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neodymium
Neodymium is a chemical element with 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 a fairly common element, no rarer than cobalt, nickel, and copper, and is widely distributed in the Earth's crust.〔See Abundances of the elements (data page)〕 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 Nd3+ ion—is often a reddish-purple but it changes with the type of lighting, due to the interaction of the sharp light absorption bands of neodymium with ambient light enriched with the sharp visible emission bands of mercury, trivalent europium or terbium. Some neodymium-doped glasses are also used in lasers that emit infrared 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 at a wavelength of about 1064 nanometers. The Nd:YAG laser is one of the most commonly used solid-state lasers.
Another important use of neodymium is as a component in the alloys used to make high-strength neodymium magnets—powerful permanent magnets.〔(Toshiba Develops Dysprosium-free Samarium-Cobalt Magnet to Replace Heat-resistant Neodymium Magnet in Essential Applications ). Toshiba (2012-08-16). Retrieved on 2012-09-24.〕 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).〔(As hybrid cars gobble rare metals, shortage looms ), Reuters, August 31, 2009.〕
==Characteristics==
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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