Praseodymium (Pr)
Praseodymium is the chemical element with atomic number 59 and symbol Pr. It is a lanthanoid in period 6, with a standard atomic weight of 140.91 u.
Key facts
- Z
- 59
- Atomic weight
- 140.91 u
- Category
- lanthanoid
- State at 298 K
- Solid
- Occurrence
- primordial
- Discovered
- 1841
- CAS
- 7440-10-0
Measured properties
| Property | Value | Source |
|---|---|---|
| Electronegativity | 1.13 | National Center for Biotechnology Information (NIH) |
| Melting point | 1,204 K | National Center for Biotechnology Information (NIH) |
| Boiling point | 3,793 K | National Center for Biotechnology Information (NIH) |
| Density stp | 6.77 g/cm³ | National Center for Biotechnology Information (NIH) |
| Atomic radius empirical | 239 pm | National Center for Biotechnology Information (NIH) |
| Ionization energy 1st | 527.2 kJ/mol | National Center for Biotechnology Information (NIH) |
Electron configuration
- Noble gas notation
- [Xe] 4f³ 6s²
- Full notation
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f³ 5s² 5p⁶ 6s²
- Electrons per shell
- 2, 8, 18, 21, 8, 2