from monazite and bastnäsite.
Common compounds of samarium
Sm2O3
Samarium(III) oxide
History and discovery
Discovered: 1879 — Lecoq de Boisbaudran. Name origin: From the mineral samarskite, itself named after Russian mining engineer Vasili Samarsky.
Paul-Émile Lecoq de Boisbaudran isolated samarium from samarskite in 1879.
Safety notes
Low toxicity; standard rare-earth handling precautions.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Samarium
1. What is the chemical symbol of Samarium?
2. What is the atomic number of Samarium?
3. Which category does Samarium belong to?
4. What is the state of Samarium at room temperature?
5. Which period of the periodic table is Samarium in?
Samarium FAQs
What is the atomic number of samarium?
Samarium's atomic number is 62 — every samarium atom has 62 protons in its nucleus.
What is the symbol for samarium?
Sm. From the mineral samarskite, itself named after Russian mining engineer Vasili Samarsky.
Is samarium a metal, nonmetal, or metalloid?
Samarium is classified as a lanthanide.
What state is samarium at room temperature?
At about 25 °C, samarium is a solid. It melts at 1071.8 °C.
What is samarium used for?
Key uses include: heat-resistant smco magnets; cancer therapy isotope (sm-153); reactor control rods.
Related elements
Keep working with this element
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