is a chemical element
with the symbol Dy
and atomic number
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.
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 ; 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.
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.
Dysprosium is never encountered as a free element, but is found in many minerals
, including xenotime
; often with erbium
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
Nearly all dysprosium compounds are in the +3 oxidation state, and are highly paramagnetic
. Holmium(III) oxide
) and Dysprosium(III) oxide (Dy2
) are the most powerfully paramagnetic
Dysprosium compounds include:
See also Dysprosium compounds.
Naturally occurring dysprosium is composed of 7 stable isotopes
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
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
1.257 minutes), 147m
55.7 seconds) and 145m
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.
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.