Prométhéum (Pm)
Prométhéum is the chemical element with atomic number 61 and symbol Pm. It is a lanthanide in period 6, with a standard atomic weight of 145 u.
Faits essentiels
- Z
- 61
- Atomic weight
- 145 u no stable isotope
- Category
- lanthanide
- State at 298 K
- Solid
- Occurrence
- from decay, radioactive
- Discovered
- 1945
- CAS
- 7440-12-2
Propriétés mesurées
| Property | Value | Source |
|---|---|---|
| Melting point | 1,315 K | National Center for Biotechnology Information (NIH) |
| Boiling point | 3,273 K | National Center for Biotechnology Information (NIH) |
| Density stp | 7.26 g/cm³ | National Center for Biotechnology Information (NIH) |
| Atomic radius empirical | 236 pm | National Center for Biotechnology Information (NIH) |
| Ionization energy 1st | 535.5 kJ/mol | National Center for Biotechnology Information (NIH) |
Configuration électronique
- Noble gas notation
- [Xe] 4f⁵ 6s²
- Full notation
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f⁵ 5s² 5p⁶ 6s²
- Electrons per shell
- 2, 8, 18, 23, 8, 2