Samarium (Sm)
Lanthanide · f-block · period 6
Silvery-white, moderately hard metal that slowly oxidises in air.
Samarium (symbol Sm) is chemical element number 62, a lanthanide in the lanthanide series (f-block), period 6 of the periodic table. Its standard atomic weight is 150.36 and its electron configuration is [Xe] 4f6 6s2. At room temperature it is a solid. The first element named after a person — the mine official Vasili Samarsky-Bykhovets.
Properties
| Atomic number | 62 |
|---|---|
| Atomic mass | 150.36 |
| Category | Lanthanide |
| Block | f-block |
| Group · Period | f-block series · 6 |
| Electron configuration | [Xe] 4f6 6s2 |
| Electrons per shell | 2, 8, 18, 24, 8, 2 |
| State at 25 °C | solid |
| Melting point | 1345 K |
| Boiling point | 2173 K |
| Density | 7.52 g/cm³ |
| Electronegativity (Pauling) | 1.17 |
| Radioactive | No |
| Origin | primordial |
| Discovered | 1879 · Paul-Émile Lecoq de Boisbaudran |
Key facts about Samarium
- The first element named after a person — the mine official Vasili Samarsky-Bykhovets.
- Samarium-cobalt magnets keep working at high temperatures where neodymium magnets fail.
- Absorbs neutrons, helping to control nuclear reactors.
- A radioactive samarium drug relieves the pain of cancer that has spread to bone.
What Samarium is used for
High-temperature magnets, reactor control rods, cancer pain relief, catalysts, carbon-arc lighting.
Where it sits in the periodic table
Samarium is in the lanthanide series, period 6, of the f-block. Its electron configuration [Xe] 4f6 6s2 means its outermost shell holds 2 electrons, which is what places it here and explains much of its chemistry. See Samarium on the interactive table →
Samarium — frequently asked questions
What is Samarium used for?
High-temperature magnets, reactor control rods, cancer pain relief, catalysts, carbon-arc lighting.
Is Samarium radioactive?
No. Samarium has at least one stable isotope and is not radioactive.
What is the electron configuration of Samarium?
Samarium has the electron configuration [Xe] 4f6 6s2, which is 2, 8, 18, 24, 8, 2 electrons per shell.
What group and period is Samarium in?
Samarium is in the lanthanide series (f-block), period 6, in the f-block. Its outer shell holds 2 electrons.
Who discovered Samarium?
Samarium was discovered in 1879 by Paul-Émile Lecoq de Boisbaudran.