57 La 138.91
Lanthanum
Lanthanide
Lanthanum (La) is a chemical element with atomic number 57, classified as a lanthanide. At room temperature it is a solid. It was discovered in 1839 by Carl Gustaf Mosander.
Properties
- Atomic number
- 57
- Atomic mass
- 138.91 u
- Category
- Lanthanide
- Group
- 3
- Period
- 6
- Block
- f-block
- Electron configuration
- [Xe] 5d¹ 6s²
- Phase at STP
- Solid
- Density
- 6.145 g/cm³
- Melting point
- 1193 K (919.9 °C)
- Boiling point
- 3737 K (3463.8 °C)
- Electronegativity
- 1.1
- Atomic radius
- 226 pm
- Ionization energy
- 5.577 eV
- Discovery
- 1839 · Carl Gustaf Mosander
Common uses
Camera lenses, catalysts, batteries, studio lighting
Did you know?
First of the lanthanides and essential for high-quality camera lenses.