Erbium Element Facts / Chemistry

The chemical element erbium is classed as a lanthanide and rare earth metal. It was discovered in 1843 by Carl Gustaf Mosander.

Erbium metal. Photo by Tomihahndorf.
Erbium metal.

Data Zone

Classification: Erbium is a lanthanide and rare earth metal
Color: silvery-white
Atomic weight: 167.26
State: solid
Melting point: 1530 oC, 1803 K
Boiling point: 2860 oC, 3133 K
Electrons: 68
Protons: 68
Neutrons in most abundant isotope: 98
Electron shells: 2,8,18,30,8,2
Electron configuration: [Xe] 4f12 6s2
Density @ 20oC: 9.05 g/cm3
Show more, including: Heats, Energies, Oxidation, Reactions, Compounds, Radii, Conductivities
Atomic volume: 18.4 cm3/mol
Structure: hexagonal close packed
Specific heat capacity 0.17 J g-1 K-1
Heat of fusion 19.90 kJ mol-1
Heat of atomization 317 kJ mol-1
Heat of vaporization 292.88 kJ mol-1
1st ionization energy 588.7 kJ mol-1
2nd ionization energy 1151 kJ mol-1
3rd ionization energy 2194 kJ mol-1
Electron affinity
Minimum oxidation number 0
Min. common oxidation no. 0
Maximum oxidation number 3
Max. common oxidation no. 3
Electronegativity (Pauling Scale) 1.24
Polarizability volume 22.7 Å3
Reaction with air mild, ⇒ Er2O3
Reaction with 15 M HNO3 mild, ⇒ Er(NO3)3
Reaction with 6 M HCl mild, ⇒ H2, ErCl3
Reaction with 6 M NaOH
Oxide(s) Er2O3 (erbia)
Hydride(s) ErH2, ErH3
Chloride(s) ErCl3
Atomic radius 175 pm
Ionic radius (1+ ion)
Ionic radius (2+ ion)
Ionic radius (3+ ion) 103 pm
Ionic radius (1- ion)
Ionic radius (2- ion)
Ionic radius (3- ion)
Thermal conductivity 14.5 W m-1 K-1
Electrical conductivity 1.2 x 106 S m-1
Freezing/Melting point: 1530 oC, 1803 K

Rare-earth refining

Getting high purity research quality rare-earth metals takes time. First rare earth oxides, like the yellow (cerium), black (praseodymium) and blue (neodymium) oxides in the dishes are exposed to the highly reactive gas hydrogen fluoride. This turns the powder into a fluoride, such as the bright green praseodymium fluoride crystals (far right). A reduction reaction and further processing turns the rare-earth fluorides into their pure metal forms, (from top center) scandium disc, dysprosium disc resting on a sheet of sublimated dysprosium and gadolinium cylinder. Photo: Ames Laboratory .

A brief introduction to the lanthanides.

Discovery of Erbium

Dr. Doug Stewart

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

Four years earlier Mosander had discovered lanthanum. His former supervisor, Jöns Berzelius, had discovered the new element cerium in cerite. Mosander continued to study cerite and was rewarded with the discovery of lanthanum. (1)

In 1843, Mosander began studying the mineral gadolinite. Gadolinite contained yttria (yttrium oxide) in which Johan Gadolin had discovered the element yttrium in 1794. Mosander wondered if he might repeat his earlier triumph and find another new element hiding with a known element.

Using ammonium hydroxide he precipitated fractions of different basicity from yttria. In these fractions he found two differently colored, previously unknown substances. These he called erbia and terbia; they contained the new rare earth metals erbium and terbium. Mosander had now discovered three new elements, all rare earths, and all in minerals other scientists had discarded after making their own discoveries. (2), (3), (4)

Mosander named erbium and terbium after the Ytterby Mine in Sweden, the source of gadolinite mineral they were discovered in. (The elements yttrium and ytterbium were also named after the same mine.)

The identities (and even the existence) of a number of rare earth elements was settled finally by George Urbain in Paris, who carried out tens of thousands of fractional crystallizations of rare earth salts.

Crystallizations could take years to produce small samples of pure salts.

Urbain finally put to rest uncertainty about the identities of pure earths whose salts had never before been completely free of other rare earth salts.

Urbain found there were fifteen rare earth metals – we now recognize seventeen – one of which was erbium. In the process, he discovered the rare earth lutetium, adding his own name to the list of scientists who have discovered elements. (5), (6), (7), (8), (9)

Metallic erbium was not isolated until 1935 by W. Klemm and H. Bommer who reduced its anhydrous chloride with potassium vapor. (10)


A purple laser beam slows erbium atoms emerging from an oven at 1300oC, in preparation for trapping and cooling. The unusual properties of erbium atoms and the new capability to trap them could lead to development of novel technologies. Photo: NIST


Appearance and Characteristics

Harmful effects:

Erbium is considered to be moderately toxic.


Erbium is a bright, soft, malleable, silvery-white metal.

It is one of the rare earth metals.

The metal slowly tarnishes in air, reacts slowly with water and dissolves in acids.

When present in compounds, erbium exists mostly in the trivalent state, Er3+. Erbium salts are a rose pink color.

Uses of Erbium

Erbium isotopes are good neutron absorbers and are used in nuclear reactor control rods.

The oxide erbia is used as a pink coloring agent in glazes and glasses.

Erbium is used in alloys especially with vanadium to decrease the hardness of metals.

It is also used in amplifiers and lasers.

Erbium is used in photographic filters to absorb infrared light.

Erbium is also used in yttrium aluminum garnet (YAG) medical lasers for procedures involving skin resurfacing such as acne scars, mole removal tattoo removal and warts.

Abundance and Isotopes

Abundance earth’s crust: 3 parts per million by weight, 0.4 parts per million by moles

Abundance solar system: 1 part per billion by weight, 10 parts per trillion by moles

Cost, pure: $540 per 100g

Cost, bulk: $65 per 100g


Erbium is not found free in nature but is found in a number of minerals: mainly monazite, bastnasite, xenotime and euxenite. Commercially it is refined from xenotime and euxenite using a complex ion-exchange process. Erbium is then isolated from the oxide or its salts by heating at 1450 oC with calcium in an argon atmosphere.

Isotopes: Erbium has 31 isotopes whose half-lives are known, with mass numbers 145 to 175. Naturally occurring erbium is a mixture of six isotopes and they are found in the percentages shown: 162Er (0.1%), 164Er (1.6%), 166Er (33.6%), 167Er (22.9%), 168Er (26.8%) and 170Er (14.9%). The most abundant isotope is 166Er at 33.6%.


1. Latanium, a New Metal., The London and Edinburgh Philosophical Magazine and Journal of Science, 1839, 14, p3901.
2. Mary Elvira Weeks, The discovery of the elements. XVI. The rare earth elements., J. Chem. Educ., 1932, p1751.
3. Per Enghag, Encyclopedia of the elements: technical data, history, processing, applications., John Wiley and Sons, 2004, p447.
4. Paul Caro, Rare earths., Editorial Complutense., 1998, p35.
5. Georges Champetier and Charlotte H. Boatner, Georges Urbain., 1940, J. Chem. Educ., p103.
6. G. Eberhard, A Spectroscopic Investigation of Dr. Urbain’s Preparations of Terbium., Astrophysical Journal., 1906 vol. 24, p309.
7. Ralph P. Oesper, Georges Urbain., 1938, J. Chem. Educ., p201.
8. G. Urbain, On a yttria earth neighboring gadolinium. Comptes Rendus, 1904, 139, p736.
9. G. Urbain, On the isolation of terbium., Comptes Rendus, 1905, 141, p521.
10. Charles T. Lynch, CRC handbook of materials science., CRC Press, 1974, p.17.

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  1. what does it react with?

    • Hi Julia, from the Data Zone near the page top:

      Reaction with air mild, ⇒ Er2O3
      Reaction with 15 M HNO3 mild, ⇒ Er(NO3)3
      Reaction with 6 M HCl mild, ⇒ H2, ErCl3
      Reaction with 6 M NaOH –
      Oxide(s) Er2O3 (erbia)
      Hydride(s) ErH2, ErH3
      Chloride(s) ErCl3