66
  Dy  
162.500000
Dysprosium

Name: Dysprosium
Symbol: Dy
Atomic Number: 66
Atomic Weight: 162.500000
Family:  Rare Earth Elements
CAS RN: 7429-91-6
Description: A soft silvery white rare earth metal.
State (25C): Solid
Oxidation states: +3

Molar Volume: 19 cm3/mole
Valence Electrons: 4f106s2

Boiling Point:  2835F, 2562C, 4644F
Melting Point:
1685K, 1412C, 2574F
Electrons Energy Level: 2, 8, 18, 28, 8, 2
Isotopes: 29 + 7 Stable + 4 meta states
Heat of Vaporization:  230 kJ/mol
Heat of Fusion: 11.06 kJ/mol
Density:  8.55 g/cm3 @ 300K
Specific Heat:  0.17 J/gK
Atomic Radius: 2.49
Ionic Radius: 0.912
Electronegativity: 1.22 (Pauling); 1.1 (Allrod Rochow)
57
La
138.9
58
Ce
140.1
59
Pr
140.9
60
Nd
144.2
61
Pm
(145)
62
Sm
150.4
63
Eu
152.0
64
Gd
157.3
65
Tb
158.9
66
Dy
162.5
67
Ho
164.9
68
Er
167.3
69
Tm
168.9
70
Yb
173.0
71
Lu
175.0

1s2 2s2p6 3s2p6d10 4s2p6d10f10 5s2p6 6s2

History

The Greek word dysprositos (hard to get at) gives some indication of the scarcity of dysprosium, but only to a degree.  It is about twice as abundant as uranium.  Dysprosium was discovered by Paul-mile Lecoq de Boisbaudran, a French chemist, in 1886 as an impurity in erbia, the oxide of erbium.  The metal was isolated by Georges Urbain, another French chemist, in 1906.  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 Greek (dysprositos): "hard to obtain".

Today, dysprosium is primarily obtained through an ion exchange process from monazite sand, (Ce, La, Th, Nd, Y)PO4, a material rich in rare earth elements. 

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.  The pure metal oxidizes readily in air.

1s2
2s2 2p6
3s2 3p6 3d10
4s2 4p6 4d10 4f10
5s2 5p6
6s2

Occurrence

Dysprosium occurs along with other so-called rare-earth or lanthanide elements in a variety of minerals such as xenotime, fergusonite, gadolinite, etivenite, polycrase, and blomstrandine.  The most important sources, however, are from monazite and bastnasite.  Dysprosium can be prepared by reduction of the trifluoride with calcium.  It is relatively stable in air at room temperature, and is readily attacked and dissolved, with the evolution of hydrogen, by dilute and concentrated mineral acids.  Small amounts of impurities can greatly affect its physical properties.  

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.

Below 85oK 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.

Compounds

Dysprosium oxide (Dy2O3), also known as dysprosia, is combined with nickel and added to a special cement used to cool nuclear reactor rods. Other dysprosium compounds include: dysprosium fluoride (DyF3), dysprosium iodide (DyI3) and dysprosium sulfate (Dy2(SO4)3).

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.

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

Isotopes

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 (t 1.257 minutes), 147m-Dy (t 55.7 seconds) and 145m-Dy (t 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.

atom.gif (700 bytes)

Isotope  
Atomic Mass
 
Half-Life
138Dy 137.96249 ~200 ms
139Dy 138.95954 600 ms
140Dy 139.95401 ~700 ms
141Dy 140.95135 0.9 s
142Dy 141.94637 2.3 s
143Dy 142.94383 5.6 s
143mDy   3.0 s
144Dy 143.93925 9.1 s
145Dy 144.93743 9.5 s
145mDy   14.1 s
146Dy 145.932845 33.2 s
147Dy 146.931092 40 s
147m1Dy   55 s
148Dy 147.927150 3.3 min
149Dy 148.927305 4.20 min
150Dy 149.925585 7.17 min
151Dy 150.926185 17.9 min
152Dy 151.924718 2.38 h
153Dy 152.925765 6.4 h
154Dy 153.924424 3.0 x 106 y
155Dy 154.925754 9.9 h
156Dy 155.924283 STABLE
157Dy 156.925466 8.14 h
158Dy 157.924409 STABLE
159Dy 158.9257392 144.4 d
160Dy 159.9251975 STABLE
161Dy 160.9269334 STABLE
162Dy 161.9267984 STABLE
163Dy 162.9287312 STABLE
164Dy 163.9291748 STABLE
165Dy 164.9317033 2.334 h
165mDy   1.257 min
166Dy 165.9328067 81.6 h
167Dy 166.93566 6.20 min
168Dy 167.93713 8.7 min
169Dy 168.94031 39 s
170Dy 169.94239 ~30 s
171Dy 170.94620 ~6 s
172Dy 171.94876 ~3 s
173Dy 172.95300 ~2 s

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.


atom.gif (700 bytes)

Dysprosium Data

 

Atomic Structure

Atomic Radius: 2.49
Atomic Volume: 19cm3/mol
Covalent Radius: 1.59
Crystal Structure: Hexagonal
Ionic Radius: 0.912

Chemical Properties

Electrochemical Equivalents: 2.021g/amp-hr
Electron Work Function:
Electronegativity: 1.22 (Pauling); 1.1 (Allrod Rochow)
Heat of Fusion: 11.06kJ/mol
First Ionization Potential: 5.94
Second Ionization Potential: 11.67
Third Ionization Potential: 22.802
Valence Electron Potential: 47.4 -eV
Ionization Energy: 5.939 eV

Physical Properties

Atomic Mass Average: 162.5
Boiling Point: 2835F, 2562C, 4644F
Melting Point: 1685K, 1412C, 2574F
Heat of Vaporization: 230kJ/mol
Coefficient of Lineal Thermal Expansion/K-1: 10E-6
Electrical Conductivity: 0.0108 106/cm
Thermal Conductivity: 0.107 W/cmK
Density: 8.55g/cm3 @ 300K
Enthalpy of Atomization: 301 kJ/mole @ 25C
Enthalpy of Fusion: 11.05 kJ/mole
Enthalpy of Vaporization: 230 kJ/mole
Molar Volume: 19 cm3/mole
Specific Heat: 0.17J/gK
Vapor Pressure: unknown
Estimated Crustal Abundance: 5.2 milligrams per kilogram
Estimated Oceanic Abundance: 9.110-7 milligrams per liter