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Promethium (Pm)
Atomic number 61 · Lanthanide
| Atomic number | 61 |
|---|---|
| Atomic mass | 144.91276 u |
| Molar mass | 144.91276 g/mol |
| Category | Lanthanide |
| Group / period / block | — / 6 / f |
| Electron configuration | [Xe] 4f5 6s2 |
| Electrons per shell | 2, 8, 18, 23, 8, 2 |
| Atomic radius | 185.0 pm |
| Density | 7.26 g/cm³ |
| First ionisation energy | 5.5819 eV |
| Melting point | 1315.15 K (1042.00 °C) |
| Common oxidation states | +3 |
Uses
Nuclear batteries, research (radioactive)
Discovery
1945, J.A. Marinsky, L.E. Glendenin, C.D. Coryell