Samarium
Element 62 · Lanthanide
Samarium is a fairly typical lanthanide in appearance — silvery, reasonably stable in air, usually +3 — but two applications make it special. Samarium-cobalt magnets keep their strength at temperatures that demagnetize ordinary magnets, so they work inside jet engines, precision motors, and high-temperature sensors.
In medicine, the isotope samarium-153 is used in targeted therapy that relieves pain from cancers spread to bone. Samarium also absorbs neutrons well, finding use in reactor control materials.
Key facts
| Atomic number | 62 |
|---|---|
| Atomic weight | 150.36 |
| Category | Lanthanide |
| Group / Period | — / 6 |
| Block | f |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f6 |
| Common oxidation states | +3, +2 |
| State at STP | Solid |
| Electronegativity | 1.17 |
| Density | 7.52 g/cm³ |
| Melting point | 1072 °C |
| Boiling point | 1794 °C |
Occurrence
Samarium is found in monazite and bastnasite, and is separated from the other lanthanides by ion exchange or solvent extraction.
Applications
Samarium-cobalt high-temperature magnets
Sm-153 therapy for bone cancer pain
Neutron-absorbing reactor materials
Precision motors and sensors
Common compounds
- samarium oxide
- samarium chloride
- samarium hexaboride
Samarium-cobalt magnets keep working at temperatures that would destroy ordinary magnets — which is why they fly inside jet engine sensors.
Data source: IUPAC standard atomic weights 2021