61 Pm 145
Promethium
Lanthanide
Promethium (Pm) is a chemical element with atomic number 61, classified as a lanthanide. At room temperature it is a solid. It was discovered in 1945 by Charles D. Coryell et al..
Properties
- Atomic number
- 61
- Atomic mass
- 145 u
- Category
- Lanthanide
- Group
- 0
- Period
- 6
- Block
- f-block
- Electron configuration
- [Xe] 4f⁵ 6s²
- Phase at STP
- Solid
- Density
- 7.26 g/cm³
- Melting point
- 1315 K (1041.8 °C)
- Boiling point
- 3273 K (2999.8 °C)
- Electronegativity
- 1.13
- Atomic radius
- 205 pm
- Ionization energy
- 5.582 eV
- Discovery
- 1945 · Charles D. Coryell et al.
Common uses
Nuclear batteries, luminous paint, research
Did you know?
Only radioactive rare earth element and doesn't occur naturally on Earth.
Experiment with the elements
Promethium doesn't form any compounds in our lab yet, but the periodic table sandbox lets you combine dozens of other real elements into real compounds — water, table salt, ammonia and many more — with their true chemical formulas.