Dysprosium

Dysprosium
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66 terbium ← dysprosium → holmium
-
↑
Dy
↓
Cf
Periodic Table - Extended Periodic Table


General
Name, Symbol, Number dysprosium, Dy, 66
Chemical series lanthanides
Group, Period, Block n/a, 6, f
Appearance silvery white

Standard atomic weight 162.500(1)  g·mol−1
Electron configuration [Xe] 4f10 6s2
Electrons per shell 2, 8, 18, 28, 8, 2
Physical properties
Phase solid
Density (near r.t.) 8.540  g·cm−3
Liquid density at m.p. 8.37  g·cm−3
Melting point 1680 K
(1407 °C, 2565 °F)
Boiling point 2840 K
(2562 °C, 4653 °F)
Heat of fusion 11.06  kJ·mol−1
Heat of vaporization 280  kJ·mol−1
Heat capacity (25 °C) 27.7  J·mol−1·K−1
Vapor pressure P(Pa) 1 10 100 1 k 10 k 100 k
at T(K) 1378 1523 (1704) (1954) (2304) (2831)

Atomic properties
Crystal structure hexagonal
Oxidation states 3
(weakly basic oxide)
Electronegativity 1.22 (scale Pauling)
Ionization energies
(more) 1st:  573.0  kJ·mol−1
2nd:  1130  kJ·mol−1
3rd:  2200  kJ·mol−1
Atomic radius 175  pm
Atomic radius (calc.) 228  pm
Miscellaneous
Magnetic ordering paramagnetic at r.t.,
ferromagnetic under
liquid nitrogen
Electrical resistivity (r.t.) (α, poly) 926 nΩ·m
Thermal conductivity (300 K) 10.7  W·m−1·K−1
Thermal expansion (r.t.) (α, poly)
9.9 µm/(m·K)
Speed of sound (thin rod) (20 °C) 2710 m/s
Young's modulus (α form) 61.4  GPa
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
Selected isotopes
Main article: Isotopes of dysprosium iso NA half-life DM DE (MeV) DP
154Dy syn 3.0×106y α 2.947 150Gd
156Dy 0.06% Dy is stable with 90 neutrons
158Dy 0.10% Dy is stable with 92 neutrons
160Dy 2.34% Dy is stable with 94 neutrons
161Dy 18.91% Dy is stable with 95 neutrons
162Dy 25.51% Dy is stable with 96 neutrons
163Dy 24.90% Dy is stable with 97 neutrons
164Dy 28.18% Dy is stable with 98 neutrons

References
Dysprosium (IPA: /dɪsˈprəʊziəm/) is a chemical element in the periodic table that has the symbol Dy and atomic number 66.

Contents [hide]
1 Notable characteristics
2 Applications
3 History
4 Occurrence
5 Compounds
6 Isotopes
7 Precautions
8 References
9 External links



[edit] Notable 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.


[edit] 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 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.

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 magenetomechanical 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.


[edit] History
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 δυσπροσιτος [dysprositos] = "hard to obtain". Part of the difficulty lay in dysprosium being especially close in its behavior to the far more abundant yttrium, during many of the separation technologies that were used in the 19th century. This overshadowed the fact that dysprosium was the most abundant of the heavy lanthanides.


[edit] Occurrence
Dysprosium is never encountered as a free element, but is found in many minerals, including xenotime, fergusonite, gadolinite, euxenite, polycrase, blomstrandine, monazite and bastnasite; 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).


[edit] 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 dysprosium compounds.


[edit] Isotopes
Main article: isotopes of dysprosium
Naturally occurring dysprosium is composed of 7 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% 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-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 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.


[edit] 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.


[edit] References
Los Alamos National Laboratory – Dysprosium

[edit] External links
Wikimedia Commons has media related to:
DysprosiumLook up dysprosium in
Wiktionary, the free dictionary.WebElements.com – Dysprosium
It's Elemental – Dysprosium
Retrieved from "http://en.wikipedia.org/wiki/Dysprosium"
Categories: Chemical elements | Lanthanides | Ferromagnetic materials