Periodic Table of Elements




Erbium was discovered by the Swedish chemist, Carl Gustaf Mosander in 1843.

Name: Erbium
Symbol: Er
Atomic number: 68
Atomic weight: 167.26
State: solid
Group, period, block: n/a, 6, f
Color: silvery white
Classification: lanthanide
Electron configuration: 4f12 6s2

Physical properties

Density: 9.066 g/cm-3
Melting point: 1802 K,1529 C,2784 F
Boiling point: 3141 K,2868 C,5194 F

Atomic properties

Oxidation states: 3, 2, 1
Electronegativity: 1.24 (Pauling scale)
Ionization energies: 1st: 589.3 kJmol-1
Covalent radius: 1896 pm
Van der Waals radius: no data
  • Er
  • Electron Configuration


There are six naturally occurring isotopes of erbium exist, 162Er, 164Er, 166Er, 167Er, 168Er, and 170Er. About 33.503% of the erbium in nature is 166Er.