Lanthanum
Lanthanum (镧, symbol La) is chemical element number 57, a Lanthanide in period 6, group 3 of the periodic table, with a standard atomic weight of about 138.91. Soft, silvery-white rare earth metal. Used in carbon arc lamps and camera lenses.
Properties
| Atomic number | 57 |
|---|---|
| Symbol | La |
| Atomic mass | 138.91 u |
| Category | Lanthanide |
| Period | 6 |
| Group | 3 |
| Electron configuration | [Xe] 5d¹ 6s² |
| Electronegativity | 1.1 |
| Covalent radius | 207 pm |
| Density | 6.145 g/cm³ |
| Melting point | 1193 K |
| Boiling point | 3737 K |
| Discovery | Carl Gustaf Mosander, 1839 |
Overview
Soft, silvery-white rare earth metal. Used in carbon arc lamps and camera lenses. Element 57, Lanthanum (La), is a Lanthanide found in period 6, group 3. As a lanthanide (rare-earth) element it closely resembles its neighbours and serves in magnets, phosphors and catalysts.
It has the configuration [Xe] 5d¹ 6s² and an electronegativity near 1.1; its 2 outer-shell electrons drive its bonding. Under standard conditions it exists as a solid; it melts near 1193 K (919.9 °C), boils near 3737 K (3463.9 °C), has a density around 6.145 g/cm³.
It is widely used in Electronics / Semiconductors, Catalysis and Energy / Batteries. It was first described by Carl Gustaf Mosander in 1839. See more trends in the visualization center.
Electron shells
Electrons per shell: 2 · 8 · 18 · 18 · 9 · 2
Main uses
- Electronics / Semiconductors
- Catalysis
- Energy / Batteries
Hazard
Compounds containing Lanthanum
No compounds in this knowledge base contain Lanthanum yet.
Data sources
Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.