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.
Experiment with the elements
Lutetium 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.