2007 Schools Wikipedia Selection. Related subjects: Chemical elements

68 holmiumerbiumthulium


Periodic Table - Extended Periodic Table
Name, Symbol, Number erbium, Er, 68
Chemical series lanthanides
Group, Period, Block n/a, 6, f
Appearance silvery white
Atomic mass 167.259 (3) g/mol
Electron configuration [Xe] 4f12 6s2
Electrons per shell 2, 8, 18, 30, 8, 2
Physical properties
Phase solid
Density (near r.t.) 9.066 g·cm−3
Liquid density at m.p. 8.86 g·cm−3
Melting point 1802  K
(1529 ° C, 2784 ° F)
Boiling point 3141 K
(2868 ° C, 5194 ° F)
Heat of fusion 19.90 kJ·mol−1
Heat of vaporization 280 kJ·mol−1
Heat capacity (25 °C) 28.12 J·mol−1·K−1
Vapor pressure
P/Pa 1 10 100 1 k 10 k 100 k
at T/K 1504 1663 (1885) (2163) (2552) (3132)
Atomic properties
Crystal structure hexagonal
Oxidation states 3
( basic oxide)
Electronegativity 1.24 (Pauling scale)
Ionization energies
( more)
1st: 589.3 kJ·mol−1
2nd: 1150 kJ·mol−1
3rd: 2194 kJ·mol−1
Atomic radius 175 pm
Atomic radius (calc.) 226 pm
Magnetic ordering no data
Electrical resistivity ( r.t.) (poly) 0.860 µΩ·m
Thermal conductivity (300 K) 14.5 W·m−1·K−1
Thermal expansion ( r.t.) (poly)
12.2 µm/(m·K)
Speed of sound (thin rod) (20 °C) 2830 m/s
Young's modulus 69.9 GPa
Shear modulus 28.3 GPa
Bulk modulus 44.4 GPa
Poisson ratio 0.237
Vickers hardness 589 MPa
Brinell hardness 814 MPa
CAS registry number 7440-52-0
Selected isotopes
Main article: Isotopes of erbium
iso NA half-life DM DE ( MeV) DP
160Er syn 28.58 h ε 0.330 160Ho
162Er 0.14% Er is stable with 94 neutrons
164Er 1.61% Er is stable with 96 neutrons
165Er syn 10.36 h ε 0.376 165Ho
166Er 33.6% Er is stable with 98 neutrons
167Er 22.95% Er is stable with 99 neutrons
168Er 26.8% Er is stable with 100 neutrons
169Er syn 9.4 d β- 0.351 169Tm
170Er 14.9% Er is stable with 102 neutrons
171Er syn 7.516 h β- 1.490 171Tm
172Er syn 49.3 h β- 0.891 172Tm

Erbium ( IPA: /ˈɛː(r)biəm/) is a chemical element in the periodic table that has the symbol Er and atomic number 68. A rare silvery metallic lanthanide rare earth element, erbium is associated with several other rare elements in the mineral gadolinite from Ytterby in Sweden.

Notable characteristics

A trivalent element, pure erbium metal is malleable (or easily shaped), soft yet stable in air and does not oxidize as quickly as some other rare-earth metals. Its salts are rose-colored and the element gives a characteristic sharp absorption spectra in visible light, ultraviolet, and near infrared. Otherwise it looks much like the other rare earths. Its sesquioxide is called erbia. Erbium's properties are to a degree dictated by the kind and amount of impurities present. Erbium does not play any known biological role but is thought by some to be able to stimulate metabolism. Erbium doped glasses or crystals can be used as optical amplification media, where erbium ions are optically pumped at around 980nm or 1480nm and then radiate light at 1550nm. This process can be used to create lasers and optical amplifiers. The 1550nm wavelength is especially important for optical communications becase standard single mode optical fibers have minimal loss at this particular wavelength.


Erbium's everyday uses are varied. It is commonly used as a photographic filter and because of its resilience it is useful as a metallurgical additive. Other uses:

  • Used in nuclear technology as a neutron absorber.
  • Used as a dopant in fibre optic laser amplifiers.
  • When added to vanadium as an alloy erbium lowers hardness and improves workability.
  • Erbium oxide has a pink colour and is sometimes used as a colorant for glass and porcelain. The glass is then often used in sunglasses and cheap jewelry.
  • Erbium doped optical silica-glass fibers is the active element in erbium-doped fibre amplifiers (EDFAs) which are widely used in optical communications. The same fibers can be used to create fibre lasers. Co-doping of optical fiber with Er and Yb is used in high power Er/Yb fibre lasers, which gradually replace CO2 lasers for metal welding and cutting applications. Erbium can also be used in erbium-doped waveguide amplifiers.


Erbium (for Ytterby, a town in Sweden) was discovered by Carl Gustaf Mosander in 1843. Mosander separated "yttria" from the mineral gadolinite into three fractions which he called yttria, erbia, and terbia. He named the new element after the town of Ytterby where large concentrations of yttria and erbium are located. Erbia and terbia, however, were confused at this time. After 1860, terbia was renamed erbia and after 1877 what had been known as erbia was renamed terbia. Fairly pure Er2O3 was independently isolated in 1905 by Georges Urbain and Charles James. Reasonably pure metal wasn't produced until 1934 when workers reduced the anhydrous chloride with potassium vapor.


Like other rare earths, this element is never found as a free element in nature but is found bound in monazite sand ores. It has historically been very difficult and expensive to separate rare earths from each other in their ores but ion-exchange production techniques developed in the late 20th century have greatly brought down the cost of production of all rare-earth metals and their chemical compounds. The principal commercial sources of erbium are from the minerals xenotime and euxenite. Metallic erbium in dust form presents a fire and explosion hazard.


Naturally occurring erbium is composed of 6 stable isotopes, Er-162, Er-164, Er-166, Er-167, Er-168, and Er-170 with Er-166 being the most abundant (33.6% natural abundance). 23 radioisotopes have been characterized, with the most stable being Er-169 with a half life of 9.4 days, Er-172 with a half-life of 49.3 hours, Er-160 with a half-life of 28.58 hours, Er-165 with a half-life of 10.36 hours, and Er-171 with a half life of 7.516 hours. All of the remaining radioactive isotopes have half-lifes that are less than 3.5 hours, and the majority of these have half lifes that are less than 4 minutes. This element also has 6 meta states, with the most stable being Er-167m (t½ 2.269 seconds).

The isotopes of erbium range in atomic weight from 144.957 amu (Er-145) to 173.944 amu (Er-174). The primary decay mode before the most abundant stable isotope, Er-166, is electron capture, and the primary mode after is beta decay. The primary decay products before Er-166 are element 67 (holmium) isotopes, and the primary products after are element 69 (thulium) isotopes.


As with the other lanthanides, erbium compounds are of low to moderate toxicity, although their toxicity has not been investigated in detail.

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