Erbium (pronEng|ˈɝbiəm) is a
chemical elementwith the symbol Er and atomic number68. A rare, silvery, white metallic lanthanide, erbium is a solidin its normal state. It is a rare earth elementassociated with several other rare elements in the mineral gadolinitefrom Ytterbyin Sweden.
A trivalent element, pure erbium
metalis 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 has characteristic sharp absorption spectrabands in visible light, ultraviolet, and near infrared. Otherwise it looks much like the other rare earths. Its sesquioxideis 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 someWho? to be able to stimulate metabolismFact|date=October 2007. 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 lasersand optical amplifiers. The 1550nm wavelength is especially important for optical communicationsbecause standard single mode optical fibershave minimal loss at this particular wavelength.A large variety of medical applications can be found (i.e. dermatology, dentistry) by utilizing the 2940nm emission (see ) which is highly absorbed in water (about 12000 1/cm).
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
nuclear poison, as in neutron-absorbing control rods.
* Used as a
dopantin fiber-optic laser amplifiers.
* When added to
vanadiumas an alloy, erbium lowers hardness and improves workability.
Erbium oxidehas a pink color, and is sometimes used as a colorant for glassand porcelain. The glass is then often used in sunglassesand cheap jewelry.
* Erbium is also used to provide the pink color in cubic zirconia, also used in inexpensive jewelry. The pink color is especially intense and beautiful under white
* Erbium-doped optical silica-glass fibers are the active element in
erbium-doped fiber amplifiers (EDFAs), which are widely used in optical communications. The same fibers can be used to create fiber lasers. Co-doping of optical fiber with Er and Yb is used in high-power Er/Yb fiber lasers, which gradually replace CO2 lasers for metal welding and cutting applications. Erbium can also be used in erbium-doped waveguide amplifiers.
* Erbium is commonly used in YAG lasers for cosmetic laser procedures and mild to medium depth skin resurfacing. [Wrinkles.org]
* An erbium-
nickelalloy Er3Ni has an unusually high specific heat capacity at liquid-helium temperatures and is used in cryocoolers; a mixture of 65% Er3Co and 35% Er0.9Yb0.1Ni by volume improves the specific heat capacity even more [cite book | title=Advances in Cryogenic Engineering volume 39a | editor=Peter Kittel] .
Ytterby, a town in Sweden) was discovered by Carl Gustaf Mosanderin 1843. Mosander separated "yttria" from the mineral gadoliniteinto 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 Urbainand Charles James. Reasonably pure metal wasn't produced until 1934 when workers reduced the anhydrous chloridewith potassiumvapor. It was only in the 1990's that the price for Chinese-derived erbium oxide became low enough for erbium to be considered for use as a colorant in art glass. Erbium is the only colorant to give a stable pink color in glass. Erbium colored art glass is currently being produced in China, and has recently been produced by Fenton, in the United States.
Like other rare earths, this element is never found as a free element in nature but is found bound in
monazitesand ores. It has historically been very difficult and expensive to separate rare earths from each other in their ores but ion-exchangeproduction 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 xenotimeand euxenite, and most recently, the ion adsorption clays of southern China. In the high-yttrium versions of these ore concentrates, yttrium is about two-thirds of the total by weight, and erbia is about 4-5%. This is enough erbium to impart a distinct pink color to the solution when the concentrate is dissolved in acid. This color behavior is highly similar to what Mosander and the other early workers in the lanthanides would have seen, in their extracts from Ytterby gadolinite.
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 (33.503% natural abundance). 29 radioisotopes have been characterized, with the most stable being Er-169 with a half lifeof 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 radioactiveisotopes 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 13 meta states, with the most stable being Er-167m (t½ 2.269 seconds).
The isotopes of erbium range in
atomic weightfrom 142.9663 u (Er-143) to 176.9541 u (Er-177). The primary decay modebefore 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. Metallic erbium in dust form presents a fire and explosion hazard.
In popular culture
Carl Sagan's science-fiction novel" Contact (novel)", "dowels" constructed in large part of erbium play a prominent role in the operation of a machine of extraterrestrial origin designed for interstellar travel.
* [http://periodic.lanl.gov/elements/68.html Los Alamos National Laboratory – Erbium]
* "Guide to the Elements – Revised Edition", Albert Stwertka, (Oxford University Press; 1998) ISBN 0-19-508083-1
* [http://education.jlab.org/itselemental/ele068.html It's Elemental – Erbium]
* Chemical Elements: Erbium http://www.chemicalelements.com/elements/er.html
* [http://www.webelements.com/webelements/elements/text/Er/index.html WebElements.com – Erbium] (also used as a reference)
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