Dysprosium

Dysprosium (pronEng|dɪsˈproʊziəm) is a chemical element with the symbol Dy and atomic number 66.

Characteristics

Dysprosium is a rare earth element that 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.

Applications

Dysprosium is used, in conjunction with vanadium and other elements, in making laser materials. Its high thermal neutron absorption cross-section and melting point also suggests that it is useful for nuclear control rods. Dysprosium oxide (also known as "dysprosia"), with nickel cement compounds, 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 infrared radiation 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 coercivity for demanding applications such as drive motors for hybrid electric vehicles [cite web
title=Supply and Demand, Part 2
first=Peter
last=Campbell
publisher=Princeton Electro-Technology, Inc.
year=2008
month=February
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 alloy that 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.

History

Dysprosium was first identified in Paris in 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 exchange by Frank Spedding in 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 ]

Occurrence

Dysprosium is never encountered as a free element, but is found in many minerals, including xenotime, fergusonite, gadolinite, euxenite, polycrase, blomstrandine, monazite and bastnäsite; often with erbium and holmium or other rare earth elements. Currently, most dysprosium is being obtained from the ion-adsorption clay ores of southern China. In the high-yttrium version 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).

Compounds

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:

* Fluorides: DyF3
* Chlorides: DyCl2, DyCl3
* Bromides: DyBr2, DyBr3
* Iodides: DyI2, DyI3
* Oxides: Dy2O3
* Sulfides: Dy2S3
* Nitrides: DyN

"See also ."

Isotopes

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-life of 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).

The primary decay mode before 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 terbium isotopes, and the primary products after are holmium isotopes.

Precautions

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.

See also

* Materials science

Notes

External links

* [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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Look at other dictionaries:

  • Dysprosium — Terbium ← Dysprosium → Holmium …   Wikipédia en Français

  • dysprosium — [ disprozjɔm ] n. m. • 1886; gr. dusprositos « difficile à atteindre » ♦ Chim. Élément atomique (Dy; no at. 66; m. at. 162,5), métal du groupe des terres rares d éclat métallique analogue à celui de l argent. ● dysprosium nom masculin (grec… …   Encyclopédie Universelle

  • dysprosium — Symbol: Dy Atomic number: 66 Atomic weight: 162.50 Metallic with a bright silvery white lustre. Dysprosium belongs to the lanthanoids. It is relatively stable in air at room temperatures, it will however dissolve in mineral acids, evolving… …   Elements of periodic system

  • Dysprosium — Dys*pro si*um, n. [NL., fr. Gr. dyspro sitos hard to get at.] (Chem.) An element of the rare earth group. Symbol Dy; at. wt., 162.5. [Webster 1913 Suppl.] …   The Collaborative International Dictionary of English

  • dysprosium — element, obtained 1906 from an earth discovered in 1886, the last to be extracted from the complex earth called yttria, and named dysprosia in reference to the difficulty of obtaining it, from Gk. dysprositos hard to get at, difficult of access,… …   Etymology dictionary

  • dysprosium — [dis prō′zē əm, dis prō′sēəm] n. [ModL < Gr dysprositos, difficult of access < dys , DYS + prositos, approachable < prosienai, come to < pros, toward + ienai, to go (see ION): so named (1886) by its discoverer, Fr chemist P. E. Lecoq… …   English World dictionary

  • Dysprosium — Eigenschaften …   Deutsch Wikipedia

  • Dysprosium — Dys|pro|si|um 〈n.; s; unz.; chem. 〉 chem. Element, Metall der seltenen Erden [zu grch. dysprositos „schwer zu erlangen“] * * * Dys|pro|si|um [griech. dysprósitos = schwer zugänglich; ↑ ium (1)], das; s; Symbol: Dy; chem. Element, Protonenzahl 66 …   Universal-Lexikon

  • dysprosium — /dis proh see euhm, shee /, n. Chem. a rare earth metallic element, highly reactive and paramagnetic, found in small amounts in various rare earth minerals, as euxenite and monazite: used to absorb neutrons in nuclear reactors. Symbol: Dy; at. wt …   Universalium

  • Dysprosium — disprozis statusas T sritis fizika atitikmenys: angl. dysprosium vok. Dysprosium, n rus. диспрозий, m pranc. dysprosium, m …   Fizikos terminų žodynas

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