Periodic Table of Elements

57

Lanthanum

138.91

Lanthanum was discovered by a Swedish chemist, Carl Gustaf Mosander in the mineral cerite, in 1839.

Name: Lanthanum
Symbol: La
Atomic number: 57
Atomic weight: 138.91
State: solid
Group, period, block: n/a, 6, f
Color: silvery white
Classification: lanthanide
Electron configuration: 5d1 6s2
2,8,18,18,9,2

Physical properties

Density: 6.162 g/cm-3
Melting point: 1193 K,920 C,1688 F
Boiling point: 3737 K,3464 C,6267 F

Atomic properties

Oxidation states: 3, 2
Electronegativity: 1.10 (Pauling scale)
Ionization energies: 1st: 538.1 kJmol-1
Covalent radius: 2078 pm
Van der Waals radius: no data
  • La
  • Electron Configuration

Isotopes

There are two naturally occurring isotopes of lanthanum exist, 138La, and 139La.