Dysprosium (pronEng|dɪsˈproʊziəm) is a
chemical elementwith the symbol Dy and atomic number66.
Dysprosium is a
rare earth elementthat has a metallic, bright silver luster, relatively stable in air at room temperature, but dissolving readily in dilute or concentrated mineral acids with the emission of hydrogen. It is soft enough to be cut with bolt-cutters (but not with a knife), and can be machined without sparking if overheating is avoided. Dysprosium's characteristics can be greatly affected even by small amounts of impurities.
Dysprosium is used, in conjunction with
vanadiumand other elements, in making lasermaterials. Its high thermal neutronabsorption cross-section and melting point also suggests that it is useful for nuclear control rods. Dysprosium oxide (also known as "dysprosia"), with nickel cementcompounds, which absorb neutrons readily without swelling or contracting under prolonged neutron bombardment, is used in neutron-absorbing control rods in nuclear reactors. Dysprosium- cadmium chalcogenides are sources of infraredradiation for studying chemical reactions. Furthermore, dysprosium is used for manufacturing computer hard drives and compact discs. Because it is highly paramagnetic, dysprosium has been used as a contrast agent in magnetic resonance imaging. Neodymium-iron-boron magnets can have up to 6% of the neodymium substituted with dysprosium to raise the coercivityfor demanding applications such as drive motors for hybrid electric vehicles [cite web
title=Supply and Demand, Part 2
publisher=Princeton Electro-Technology, Inc.
url=http://www.magnetweb.com/Col05.htm] ; this leads to a demand for up to 100 grams of dysprosium per hybrid car sold, which under most predictions of hybrid vehicle demand would require new sources of dysprosium to be found.
As a component of
Terfenol-D(an alloythat expands or contracts to a high degree in the presence of a magnetic field), dysprosium is of use in actuators, sensors and other magnetomechanical devices.
Below 85K dysprosium is ferromagnetic, with a high susceptibility. It is often used for the fabrication of nanomagnets, particularly in research. Its usefulness, however, is limited by its high readiness to oxidise.
Dysprosium was first identified in
Parisin 1886 by French chemist Paul Émile Lecoq de Boisbaudran. He was only able to isolate dysprosium from its oxide after more than 30 attempts to dissolve it in acid. Upon succeeding, he named the element "dysprosium" from the Greek "dysprositos", meaning "hard to get". However, the element itself was not isolated in relatively pure form until after the development of ion exchangeby Frank Speddingin the early 1950s.cite book| last = Emsley| first = John| title = Nature's Building Blocks| publisher = Oxford University Press| date = 2001| location = Oxford| pages = 129-132| isbn = 0-19-850341-5 ]
Dysprosium is never encountered as a free element, but is found in many
minerals, including xenotime, fergusonite, gadolinite, euxenite, polycrase, blomstrandine, monaziteand bastnäsite; often with erbiumand holmiumor other rare earth elements. Currently, most dysprosium is being obtained from the ion-adsorption clay ores of southern China. In the high- yttriumversion of these, dysprosium happens to be the most abundant of the heavy lanthanides, comprising up to 7-8% of the concentrate (as compared to about 65% for yttrium).
Nearly all dysprosium compounds are in the +3 oxidation state, and are highly
paramagnetic. Holmium(III) oxide(Ho2O3) and Dysprosium(III) oxide (Dy2O3) are the most powerfully paramagnetic substances known.
Dysprosium compounds include:
"See also ."
Naturally occurring dysprosium is composed of 7 stable
isotopes, 156Dy, 158Dy, 160Dy, 161Dy, 162Dy, 163Dy and 164Dy, with 164-Dy being the most abundant (28.18% natural abundance). 28 radioisotopes have been characterized, with the most stable being 154Dy with a half-lifeof 3.0x106 years, 159Dy with a half-life of 144.4 days, and 166Dy with a half-life of 81.6 hours. All of the remaining radioactive isotopes have half-lifes that are less than 10 hours, and the majority of these have half lifes that are less than 30 seconds. This element also has 5 meta states, with the most stable being 165mDy (t½ 1.257 minutes), 147mDy (t½ 55.7 seconds) and 145mDy (t½ 13.6 seconds).
decay modebefore the most abundant stable isotope, 164Dy, is electron capture, and the primary mode after is beta minus decay. The primary decay products before 164Dy are terbiumisotopes, and the primary products after are holmiumisotopes.
As with the other lanthanides, dysprosium compounds are of low to moderate
toxicity, although their toxicity has not been investigated in detail. Dysprosium does not have any known biological properties.
* [http://www.webelements.com/webelements/elements/text/Dy/key.html WebElements.com – Dysprosium]
* [http://education.jlab.org/itselemental/ele066.html It's Elemental – Dysprosium]
* [http://periodic.lanl.gov/elements/66.html Los Alamos National Laboratory – Dysprosium]
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