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.
Experiment with the elements
Lanthanum 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.