About

Erbium is a silvery-white solid rare-earth metal that is relatively stable in air. Its most important application is in erbium-doped fiber amplifiers (EDFAs), which are devices that boost the signal in long-distance fiber optic cables without needing to convert it to electricity. These amplifiers form the backbone of the internet and global telecommunications networks. It's also used to create pink-colored glass.

Atomic Properties

Atomic Number68

Atomic Weight167.259 u

Neutrons (common)98

Electron Configuration[Xe] 4f¹² 6s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹² 5s² 5p⁶ 6s²

Electrons per Shell2, 8, 18, 30, 8, 2

Electronegativity1.24

Electron Affinity30.1 kJ/mol

Oxidation States+3

Covalent Radius157 pm

Van der Waals Radius226 pm

Ionic Radius89 pm

Periodic Table Position

Group3

Period6

BlockF

Chemical SeriesLanthanoids

Physical Properties

State at STPsolid

Appearancesilvery white, with a pinkish tinge in its salts

Crystal Structurehcp

Magnetic Orderingparamagnetic

Speed of Sound2,830 m/s

Poisson Ratio0.238

Thermal Properties

Melting Point1,802 K

Boiling Point3,141 K

Triple Point1,802 K

Thermal Expansion0 1/K

Thermal Conductivity14.5 W/(m·K)

Specific Heat0.168 J/(g·K)

Molar Heat28.1 J/(mol·K)

Heat of Fusion19.9 kJ/mol

Heat of Vaporization280 kJ/mol

Abundance

In Earth's Crust3.5 ppm

In Ocean0 ppm

In Solar System0.001 ppm

In Universe0.002 ppm

Discovery

Discovered byCarl Gustaf Mosander

Discovery Year1,843

Occurrenceprimordial

CAS Number7440-52-0

Electron Configuration

Energy

↿⇂

↿

Isotopes of Erbium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
¹⁶²Er	161.928780	0.139%	Stable	Stable
¹⁶⁴Er	163.929200	1.601%	Stable	Stable
¹⁶⁶Er	165.930290	33.503%	Stable	Stable
¹⁶⁷Er	166.932050	22.869%	Stable	Stable
¹⁶⁸Er	167.932370	26.978%	Stable	Stable
¹⁷⁰Er	169.935460	14.91%	Stable	Stable

Interactive Visualization

Explore the 3D Bohr model of Erbium in our interactive viewer.

View 3D Model of Erbium