Dysprosium (Dy)

Stable isotopes of dysprosium available from ISOFLEX

Isotope Z(p) N(n) Atomic Mass Natural Abundance Enrichment Level Chemical Form
Dy-156  66  90  155.92428 0.06%  18.00-20.70%  Oxide
Dy-158  66  92  157.924405 0.10%  14.10-23.70%  Oxide
Dy-160 66 94 159.925194 2.34% 67.70-70.10% Oxide
Dy-161 66 95 160.926930 18.90% 92.20-93.50% Oxide
Dy-162 66 96 161.926795 25.50% >94.70% Oxide
Dy-163 66 97 162.928728 24.90% >94.50% Oxide
Dy-164 66 98 163.929171 28.20% 95.90-98.45% Oxide

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Dysprosium was discovered in 1886 by Paul-Émile Lecoq de Boisbaudran. Its name originates with the Greek word dysprositos, meaning “hard to obtain.”

Dysprosium is a silvery, noncorrosive metal with hexagonal crystals; the metal is soft enough to be cut with a knife, and it can be machined without sparking, if overheating is avoided. Dysprosium does not react with moist air to form hydroxide. It reacts slowly with water and halogen gases and is soluble in dilute acids. At ordinary temperatures, it is relatively stable in air; however, when heated with oxygen, it forms dysprosium sesquioxide. With halogens, it reacts slowly at room temperature, forming dysprosium trihalides. It combines with several nonmetals at high temperatures, forming binary compounds with varying compositions. It dissolves in most mineral acids, with the evolution of hydrogen.

Commercial applications of dysprosium include laser materials and commercial lighting; neutron-absorbing control rods in nuclear reactors; data storage applications such as hard disks; magnets for use in hybrid electric vehicle motors; use in dosimeters for measuring ionizing radiation; and metal-halide lamps.

In addition to being an explosion hazard (sparking fires that cannot be extinguished with water), dysprosium has low acute toxicity. Its soluble salts exhibit low toxicity in experimental animals when administered by intravenous route, with effects including degeneration of the liver and spleen.

Properties of Dysprosium

Name Dysprosium 
Symbol Dy 
Atomic number 66 
Atomic weight 162.50 
Standard state Solid at 298 ºK 
CAS Registry ID 7429-91-6 
Group in periodic table N/A 
Group name Lanthanoid 
Period in periodic table 6 (Lanthanoid) 
Block in periodic table f-block 
Color Silvery white 
Classification Metallic 
Melting point 1411 °C
Boiling point 2562 °C
Thermal conductivity 10.7 W/(m·K) at 298.2 ºK
Electrical resistivity 57.0 µΩ·cm at 25 ºC 
Electronegativity 1.22 
Specific heat 167 J/kg K 
Heat of vaporization 280 kJ·mol-1
Heat of fusion 11.1 kJ·mol-1
Density of liquid 8.37 g/cm3 at 1411 °C 
Density of solid 8.56 g/cm3 
Electron configuration [Xe]4f95d16s2 
Atomic volume 19.03 cm3/g atom 
Atomic radius 1.773 Å
Ionic radius 0.908 Å
Most common oxidation state +3 


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