89 Ac 227
Actinium
Actinide
Actinium (Ac) is a chemical element with atomic number 89, classified as a actinide. At room temperature it is a solid. It was discovered in 1899 by André-Louis Debierne.
Properties
- Atomic number
- 89
- Atomic mass
- 227 u
- Category
- Actinide
- Group
- 3
- Period
- 7
- Block
- f-block
- Electron configuration
- [Rn] 6d¹ 7s²
- Phase at STP
- Solid
- Density
- 10.07 g/cm³
- Melting point
- 1323 K (1049.8 °C)
- Boiling point
- 3471 K (3197.8 °C)
- Electronegativity
- 1.1
- Atomic radius
- 260 pm
- Ionization energy
- 5.17 eV
- Discovery
- 1899 · André-Louis Debierne
Common uses
Cancer treatment, neutron sources, research
Did you know?
First of the actinides and glows blue in the dark.