ElementsWhat is samarium?
Samarium is a silvery metal of the lanthanide row.
What is samarium used for?
Samarium-cobalt magnets that keep working at high temperatures, control rods in nuclear reactors, and lasers.
Where the name comes from
From samarskite, a mineral named after a Russian mining officer, Samarsky-Bykhovets.
Key facts
- Symbol
- Sm
- Atomic number
- 62
- Atomic mass
- 150.4 u
- Family
- Lanthanide
- Period
- 6
- Group
- none (f-block)
- Block
- f
- State at room temperature
- Solid
- Melting point
- 1,074 °C (1,347 K, 1,965 °F)
- Boiling point
- 1,794 °C (2,067 K, 3,261 °F)
- Density
- 7.52 g/cm³
- Electrons per shell
- 2, 8, 18, 24, 8, 2
- Electron configuration
- [Xe]6s2 4f6
- Common oxidation states
- +3, +2
- Electronegativity (Pauling)
- 1.17
- First ionisation energy
- 5.644 eV
- Electron affinity
- no value
- Atomic radius (van der Waals)
- 229 pm
- Discovered
- 1879
Place in the periodic table
Samarium is element number 62. It sits in period 6 (row 6) of the periodic table, in the separate row of lanthanides drawn below the main table, and belongs to the f-block. Just before it comes promethium (61), and just after it comes europium (63).
Family: Lanthanides.
Physical properties
At room temperature samarium is a solid. It melts at 1,074 °C and boils at 1,794 °C, so it stays liquid over a range of 720 degrees. Its density is 7.52 grams per cubic centimetre, so a one-litre block would weigh about 7.52 kilograms. By density it ranks 42nd among the 96 elements with a measured value.
Inside the atom
An atom of samarium has 62 protons in its nucleus and, when neutral, 62 electrons around it. The electrons are arranged in 6 shells: 2, 8, 18, 24, 8, 2. The outermost shell holds 2 electrons. Written in full, the electron configuration is [Xe]6s2 4f6.
Its electronegativity on the Pauling scale is 1.17. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 5.644 electronvolts (about 545 kilojoules per mole). One mole of samarium weighs 150.4 grams, so a single gram contains about 4.00 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains samarium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.