Neodymium (nee-o- dim-ee-əm) is a chemical element with the symbol "Nd" and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach. It is present in significant quantities in the ore minerals monazite and bastnäsite. Neodymium is not found naturally in metallic form or unmixed with other lanthanides, and it is usually refined for general use. Although neodymium is classed as a "rare earth", it is no rarer than cobalt, nickel, and copper ore, and is widely distributed in the Earth's crust. Most of the world's neodymium is mined in China. Neodymium compounds were first commercially used as glass dyes in 1927, and they remain a popular additive in glasses. The color of neodymium compounds—due to the Nd(III) ion—is often a reddish-purple but it changes with the type of lighting, due to fluorescent effects. Some neodymium-doped glasses are also used in lasers that emit infrared light with wavelengths between 1047 and 1062 nanometers. These have been used in extremely high power applications, such as experiments in inertial confinement fusion. Neodymium is also used with various other substrate crystals, such as yttrium aluminum garnet in the Nd:YAG laser. This laser usually emits infrared waves at a wavelength of about 1064 nanometers. The Nd:YAG laser is one of the most commonly used solid-state lasers. Another chief use of neodymium is as the free pure element. It is used as a component in the alloys used to make high-strength neodymium magnets – the most powerful permanent magnets known. These magnets are widely used in such products as microphones, professional loudspeakers, in-ear headphones, and computer hard disks, where low magnet mass or volume, or strong magnetic fields are required. Larger neodymium magnets are used in high power versus weight electric motors (for example in hybrid cars) and generators (for example aircraft and wind turbine electric generators). Neodymium, a rare earth metal, was present in the classical mischmetal at a concentration of about 18%. Metallic neodymium has a bright, silvery metallic luster, but as one of the more reactive lanthanide rare-earth metals, it quickly oxidizes in ordinary air. The oxide layer that forms then peels off, and this exposes the metal to further oxidation. Thus a centimeter-sized sample of neodymium completely oxidizes within a year. Neodymium exists in two allotropic forms, with a transformation from a double hexagonal to a body-centered cubic structure taking place at about 863 °C. Neodymium metal tarnishes slowly in air and it burns readily at about 150 °C to form the neodymium(III) oxide: 4 Nd + 3 O2 → 2 Nd2O3 Neodymium is a quite electropositive element, and it reacts slowly with cold water, but quite quickly with hot water to form neodymium hydroxide: 2 Nd (s) + 6 H2O (l) → 2 Nd(OH)3 (aq) + 3 H2 (g) Neodymium compounds include: halides: neodymium(III) fluoride – NdF3; neodymium(III) chloride – NdCl3; neodymium (III) bromide – NdBr3; neodymium(III) iodide – NdI3 oxides: Nd2O3 sulfides: neodymium(II) sulfide – NdS, neodymium(III) sulfide – Nd2S3 nitrides: neodymium(III) nitride – NdN hydroxide: neodymium hydroxide Nd(OH)3 phosphide: neodymium phosphide NdP carbide: neodymium carbide Nd4C3 nitrate: neodymium nitrate Nd(NO3)3 Naturally occurring neodymium is a mixture of five stable isotopes, 142Nd, 143Nd, 145Nd, 146Nd and 148Nd. Neodymium was discovered by Baron Carl 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 by means of fractional crystallization of the double ammonium nitrate tetrahydrates from nitric acid, while following the separation by spectroscopic analysis; however, it was not isolated in relatively pure form until 1925. The name neodymium is derived from the Greek words neos (νέος), new, and didymos (διδύμος), twin. Early neodymium glasses made in the 1930s have a more reddish or orange tinge than modern versions which are more cleanly purple, due to the difficulties in removing the last traces of praseodymium in the era when fractional crystallization technology had to be relied on. The first commercial use of purified neodymium was in glass coloration, starting with experiments by Leo Moser in November 1927. The resulting "Alexandrite" glass remains a signature color of the Moser glassworks to this day. Neodymium glass was widely emulated in the early 1930s by American glasshouses, most notably Heisey, Fostoria ("wisteria"), Cambridge ("heatherbloom"), and Steuben ("wisteria"), and elsewhere (e.g. Lalique, in France, or Murano). Tiffin's "twilight" remained in production from about 1950 to 1980. References: ^ Gschneidner, K. A.; Eyring, L. (1978). Handbook on the Physics and Chemistry of Rare Earths. Amsterdam: North Holland. ISBN 0444850228. ^ See Abundances of the elements (data page) ^ As hybrid cars gobble rare metals, shortage looms, Reuters, August 31, 2009. ^ "Rare-Earth Metal Long Term Air Exposure Test". Retrieved 2009-08-08. ^ C. R. Hammond (2000). The Elements, in Handbook of Chemistry and Physics 81st edition. CRC press. ISBN 0849304814. ^ "Chemical reactions of Neodymium". Webelements. Retrieved 2009-06-06. ^ John Emsley (2003). Nature's building blocks: an A-Z guide to the elements. Oxford University Press. pp. 268–270. ISBN 0198503407. ^ Concern as China clamps down on rare earth exports (The Independent, UK news site) ^ Y. Wei et al. "The Effect of Neodymium (Nd3+) on Some Physiological Activities in Oilseed Rape during Calcium (Ca2+) Starvation" 10th International Rapeseed Congress ^ "Team finds Earth's 'oldest rocks'". London: BBC news. 2008-09-26. Retrieved 2009- 06-06. ^ Norman, Michael J.; Andrew, James E.; Bett, Thomas H.; Clifford, Roger K.; England, John E.; Hopps, Nicholas W.; Parker, Kenneth W.; Porter, Kenneth; Stevenson, Mark (2002). "Multipass Reconfiguration of the HELEN Nd:Glass Laser at the Atomic Weapons Establishment". Applied Optics 41 (18): 3497– 505. Bibcode 2002ApOpt..41.3497N. doi:10.1364/AO.41.003497. PMID 12078672. ^ "Chameleon Glass Changes Color". Retrieved 2009-06-06.[dead link] ^ Charles Bray (2001). Dictionary of glass: materials and techniques. University of Pennsylvania Press. p. 102. ISBN 081223619X. ^ "History of Light, subheading "Timeline", 2001". Retrieved 2010-08-23. ^ Swain, Frank (March 6, 2009). "How to remove a finger with two super magnets". Seed Media Group LLC. Retrieved 2009-06-28. Other Books: "The Industrial Chemistry of the Lanthanons, Yttrium, Thorium and Uranium", by R.J. Callow, Pergamon Press 1967. Lindsay Chemical Division, American Potash and Chemical Corporation, Price List, 1960. "Chemistry of the Lanthanons", by R.C. Vickery, Butterworths 1953.