Dysprosium

Notable 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 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.

Applications

Dysprosium is used, in conjunction with Vanadium and other elements, for making laser materials; its high thermal neutron absorption cross-section and melting point also suggest using it for nuclear control rods[?], and a Dysprosium oxide-Nickel cermet[?], which absorbs neutrons readily without swelling or contracting under prolonged neutron bombardment, is being used for cooling nuclear reactor rods[?]. Dysprosium-Cadmium chalcogenides[?] are sources of infrared radiation for studying chemical reactions; furthermore, Dysprosium is used for manufacturing compact discs.

History

Dysprosium was first identified in Paris in 1886 by French chemist Paul Émile Lecoq de Boisbaudran; 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 get at".

Biological role

Dysprosium does not have any known biological properties.

Occurrence

Dysprosium is never encountered as the free element, but is found in many minerals, including xenotime[?], fergusonite[?], gadolinite, euxenite, polycrase[?], blomstrandine[?], monazite and bastnasite, often with Erbium and Holmium or other rare earth elements.

Compounds

Dysprosium compounds include:

• Fluorides
  • DyF₃[?]
• Chlorides
  • DyCl₂[?]
  • DyCl₃[?]
• Bromides[?]
  • DyBr₂[?]
  • DyBr₃[?]
• Iodides[?]
  • DyI₂[?]
  • DyI₃[?]
• Oxides
  • Dy₂O₃[?]
• Sulfides[?]
  • 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_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 element Tb (Terbium) isotopes, and the primary products after are element Ho (Holmium) isotopes.

Precautions

All dysprosium compounds should be regarded as highly toxic. The metal dust presents a fire and explosion hazard.

External links

• WebElements.com - Dysprosium (http://www.webelements.com/webelements/elements/text/Dy/index)
• EnvironmentalChemistry.com - Dysprosium (http://environmentalchemistry.com/yogi/periodic/Dy)
• It's Elemental - Dysprosium (http://education.jlab.org/itselemental/ele066)