Neodymium

Neodymium is a chemical element in the periodic table that has the symbol Nd and atomic number 60.

Notable characteristics

Neodymium, a rare earth metal, is present in misch metal to the extent of about 18%. The metal has a bright silvery metallic luster; however, being one of the more reactive rare-earth metals, Neodymium quickly tarnishes in air, forming an oxide that spalls off and exposes the metal to further oxidation.

Applications

Uses of Neodymium include:

• Neodymium is a component of didymium[?] used for colouring glass to make welder's goggles
• Neodymium colours glass in delicate shades ranging from pure violet through wine-red and warm gray. Light transmitted through such glass shows unusually sharp absorption bands[?]; the glass is used in astronomical work to produce sharp bands by which spectral lines may be calibrated. Glass containing neodymium is a laser material in place of ruby to produce coherent light[?]. Neodymium is also used to remove the green colour caused by iron contaminants from glass.
• Neodymium salts are used as a colourant for enamels[?].
• Neodymium is used in very powerful permanent magnets - Nd₂Fe₁₄B[?]. These magnets are cheaper than Samarium-Cobalt magnets[?] .

History

Neodymium was discovered by Baron Carl F. Auer von Welsbach[?], an austrian chemist, in Vienna in 1885. He separated neodymium, as well as the element Praseodymium, from a material known as didymium[?]; however, it was not isolated in relatively pure form until 1925. The name Neodymium is derived from the greek words neos, new, and didymos, twin.

Today, Neodymium is primarily obtained from through an ion exchange process of monazite sand ((Ce,La,Th,Nd,Y)PO₄), a material rich in rare earth elements, and through electrolysis of its halide salts.

Biological role

Neodymium has no known biological role.

Occurrence

Neodymium is never found in nature as the free element; rather, it occurs in ores such as monazite sand ((Ce,La,Th,Nd,Y)PO₄) and bastnosite ((Ce,La,Th,Nd,Y)(CO₃)F) that contain small amounts of all the rare earth metals. Neodymium can also be found in Misch metal; it is difficult to separate from other rare earth elements.

Compounds

Neodymium compounds include:

• Fluorides
  • NdF₃[?]
• Chlorides
  • NdCl₂[?]
  • NdCl₃[?]
• Bromides
  • NdBr₂[?]
  • NdBrs₃[?]
• Iodides
  • NdI₂[?]
  • NdI₃[?]
• Oxides
  • Nd₂O₃[?]
• Sulfides
  • NdS[?]
  • Nd₂S₃[?]
• Selenides
  • NdSe[?]
• Tellurides
  • NdTe[?]
  • Nd₂Te₃[?]
• Nitrides
  • NdN[?]

Isotopes

Naturally occurring Neodymium is composed of 5 stable isotopes, 142-Nd, 143-Nd, 145-Nd, 146-Nd and 148-Nd, with 142-Nd being the most abundant (27.2% natural abundance), and 2 radioisotopes, 144-Nd and 150-Nd. 31 radioisotopes have been characterized, with the most stable being 150-Nd with a half-life of 1.1E19 years, 144-Nd with a half-life of 2.29E15 years, and 147-Nd with a half-life of 10.98 days. All of the remaining radioactive isotopes have half-lifes that are less than 3.38 days, and the majority of these have half lifes that are less than 71 seconds. This element also has 4 meta states with the most stable being 139m-Nd (t_½ 5.5 hours), 135m-Nd (t_½ 5.5 minutes) and 141m-Nd (t_½ 62.0 seconds).

The primary decay mode before the most abundant stable isotope, 142-Nd, is electron capture and the primary mode after is beta minus decay. The primary decay products before 142-Nd are element Pr (Praseodymium) isotopes and the primary products after are element Pm (Lead) isotopes.

Precautions

All Neodymium compounds should be regarded as highly toxic. Furthermore, Neodymium compounds are skin and eye irritants, and the metal dust presents a fire and explosion hazard.

External links

• WebElements.com - Neodymium (http://www.webelements.com/webelements/elements/text/Nnd/index)
• EnvironmentalChemistry.com - Neodymium (http://environmentalchemistry.com/yogi/periodic/Nd)
• It's Elemental - Neodymium (http://education.jlab.org/itselemental/ele060)