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Name , symbol , atomic number Erbium, Er, 68
Element category Lanthanoids
Group , period , block La , 6 , f
Appearance silvery white
CAS number 7440-52-0
EC number 231-160-1
ECHA InfoCard 100.028.327
Mass fraction of the earth's envelope 2.3 ppm
Atomic mass 167,259 (3) et al
Atomic radius (calculated) 175 (226) pm
Covalent radius 189 pm
Electron configuration [ Xe ] 4 f 12 6 s 2
1. Ionization energy 6th.1077 (10) eV589.3 kJ / mol
2. Ionization energy 11.916 (20) eV1 149.7 kJ / mol
3. Ionization energy 22nd.70 (3) eV2 190 kJ / mol
4. Ionization energy 42.42 (4) eV4 090 kJ / mol
5. Ionization energy 65.1 (4) eV6 280 kJ / mol
Physical state firmly
Crystal structure hexagonal
density 9.045 g / cm 3 (25 ° C )
magnetism paramagnetic ( Χ m = 0.033)
Melting point 1802 K (1529 ° C)
boiling point 3173 K (2900 ° C)
Molar volume 18.46 · 10 −6 m 3 · mol −1
Heat of evaporation 280 kJ / mol
Heat of fusion 19.9 kJ mol −1
Electric conductivity 1.16 · 10 6 A · V −1 · m −1
Thermal conductivity 15 W m −1 K −1
Oxidation states 3
Normal potential −2.32 V
(Er 3+ + 3 e - → Er)
Electronegativity 1.24 ( Pauling scale )
isotope NH t 1/2 ZA ZE (M eV ) ZP
162 he 0.14% Stable
163 he {syn.} 75 min ε 1,210 163 Ho
164 he 1.61% Stable
165 he {syn.} 10.36 h ε 0.376 165 Ho
166 he 33.6% Stable
167 he 22.95% Stable
168 he 26.8% Stable
169 he {syn.} 9.40 d β - 0.351 169 Tm
170 he 14.9% Stable
For other isotopes see list of isotopes
NMR properties
number I
γ in
rad · T −1 · s −1
E r  ( 1 H) f L at
B = 4.7 T
in MHz
167 he +7/2 7.715 · 10 6 2.88
safety instructions
GHS labeling of hazardous substances


02 - Highly / extremely flammable


H and P phrases H: 228
P: 210
As far as possible and customary, SI units are used.
Unless otherwise noted, the data given apply to standard conditions .

Erbium is a chemical element with the element symbol Er and the atomic number 68. In the periodic table it is in the group of lanthanoids and is therefore also one of the rare earth metals . The name is derived from the Ytterby mine near Stockholm , as well as that of ytterbium , terbium and yttrium .


Erbium was discovered by Carl Gustav Mosander in 1843 . However, the supposedly pure oxide was a mixture of the oxides from erbium, scandium, holmium, thulium and ytterbium.

The chemists Marc Delafontaine and Nils Johan Berlin made a contribution to the later clarification . The French chemist Georges Urbain and the American chemist Charles James produced pure erbium oxide in 1905 .


Erbium is a rare metal (3.5 ppm ) that does not occur naturally in its pure form, but mainly in the mineral monazite.

Extraction and presentation

After a complex separation of the other erbium companions, the oxide is converted to erbium fluoride with hydrogen fluoride. Subsequently, calcium is used to reduce to metallic erbium with the formation of calcium fluoride . The removal of remaining calcium residues and impurities takes place in an additional remelting process in a vacuum .



Physical Properties

The silver-white shiny metal of the rare earths is malleable, but also quite brittle.

Chemical properties

Erbium turns gray in air, but is then quite stable. At higher temperatures it burns to the sesquioxide Er 2 O 3 . It reacts with water to form the hydroxide, producing hydrogen. It dissolves in mineral acids with the formation of hydrogen.

In its compounds it is in the +3 oxidation state, the Er 3+ cations form pink solutions in water. Solid salts are also colored pink.


Erbium-doped optical fibers are used for optical amplifiers that are able to amplify a light signal without converting it into an electrical signal beforehand. Gold as a host material doped with a few hundred ppm erbium is used as a sensor material for magnetic calorimeters for high-resolution particle detection in physics and technology.

Along with other rare earth elements such as neodymium or holmium, erbium is used for doping laser crystals in solid-state lasers (Er: YAG laser, see also Nd: YAG laser ). The Er: YAG laser is mainly used in human medicine. It has a wavelength of 2940 nm and thus an extremely high absorption in tissue water of approx. 12000 per cm.

As a pure beta emitter is 169 He in nuclear medicine for therapy in the Radiosynoviorthesis used.

Many of its compounds, such as erbium chloride , are colored pink and are therefore used in pottery and glass blowing.


Web links

Commons : Erbium  - collection of images, videos and audio files
Wiktionary: Erbium  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Harry H. Binder: Lexicon of the chemical elements. S. Hirzel Verlag, Stuttgart 1999, ISBN 3-7776-0736-3 .
  2. The values ​​for the properties (info box) are taken from (Erbium) , unless otherwise stated .
  3. CIAAW, Standard Atomic Weights Revised 2013 .
  4. a b c d e entry on erbium in Kramida, A., Ralchenko, Yu., Reader, J. and NIST ASD Team (2019): NIST Atomic Spectra Database (ver. 5.7.1) . Ed .: NIST , Gaithersburg, MD. doi : 10.18434 / T4W30F ( ). Retrieved June 13, 2020.
  5. a b c d e entry on erbium at WebElements, , accessed on June 13, 2020.
  6. ^ NN Greenwood, A. Earnshaw: Chemistry of the elements. 1st edition. VCH, Weinheim 1988, ISBN 3-527-26169-9 , p. 1579.
  7. Robert C. Weast (Ed.): CRC Handbook of Chemistry and Physics . CRC (Chemical Rubber Publishing Company), Boca Raton 1990, ISBN 0-8493-0470-9 , pp. E-129 to E-145. Values ​​there are based on g / mol and given in cgs units. The value specified here is the SI value calculated from it, without a unit of measure.
  8. a b Yiming Zhang, Julian RG Evans, Shoufeng Yang: Corrected Values ​​for Boiling Points and Enthalpies of Vaporization of Elements in Handbooks. In: Journal of Chemical & Engineering Data . 56, 2011, pp. 328-337, doi: 10.1021 / je1011086 .
  9. a b Entry on erbium, powder in the GESTIS substance database of the IFA , accessed on April 2nd, 2018(JavaScript required) .
  10. The History of the Erbium .
  11. David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Geophysics, Astronomy, and Acoustics; Abundance of Elements in the Earth's Crust and in the Sea, pp. 14-18.
  12. a b Gerd Hintermaier-Erhard: Everything is chemistry! The chemical elements and how we use them . Dorling Kindersley Verlag, Munich 2017, ISBN 978-3-8310-3339-3 .
  13. ^ German Society for Nuclear Medicine - Guideline of Radiosynoviorthesis .