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-Émile 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.

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 85^oK 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.

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_½ 1.257 minutes), 147m-Dy (t_½ 55.7 seconds) and 145m-Dy (t_½ 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.

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.