Promethium
Promethium (钷, symbol Pm) is chemical element number 61, a Lanthanide in period 6 of the periodic table, with a standard atomic weight of about 145. Only radioactive lanthanide. Used in luminous paint and nuclear-powered devices.
Properties
| Atomic number | 61 |
|---|---|
| Symbol | Pm |
| Atomic mass | 145 u |
| Category | Lanthanide |
| Period | 6 |
| Group | — |
| Electron configuration | [Xe] 4f⁵ 6s² |
| Electronegativity | 1.13 |
| Covalent radius | 199 pm |
| Density | 7.26 g/cm³ |
| Melting point | 1315 K |
| Boiling point | 3273 K |
| Discovery | Marinsky, Glendenin, Coryell, 1945 |
Overview
Only radioactive lanthanide. Used in luminous paint and nuclear-powered devices. Element 61, Promethium (Pm), is a Lanthanide found in period 6. As a lanthanide (rare-earth) element it closely resembles its neighbours and serves in magnets, phosphors and catalysts.
With 2 electrons in its outermost shell, Promethium bonds accordingly; full configuration [Xe] 4f⁵ 6s², electronegativity 1.13. At room temperature it is normally a solid; it melts near 1315 K (1041.9 °C), boils near 3273 K (2999.9 °C), has a density around 7.26 g/cm³.
Common applications range across Energy / Batteries and Research. On the safety side, it carries a high hazard rating. It was first described by Marinsky, Glendenin, Coryell in 1945.
Electron shells
Electrons per shell: 2 · 8 · 18 · 23 · 8 · 2
Main uses
- Energy / Batteries
- Research
Hazard
Compounds containing Promethium
No compounds in this knowledge base contain Promethium yet.
Data sources
Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.