Dysprosium (CAS: 7429-91-6)

Dysprosium is a chemical element with the symbol Dy and atomic number 66.

It is a rare earth element with a metallic silver luster. Dysprosium is never found

in nature as a free element, though it is found in various minerals, such as xenotime.

Naturally occurring dysprosium is composed of 7isotopes, the most abundant of

which is 164Dy.

Dysprosium was first identified in 1886 by Paul Émile Lecoq de Boisbaudran, but was

not isolated in pure form until the development of ion exchangetechniques in the 1950s.

Dysprosium is used for its high thermal neutron absorption cross-section in making control

rods in nuclear reactors, for its high magnetic susceptibility in data storage applications, and

as a component of Terfenol-D. Soluble dysprosium salts are mildly toxic, while the insoluble

salts are considered non-toxic.

Chemical properties

Dysprosium metal tarnishes slowly in air and burns readily to form dysprosium(III) oxide:

4 Dy + 3 O2 → 2 Dy2O3

Dysprosium is quite electropositive and reacts slowly with cold water and quite quickly

with hot water to form dysprosium hydroxide:

2 Dy (s) + 6 H2O (l) → 2 Dy(OH)3 (aq) + 3 H2 (g)

Dysprosium metal vigorously reacts with all the halogens at above 200 °C:

2 Dy (s) + 3 F2 (g) → 2 DyF3 (s) [green]2 Dy (s) + 3 Cl2 (g) → 2 DyCl3 (s) [white]2 Dy

(s) + 3 Br2 (g) → 2 DyBr3 (s) [white]2 Dy (s) + 3 I2 (g) → 2 DyI3 (s) [green]

Dysprosium dissolves readily in dilute sulfuric acid to form solutions containing the yellow

Dy(III) ions, which exist as a [Dy(OH2)9]3+ complexes:[5]

2 Dy (s) + 3 H2SO4 (aq) → 2 Dy3+ (aq) + 3 SO4 2−(aq) + 3 H2 (g)

The resulting compound, dysprosium(III) sulfate, is noticeably paramagnetic.

Applications

Dysprosium is used, in conjunction with vanadium and other elements, in making laser materials

and commercial lighting. Because of dysprosium’s high thermal neutron absorption cross-section,

dysprosium oxide-nickel cermets are used in neutron-absorbing control rods in nuclear reactors.

Dysprosium-cadmium chalcogenides are sources of infrared radiation which is useful for studying

chemical reactions. Because dysprosium and its compounds are highly susceptible to magnetization,

they are employed in various data storage applications, such as in hard disks.

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 electric vehicles. This

substitution would require up to 100 grams of dysprosium per car produced. Based on Toyota’s

projected 2 million units per year, the use of dysprosium in applications such as this would quickly

exhaust the available supply of the metal. The dysprosium substitution may also be useful in other

applications, as it improves the corrosion resistance of the magnets.

Dysprosium is one of the components of Terfenol-D, along with iron and terbium. Terfenol-D has

the highest room-temperature magnetostriction of any known material; this property is employed

in transducers, wide-band mechanical resonators, and high-precision liquid fuel injectors.