71 Lu 174.97
Lutetium
Lanthanide
Lutetium (Lu) is a chemical element with atomic number 71, classified as a lanthanide. At room temperature it is a solid. It was discovered in 1907 by Carl Auer von Welsbach, Georges Urbain.
Properties
- Atomic number
- 71
- Atomic mass
- 174.97 u
- Category
- Lanthanide
- Group
- 3
- Period
- 6
- Block
- d-block
- Electron configuration
- [Xe] 4f¹⁴ 5d¹ 6s²
- Phase at STP
- Solid
- Density
- 9.84 g/cm³
- Melting point
- 1925 K (1651.8 °C)
- Boiling point
- 3675 K (3401.8 °C)
- Electronegativity
- 1.27
- Atomic radius
- 217 pm
- Ionization energy
- 5.426 eV
- Discovery
- 1907 · Carl Auer von Welsbach, Georges Urbain
Common uses
Medical imaging, catalysts, research, dating meteorites
Did you know?
Most expensive of all rare earth elements and very hard to extract.