Difference between revisions of "Neodymium" - New World Encyclopedia
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== Occurrence == | == Occurrence == | ||
− | + | ||
+ | In nature, neodymium is found not as the free element but in ores such as [[monazite]] sand ((Ce,La,Th,Nd,Y)PO<sub>4</sub>) and [[bastnasite]] ((Ce,La,Th,Nd,Y)(CO<sub>3</sub>)F), which contain small amounts of various rare earth metals. Neodymium can also be found in [[Misch metal]], an alloy of rare earth elements in a range of naturally occurring proportions. It is difficult to separate neodymium from other rare earth elements. | ||
== History == | == History == | ||
Line 65: | Line 66: | ||
== Notable characteristics == | == Notable characteristics == | ||
− | Neodymium, a [[rare earth]] [[metal]], is present in [[Misch metal]] to the extent of about 18%. | + | Neodymium is an [[inner transition metal]] (or lanthanide) that lies in period 6 of the [[periodic table]], between [[praseodymium]] and [[promethium]]. Neodymium, a [[rare earth]] [[metal]], is present in [[Misch metal]] to the extent of about 18%. It has a bright, silvery metallic luster, but as one of the more reactive rare earth metals, it quickly tarnishes in air. The tarnishing forms an oxide layer that falls off, which exposes the metal to further oxidation. Although it belongs to "rare earth metals," neodymium is not rare at all. It constitutes 38 ppm of [[Earth]]’s crust. |
=== Isotopes === | === Isotopes === | ||
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== Applications == | == Applications == | ||
− | *Neodymium is a component of [[didymium]] used | + | *Neodymium is a component of [[didymium]]<ref>Didymium is a mixture of praseodymium and [[neodymium]].</ref> glass, which is used to make specialized goggles for [[welding|welder]]s and [[glass blowing|glass blower]]s. |
− | *Neodymium colors [[glass]] in delicate shades, ranging from pure violet through wine-red and warm | + | |
+ | *Neodymium colors [[glass]] in delicate shades, ranging from pure violet through wine-red and warm gray. Light transmitted through such glass shows unusually sharp [[absorption band]]s. The glass is used in [[astronomy|astronomical work]] to produce sharp bands by which [[spectral line]]s may be calibrated. Neodymium is also used to remove the green color caused by [[iron]] contaminants from glass. | ||
+ | |||
+ | [[Image:Laser_glass_slabs.jpg|thumb|right|300px|Neodymium doped glass slabs used in extremely powerful lasers for [[inertial confinement fusion]].]] | ||
+ | |||
*Neodymium salts are used as colorants for [[vitreous enamel|enamels]]. | *Neodymium salts are used as colorants for [[vitreous enamel|enamels]]. | ||
− | *Neodymium is used in the strongest permanent [[magnet]]s known | + | |
− | * | + | *Neodymium is used in the strongest permanent [[magnet]]s known: [[Neodymium magnet|Nd<sub>2</sub>Fe<sub>14</sub>B]]. These magnets are cheaper, lighter, and stronger than [[samarium-cobalt magnet]]s. Neodymium magnets appear in high-quality products such as [[microphone]]s, professional [[loudspeaker]]s, in-ear [[headphone]]s, and computer [[hard disk]]s, where low mass, small volume, or strong magnetic fields are required. |
− | * | + | |
− | *Certain transparent materials with a small concentration of neodymium [[ion]]s can be used in [[laser]]s as [[gain medium|gain media]] for infrared wavelengths (1054-1064 nm) | + | * Nd<sup>3+</sup> has been reported [http://www.regional.org.au/au/gcirc/2/399.htm] to promote plant growth, probably because of similarities to Ca<sup>2+</sup>. Compounds of rare earth elements are frequently used as [[fertilizer]]s in China. |
− | *Neodymium [[glass]] (Nd:Glass) [[solid-state laser]]s are used in extremely high power ([[1 E11 W#1 terawatt|terawatt]] scale), high energy ([[megajoule]]s) multiple beam systems for [[inertial confinement fusion]]. | + | |
− | + | * The size and strength of a volcanic eruption can be predicted by scanning for neodymium [[isotope|isotopes]]. The neodymium isotope composition of volcanic lava offers a gauge for the magnitude of a forthcoming volcanic eruption. Scientists can thus use this information to predict the size of an impending eruption and send a warning to residents of the area. | |
+ | |||
+ | *Certain transparent materials with a small concentration of neodymium [[ion]]s can be used in [[laser]]s as [[gain medium|gain media]] for infrared wavelengths (1054-1064 nm). Examples of these materials are neodymium-doped yttrium aluminum garnet ([[Nd:YAG laser|Nd:YAG]]), yttrium lithium fluoride ([[Neodymium-doped yttrium lithium fluoride|Nd:YLF]]), and yttrium orthovanadate ([[Neodymium-doped yttrium orthovanadate|Nd:YVO<sub>4</sub>]]). | ||
+ | |||
+ | *Neodymium [[glass]] (Nd:Glass) [[solid-state laser]]s are used in extremely high power ([[1 E11 W#1 terawatt|terawatt]] scale), high energy ([[megajoule]]s) multiple beam systems for [[inertial confinement fusion]]. | ||
== Precautions == | == Precautions == |
Revision as of 17:46, 22 February 2007
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General | |||||||||||||||||||||||||||||||||||||||||||||||||
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Name, Symbol, Number | neodymium, Nd, 60 | ||||||||||||||||||||||||||||||||||||||||||||||||
Chemical series | lanthanides | ||||||||||||||||||||||||||||||||||||||||||||||||
Group, Period, Block | n/a, 6, f | ||||||||||||||||||||||||||||||||||||||||||||||||
Appearance | silvery white, yellowish tinge | ||||||||||||||||||||||||||||||||||||||||||||||||
Atomic mass | 144.242(3) g/mol | ||||||||||||||||||||||||||||||||||||||||||||||||
Electron configuration | [Xe] 4f4 6s2 | ||||||||||||||||||||||||||||||||||||||||||||||||
Electrons per shell | 2, 8, 18, 22, 8, 2 | ||||||||||||||||||||||||||||||||||||||||||||||||
Physical properties | |||||||||||||||||||||||||||||||||||||||||||||||||
Phase | solid | ||||||||||||||||||||||||||||||||||||||||||||||||
Density (near r.t.) | 7.01 g/cm³ | ||||||||||||||||||||||||||||||||||||||||||||||||
Liquid density at m.p. | 6.89 g/cm³ | ||||||||||||||||||||||||||||||||||||||||||||||||
Melting point | 1297 K (1024 °C, 1875 °F) | ||||||||||||||||||||||||||||||||||||||||||||||||
Boiling point | 3347 K (3074 °C, 5565 °F) | ||||||||||||||||||||||||||||||||||||||||||||||||
Heat of fusion | 7.14 kJ/mol | ||||||||||||||||||||||||||||||||||||||||||||||||
Heat of vaporization | 289 kJ/mol | ||||||||||||||||||||||||||||||||||||||||||||||||
Heat capacity | (25 °C) 27.45 J/(mol·K) | ||||||||||||||||||||||||||||||||||||||||||||||||
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Atomic properties | |||||||||||||||||||||||||||||||||||||||||||||||||
Crystal structure | hexagonal | ||||||||||||||||||||||||||||||||||||||||||||||||
Oxidation states | 3 (mildly basic oxide) | ||||||||||||||||||||||||||||||||||||||||||||||||
Electronegativity | 1.14 (Pauling scale) | ||||||||||||||||||||||||||||||||||||||||||||||||
Ionization energies (more) |
1st: 533.1 kJ/mol | ||||||||||||||||||||||||||||||||||||||||||||||||
2nd: 1040 kJ/mol | |||||||||||||||||||||||||||||||||||||||||||||||||
3rd: 2130 kJ/mol | |||||||||||||||||||||||||||||||||||||||||||||||||
Atomic radius | 185 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
Atomic radius (calc.) | 206 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
Miscellaneous | |||||||||||||||||||||||||||||||||||||||||||||||||
Magnetic ordering | ferromagnetic | ||||||||||||||||||||||||||||||||||||||||||||||||
Electrical resistivity | (r.t.) (α, poly) 643 nΩ·m | ||||||||||||||||||||||||||||||||||||||||||||||||
Thermal conductivity | (300 K) 16.5 W/(m·K) | ||||||||||||||||||||||||||||||||||||||||||||||||
Thermal expansion | (r.t.) (α, poly) 9.6 µm/(m·K) | ||||||||||||||||||||||||||||||||||||||||||||||||
Speed of sound (thin rod) | (20 °C) 2330 m/s | ||||||||||||||||||||||||||||||||||||||||||||||||
Speed of sound (thin rod) | (r.t.) (α form) 41.4 m/s | ||||||||||||||||||||||||||||||||||||||||||||||||
Shear modulus | (α form) 16.3 GPa | ||||||||||||||||||||||||||||||||||||||||||||||||
Bulk modulus | (α form) 31.8 GPa | ||||||||||||||||||||||||||||||||||||||||||||||||
Poisson ratio | (α form) 0.281 | ||||||||||||||||||||||||||||||||||||||||||||||||
Vickers hardness | 343 MPa | ||||||||||||||||||||||||||||||||||||||||||||||||
Brinell hardness | 265 MPa | ||||||||||||||||||||||||||||||||||||||||||||||||
CAS registry number | 7440-00-8 | ||||||||||||||||||||||||||||||||||||||||||||||||
Notable isotopes | |||||||||||||||||||||||||||||||||||||||||||||||||
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Neodymium[1] (chemical symbol Nd, atomic number 60) is a silvery metallic element that is a member of the lanthanide series of chemical elements. It is considered one of the "rare earth metals."[2]
Occurrence
In nature, neodymium is found not as the free element but in ores such as monazite sand ((Ce,La,Th,Nd,Y)PO4) and bastnasite ((Ce,La,Th,Nd,Y)(CO3)F), which contain small amounts of various rare earth metals. Neodymium can also be found in Misch metal, an alloy of rare earth elements in a range of naturally occurring proportions. It is difficult to separate neodymium from other rare earth elements.
History
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 spectroscopic analysis; 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 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.
Notable characteristics
Neodymium is an inner transition metal (or lanthanide) that lies in period 6 of the periodic table, between praseodymium and promethium. Neodymium, a rare earth metal, is present in Misch metal to the extent of about 18%. It has a bright, silvery metallic luster, but as one of the more reactive rare earth metals, it quickly tarnishes in air. The tarnishing forms an oxide layer that falls off, which exposes the metal to further oxidation. Although it belongs to "rare earth metals," neodymium is not rare at all. It constitutes 38 ppm of Earth’s crust.
Isotopes
Naturally occurring Neodymium is composed of 5 stable isotopes, 142Nd, 143Nd, 145Nd, 146Nd and 148Nd, with 142Nd being the most abundant (27.2% natural abundance), and 2 radioisotopes, 144Nd and 150Nd. In all, 31 radioisotopes of Neodymium have been characterized, with the most stable being 150Nd with a half-life (T½) of >1.1×1019 years, 144Nd with a half-life of 2.29×1015 years, and 147Nd with a half-life of 10.98 days. All of the remaining radioactive isotopes have half-lives that are less than 3.38 days, and the majority of these have half-lives that are less than 71 seconds. This element also has 4 meta states with the most stable being 139Ndm (T½ 5.5 hours), 135Ndm (T½ 5.5 minutes) and 141Ndm (T½ 62.0 seconds).
The primary decay mode before the most abundant stable isotope, 142Nd, is electron capture and the primary mode after is beta minus decay. The primary decay products before 142Nd are element Pr (praseodymium) isotopes and the primary products after are element Pm (promethium) isotopes.
Compounds
Neodymium compounds include
See also neodymium compounds.
Applications
- Neodymium is a component of didymium[3] glass, which is used to make specialized goggles for welders and glass blowers.
- Neodymium colors 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. Neodymium is also used to remove the green color caused by iron contaminants from glass.
- Neodymium salts are used as colorants for enamels.
- Neodymium is used in the strongest permanent magnets known: Nd2Fe14B. These magnets are cheaper, lighter, and stronger than samarium-cobalt magnets. Neodymium magnets appear in high-quality products such as microphones, professional loudspeakers, in-ear headphones, and computer hard disks, where low mass, small volume, or strong magnetic fields are required.
- Nd3+ has been reported [1] to promote plant growth, probably because of similarities to Ca2+. Compounds of rare earth elements are frequently used as fertilizers in China.
- The size and strength of a volcanic eruption can be predicted by scanning for neodymium isotopes. The neodymium isotope composition of volcanic lava offers a gauge for the magnitude of a forthcoming volcanic eruption. Scientists can thus use this information to predict the size of an impending eruption and send a warning to residents of the area.
- Certain transparent materials with a small concentration of neodymium ions can be used in lasers as gain media for infrared wavelengths (1054-1064 nm). Examples of these materials are neodymium-doped yttrium aluminum garnet (Nd:YAG), yttrium lithium fluoride (Nd:YLF), and yttrium orthovanadate (Nd:YVO4).
- Neodymium glass (Nd:Glass) solid-state lasers are used in extremely high power (terawatt scale), high energy (megajoules) multiple beam systems for inertial confinement fusion.
Precautions
Neodymium metal dust is a combustion and explosion hazard.
Neodymium compounds, like all rare earth metals, are of low to moderate toxicity; however its toxicity has not been thoroughly investigated. Neodymium dust and salts are very irritating to the eyes and mucous membranes, and moderately irritating to skin. Breathing the dust can cause lung embolisms, and accumulated exposure damages the liver. Neodymium also acts as an anticoagulant, especially when given intravenously.
Neodymium magnets have been tested for medical uses such as magnetic braces and bone repair, but biocompatibility issues have prevented widespread application.
See also
- Chemical element
- Inner transition metal
- Metal
- Periodic table
- Neodymium magnet (NIB or NdFeB)
Footnotes
- ↑ Neodymium is frequently misspelled as neodynium.
- ↑ The term "rare earth metals" (or "rare earth elements") is a trivial name applied to 16 chemical elements: scandium, yttrium, and 14 of the 15 lanthanides (excluding promethium), which occur naturally on Earth. Some definitions also include the actinides. The word "earth" is an obsolete term for oxide. The term "rare earth" is discouraged by the International Union of Pure and Applied Chemistry (IUPAC), as these elements are relatively abundant in the Earth's crust.
- ↑ Didymium is a mixture of praseodymium and neodymium.
ReferencesISBN links support NWE through referral fees
- Neodymium Los Alamos National Laboratory. Retrieved February 20, 2007.
- Chang, Raymond (2006). Chemistry (ninth ed.) New York, NY: McGraw-Hill Science/Engineering/Math. ISBN 0073221031.
- Cotton, F. Albert; and Wilkinson, Geoffrey (1980). Advanced Inorganic Chemistry (4th ed.), New York, NY: Wiley. ISBN 0-471-02775-8.
- Greenwood, N.N.; and Earnshaw, A. (1998). Chemistry of the Elements (2nd Edition). Oxford, U.K.; Burlington, Massachusetts: Butterworth-Heinemann, Elsevier Science. ISBN 0750633654. Online version.
- Jones, Adrian P., Frances Wall, and C. Terry Williams (editors) (1996). Rare Earth Minerals: Chemistry, Origin and Ore Deposits (The Mineralogical Society Series). London, UK: Chapman and Hall. ISBN 0412610302 (ISBN-13: 978-0412610301).
- Stwertka, Albert (1998). Guide to the Elements, Revised Edition. Oxford, UK: Oxford University Press. ISBN 0-19-508083-1.
External links
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