|Name, Symbol, Number||dysprosium, Dy, 66|
|Group, Period, Block||n/a, 6, f|
|Appearance||silvery white |
|Atomic mass||162.500(1) g/mol|
|Electron configuration||[Xe] 4f10 6s2|
|Electrons per shell||2, 8, 18, 28, 8, 2|
|Density (near r.t.)||8.540 g/cm³|
|Liquid density at m.p.||8.37 g/cm³|
|Melting point||1680 K|
(1407 °C, 2565 °F)
|Boiling point||2840 K|
(2567 °C, 4653 °F)
|Heat of fusion||11.06 kJ/mol|
|Heat of vaporization||280 kJ/mol|
|Heat capacity||(25 °C) 27.7 J/(mol·K)|
(weakly basic oxide)
|Electronegativity||1.22 (Pauling scale)|
|1st: 573.0 kJ/mol|
|2nd: 1130 kJ/mol|
|3rd: 2200 kJ/mol|
|Atomic radius||175 pm|
|Atomic radius (calc.)||228 pm|
|Magnetic ordering||nonmagnetic at r.t.,|
|Electrical resistivity||(r.t.) (α, poly) 926 nΩ·m|
|Thermal conductivity||(300 K) 10.7 W/(m·K)|
|Thermal expansion||(r.t.) (α, poly)|
|Speed of sound (thin rod)||(20 °C) 2710 m/s|
|Speed of sound (thin rod)||(r.t.) (α form) 61.4 m/s|
|Shear modulus||(α form) 24.7 GPa|
|Bulk modulus||(α form) 40.5 GPa|
|Poisson ratio||(α form) 0.247|
|Vickers hardness||540 MPa|
|Brinell hardness||500 MPa|
|CAS registry number||7429-91-6|
Dysprosium (chemical symbol Dy, atomic number 66) is a rare earth element that has a metallic, bright silver luster.
Dysprosium is never encountered as a free element but is found in many minerals, including xenotime, fergusonite, gadolinite, euxenite, polycrase, blomstrandine, monazite, and bastnasite. It often occurs with erbium, holmium, and other rare earth elements.
Dysprosium was first identified in Paris in 1886 by French chemist Paul Émile Lecoq de Boisbaudran. However, the element itself was not isolated in relatively pure form until after the development of ion exchange and metallographic reduction techniques in the 1950s. The name dysprosium is derived from the Greek word δυσπροσιτος [dysprositos], meaning "hard to obtain."
Dysprosium is an inner transition metal (or lanthanide) that lies in period six of the periodic table, between terbium and holmium. It is relatively stable in air at room temperature, but dissoves 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.
Naturally occurring dysprosium is composed of seven stable isotopes—156-Dy, 158-Dy, 160-Dy, 161-Dy, 162-Dy, 163-Dy and 164-Dy—with 164-Dy being the most abundant (28.18 percent natural abundance). 28 radioisotopes have been characterized, with the most stable being 154-Dy with a half-life of 3.0E+6 years, 159-Dy with a half-life of 144.4 days, and 166-Dy with a half-life of 81.6 hours. All of the remaining radioactive isotopes have half-lives that are less than ten hours, and the majority of these have half lives that are less than 30 seconds. This element also has five meta states, with the most stable being 165m-Dy (t½ 1.257 minutes), 147m-Dy (t½ 55.7 seconds) and 145m-Dy (t½ 13.6 seconds).
The primary decay mode before the most abundant stable isotope, 164-Dy, is electron capture, and the primary mode after is beta minus decay. The primary decay products before 164-Dy are terbium isotopes, and the primary products after are holmium isotopes.
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:
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 for cooling rods in nuclear reactors. Dysprosium-cadmium chalcogenides are sources of infrared radiation for studying chemical reactions. Furthermore, dysprosium is used for manufacturing compact discs. Because it is highly paramagnetic, dysprosium has been used as a contrast agent in magnetic resonance imaging.
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.
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 role.
- ↑ The term "rare earth metals" (or "rare earth elements") is a trivial name applied to 16 chemical elements: scandium, yttrium, and 14 of the 15 lanthanides (excluding promethium), which occur naturally on Earth. Some definitions also include the actinides. The word "earth" is an obsolete term for oxide. The term "rare earth" is discouraged by the International Union of Pure and Applied Chemistry (IUPAC), as these elements are relatively abundant in the Earth's crust.
ReferencesISBN links support NWE through referral fees
- Chang, Raymond. Chemistry. 9th ed. New York: McGraw-Hill Science/Engineering/Math, 2006. ISBN 0073221031
- Cotton, F. Albert, and Geoffrey Wilkinson. Advanced Inorganic Chemistry. 4th ed. New York: Wiley, 1980. ISBN 0471027758
- Greenwood, N.N. and A. Earnshaw. Chemistry of the Elements. 2nd ed. Oxford, U.K.; Burlington, MA: Butterworth-Heinemann, Elsevier Science, 1998. ISBN 0750633654. Online version. Retrieved September 24, 2020.
- Jones, Adrian P., Frances Wall, and C. Terry Williams. Rare Earth Minerals: Chemistry, Origin and Ore Deposits. The Mineralogical Society Series. London, UK: Chapman and Hall, 1996. ISBN 0412610302 and ISBN 978-0412610301
- Stwertka, Albert. Guide to the Elements. Rev. ed. Oxford, UK: Oxford University Press, 1998. ISBN 0195080831
All links retrieved October 4, 2017.
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