Lanthanum (La) is a lanthanide element belonging to the rare-earth metals, with atomic number 57 and atomic mass 138.90547 u. This sheet describes its fundamental properties, periodic position and physical characteristics.
Identity
- Name: Lanthanum
- Symbol: La
- Atomic number: 57
- Atomic mass: 138.90547 u
Position in the periodic table
- Series: Lanthanide
- Period: 6
- Category: Rare-earth metal
Physico-chemical properties
- Standard state: Solid
- Melting point: ~920 °C
- Density: ~6.15 g/cm³
- Electron configuration: [Xe] 5d¹ 6s²
Scientific description
Lanthanum is a chemical element with symbol La and atomic number 57. It belongs to the lanthanide series, part of the rare-earth metals, and is located in period 6. Its standard atomic mass is 138.90547 u.