Promethium (Pm)
Promethium (Pm) is element 61, a lanthanide. Atomic mass 145, configuration [Xe] 4f⁵ 6s². Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 61 |
|---|---|
| Symbol | Pm |
| Standard atomic weight | 145 |
| Category | Lanthanide |
| Period | 6 |
| State at room temperature | Solid |
| Electron configuration | [Xe] 4f⁵ 6s² |
| Valence electrons | 2 (Variable) |
| Common oxidation states | +3 |
| Common ions | No common ions |
| First ionization energy | 540 kJ/mol |
| Atomic radius | 185 pm |
| Density | 7.26 g/cm³ |
| Melting point | 1042°C |
| Boiling point | 3000°C |
Common uses
- Nuclear batteries for guided missiles/pacemakers
- Luminous paint
Where it matters
- Nuclear Batteries (Betavoltaics)
Hazards
- Radioactive
History
| Discovered | 1945 |
|---|---|
| Discovered by | Marinsky, Glendenin, Coryell |
| Name | From Prometheus (Greek titan who stole fire) |