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Erbium (Er)

Erbium is a chemical element of the periodic table with chemical symbol Er and atomic number 68 with an atomic weight of 167.259 u and is classed as lanthanide. Erbium is solid at room temperature.

Erbium in the periodic table

Atomic number68
AppearanceSilvery white
Color Silver
Number of protons68 p+
Number of neutrons99 n0
Number of electrons68 e-
From Wikipedia, the free encyclopediaErbium is a chemical element in the lanthanide series, with symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements on Earth. As such, it is a rare earth element which is associated with several other rare elements in the mineral gadolinite from Ytterby in Sweden, where yttrium, ytterbium, and terbium were discovered.

Physical properties

Phase at STPSolid
Density9.066 g/cm3
Atomic weight167.259 u

Thermal properties

Melting point1802 K
1528.85 °C
2783.93 °F
Boiling point3141 K
2867.85 °C
5194.13 °F
Heat of vaporization292.88 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)1.24
Electron affinity30.1 kJ/mol
Oxidation states0, +1, +2, +3
(a basic oxide)
Ionization energies
  1. 589.3 kJ/mol
  2. 1150 kJ/mol
  3. 2194 kJ/mol
  4. 4120 kJ/mol

Electron configuration for erbium

Electron configuration
Shorthand configuration
[Xe] 4f12 6s2
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f12 5s2 5p6 6s2
Electron configuration chart
Electrons per shell2, 8, 18, 30, 8, 2
Valence electrons 2
Valency electrons 3
Bohr model
ErbiumElectron shell for Erbium, created by Injosoft ABEr
Figure: Shell diagram of Erbium (Er) atom.
Orbital Diagram

The history of Erbium

DiscoveryCarl Gustaf Mosander (1843)
Discovery of erbium
Erbium (for Ytterby, a village in Sweden) was discovered by Carl Gustaf Mosander in 1843. Mosander was working with a sample of what was thought to be the single metal oxide yttria, derived from the mineral gadolinite. He discovered that the sample contained at least two metal oxides in addition to pure yttria, which he named "erbia" and "terbia" after the village of Ytterby where the gadolinite had been found. Mosander was not certain of the purity of the oxides and later tests confirmed his uncertainty. Not only did the "yttria" contain yttrium, erbium, and terbium; in the ensuing years, chemists, geologists and spectroscopists discovered five additional elements: ytterbium, scandium, thulium, holmium, and gadolinium.


List of unique identifiers for Erbium in various chemical registry databases
CAS Number7440-52-0
ChemSpider ID22416
EC number231-160-1
PubChem CID Number23980