Neodymium

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Neodymium,  60Nd
Neodymium2.jpg
Neodymium
Pronunciation /ˌnˈdɪmiəm/ (NEE-oh-DIM-ee-əm)
Appearancesilvery white
Standard atomic weight Ar, std(Nd)144.242(3) [1]
Neodymium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Nd

U
praseodymiumneodymiumpromethium
Atomic number (Z)60
Group group n/a
Period period 6
Block f-block
Element category   Lanthanide
Electron configuration [ Xe ] 4f4 6s2
Electrons per shell
2, 8, 18, 22, 8, 2
Physical properties
Phase at  STP solid
Melting point 1297  K (1024 °C,1875 °F)
Boiling point 3347 K(3074 °C,5565 °F)
Density (near r.t.)7.01 g/cm3
when liquid (at m.p.)6.89 g/cm3
Heat of fusion 7.14  kJ/mol
Heat of vaporization 289 kJ/mol
Molar heat capacity 27.45 J/(mol·K)
Vapor pressure
P (Pa)1101001 k10 k100 k
at T (K)159517741998(2296)(2715)(3336)
Atomic properties
Oxidation states 0, [2] +2, +3, +4 (a mildly basic oxide)
Electronegativity Pauling scale: 1.14
Ionization energies
  • 1st: 533.1 kJ/mol
  • 2nd: 1040 kJ/mol
  • 3rd: 2130 kJ/mol
Atomic radius empirical:181  pm
Covalent radius 201±6 pm
Color lines in a spectral range Neodymium spectrum visible.png
Color lines in a spectral range
Spectral lines of neodymium
Other properties
Natural occurrence primordial
Crystal structure double hexagonal close-packed (dhcp)
Hexagonal.svg
Speed of sound thin rod2330 m/s(at 20 °C)
Thermal expansion α, poly: 9.6 µm/(m·K)(at r.t.)
Thermal conductivity 16.5 W/(m·K)
Electrical resistivity α, poly: 643 nΩ·m
Magnetic ordering paramagnetic, antiferromagnetic below 20 K [3]
Magnetic susceptibility +5628.0·10−6 cm3/mol(287.7 K) [4]
Young's modulus α form: 41.4 GPa
Shear modulus α form: 16.3 GPa
Bulk modulus α form: 31.8 GPa
Poisson ratio α form: 0.281
Vickers hardness 345–745 MPa
Brinell hardness 265–700 MPa
CAS Number 7440-00-8
History
Discovery Carl Auer von Welsbach (1885)
Main isotopes of neodymium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
142Nd27.2% stable
143Nd12.2%stable
144Nd23.8%2.29×1015 yα 140Ce
145Nd8.3%stable
146Nd17.2%stable
148Nd5.8%2.7×1018 yββ 148Sm
150Nd5.6%21×1018 yββ 150Sm
| references

Neodymium is a chemical element with the symbol Nd and atomic number 60. Neodymium belongs to the lanthanide series and is a rare-earth element. It is a hard, slightly malleable silvery metal that quickly tarnishes in air and moisture. When oxidized, neodymium reacts quickly to produce pink, purple/blue and yellow compounds in the +2, +3 and +4 oxidation states. [5] 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 element, it is fairly common, no rarer than cobalt, nickel, or copper, and is widely distributed in the Earth's crust. [6] Most of the world's commercial neodymium is mined in China.

Chemical element a species of atoms having the same number of protons in the atomic nucleus

A chemical element is a species of atom having the same number of protons in their atomic nuclei. For example, the atomic number of oxygen is 8, so the element oxygen consists of all atoms which have 8 protons.

Symbol (chemistry) an arbitrary or conventional sign used in chemical science to represent a chemical element

In chemistry, a symbol is an abbreviation for a chemical element. Symbols for chemical elements normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalised.

Atomic number number of protons found in the nucleus of an atom

The atomic number or proton number of a chemical element is the number of protons found in the nucleus of every atom of that element. The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equal to the number of electrons.

Contents

Neodymium compounds were first commercially used as glass dyes in 1927, and they remain a popular additive in glasses. The color of neodymium compounds is due to the Nd3+ ion and 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 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.

Chemical compound Substance composed of multiple elements

A chemical compound is a chemical substance composed of many identical molecules composed of atoms from more than one element held together by chemical bonds. Two atoms of the same element bonded in a molecule do not form a chemical compound, since this would require two different elements.

Laser Device which emits light via optical amplification

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow.

Infrared electromagnetic radiation with longer wavelengths than those of visible light

Infrared radiation (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore generally invisible to the human eye, although IR at wavelengths up to 1050 nanometers (nm)s from specially pulsed lasers can be seen by humans under certain conditions. IR wavelengths extend from the nominal red edge of the visible spectrum at 700 nanometers, to 1 millimeter (300 GHz). Most of the thermal radiation emitted by objects near room temperature is infrared. As with all EMR, IR carries radiant energy and behaves both like a wave and like its quantum particle, the photon.

Neodymium is also used with various other substrate crystals, such as yttrium aluminium 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.

Substrate is a term used in materials science to describe the base material on which processing is conducted to produce new film or layers of material such as deposited coatings.

Yttrium aluminum garnet (YAG, Y3Al5O12) is a synthetic crystalline material of the garnet group. It is a cubic yttrium aluminum oxide phase, with other examples being YAlO3 in a hexagonal or an orthorhombic, perovskite-like form, and the monoclinic Y4Al2O9.

Nd:YAG laser

Nd:YAG (neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12) is a crystal that is used as a lasing medium for solid-state lasers. The dopant, triply ionized neodymium, Nd(III), typically replaces a small fraction (1%) of the yttrium ions in the host crystal structure of the yttrium aluminum garnet (YAG), since the two ions are of similar size. It is the neodymium ion which provides the lasing activity in the crystal, in the same fashion as red chromium ion in ruby lasers.

Another important use of neodymium is as a component in the alloys used to make high-strength neodymium magnets—powerful permanent magnets. [7] These magnets are widely used in such products as microphones, professional loudspeakers, in-ear headphones, high performance hobby DC electric motors, 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). [8]

Neodymium magnet type of magnet

A neodymium magnet (also known as NdFeB, NIB or Neo magnet), the most widely used type of rare-earth magnet, is a permanent magnet made from an alloy of neodymium, iron and boron to form the Nd2Fe14B tetragonal crystalline structure. Developed independently in 1982 by General Motors and Sumitomo Special Metals, neodymium magnets are the strongest type of permanent magnet commercially available. Due to different manufacturing processes, they are also divided into two subcategories, namely sintered NdFeB magnets and bonded NdFeB magnets. They have replaced other types of magnets in many applications in modern products that require strong permanent magnets, such as motors in cordless tools, hard disk drives and magnetic fasteners.

Electric motor electromechanical device

An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of rotation of a shaft. Electric motors can be powered by direct current (DC) sources, such as from batteries, motor vehicles or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters or electrical generators. An electric generator is mechanically identical to an electric motor, but operates in the reverse direction, converting mechanical energy into electrical energy.

Aircraft machine that is able to fly by gaining support from the air other than the reactions of the air against the earth’s surface

An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, helicopters, airships, gliders, paramotors and hot air balloons.

Characteristics

Physical properties

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, exposing the metal to further oxidation. Thus, a centimeter-sized sample of neodymium completely oxidizes within a year. [9]

Rare-earth element Any of the fifteen lanthanides plus scandium and yttrium

A rare-earth element (REE) or rare-earth metal (REM), as defined by the International Union of Pure and Applied Chemistry, is one of a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides, as well as scandium and yttrium. Scandium and yttrium are considered rare-earth elements because they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties, but have different electronic and magnetic properties. Rarely, a broader definition that includes actinides may be used, since the actinides share some mineralogical, chemical, and physical characteristics.

Metal element, compound, or alloy that is a good conductor of both electricity and heat

A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable or ductile. A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride.

Mischmetal

Mischmetal (from German: Mischmetall – "mixed metal") is an alloy of rare-earth elements. It is also called cerium mischmetal, or rare-earth mischmetal. A typical composition includes approximately 55% cerium, 25% lanthanum, and 15-18% neodymium with other rare earth metals following. Its most common use is in the pyrophoric ferrocerium "flint" ignition device of many lighters and torches, although an alloy of only rare-earth elements would be too soft to give good sparks. For this purpose, it is blended with iron oxide and magnesium oxide to form a harder material known as ferrocerium. In chemical formulae it is commonly abbreviated as Mm, e.g. MmNi5.

Neodymium commonly exists in two allotropic forms, with a transformation from a double hexagonal to a body-centered cubic structure taking place at about 863 °C. [10]

Allotropy Property of some chemical elements to exist in two or more different forms

Allotropy or allotropism is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements. Allotropes are different structural modifications of an element; the atoms of the element are bonded together in a different manner. For example, the allotropes of carbon include diamond, graphite, graphene, and fullerenes. The term allotropy is used for elements only, not for compounds. The more general term, used for any crystalline material, is polymorphism. Allotropy refers only to different forms of an element within the same phase ; differences in these states alone would not constitute examples of allotropy.

Neodymium is paramagnetic at room temperature, and becomes an antiferromagnet upon cooling to 20 K (−253.2 °C). [11] In order to make the neodymium magnets it is alloyed with iron, which is a ferromagnet.

Chemical properties

Neodymium metal quickly tarnishes at ambient conditions, [10] and readily burns at about 150 °C to form neodymium(III) oxide; the oxide peels off, exposing the bulk metal to the further oxidation [10]

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(III) hydroxide:

2 Nd (s) + 6 H2O (l) → 2 Nd(OH)3 (aq) + 3 H2 (g)

Neodymium metal reacts vigorously with all the halogens:

2 Nd (s) + 3 F2 (g) → 2 NdF3 (s) [a violet substance]
2 Nd (s) + 3 Cl2 (g) → 2 NdCl3 (s) [a mauve substance]
2 Nd (s) + 3 Br2 (g) → 2 NdBr3 (s) [a violet substance]
2 Nd (s) + 3 I2 (g) → 2 NdI3 (s) [a green substance]

Neodymium dissolves readily in dilute sulfuric acid to form solutions that contain the lilac Nd(III) ion. These exist as a [Nd(OH2)9]3+ complexes: [12]

2 Nd (s) + 3 H2SO4 (aq) → 2 Nd3+ (aq) + 3 SO2−
4
(aq) + 3 H2 (g)

Compounds

Neodymium compounds include

Neodymium(III)-sulfate Neodym(III)sulfat.JPG
Neodymium(III)-sulfate

Some neodymium compounds have colors that vary based upon the type of lighting.

Isotopes

Naturally occurring neodymium is a mixture of five stable isotopes, 142Nd, 143Nd, 145Nd, 146Nd and 148Nd, with 142Nd being the most abundant (27.2% of the natural abundance), and two radioisotopes, 144Nd and 150Nd. In all, 31 radioisotopes of neodymium have been detected as of 2010, with the most stable radioisotopes being the naturally occurring ones: 144Nd (alpha decay with a half-life (t1/2) of 2.29×1015 years) and 150Nd (double beta decay, t1/2 = 7×1018 years, approximately). All of the remaining radioactive isotopes have half-lives that are shorter than eleven days, and the majority of these have half-lives that are shorter than 70 seconds. Neodymium also has 13 known meta states, with the most stable one being 139mNd (t1/2 = 5.5 hours), 135mNd (t1/2 = 5.5 minutes) and 133m1Nd (t1/2 ~70 seconds).

The primary decay modes before the most abundant stable isotope, 142Nd, are electron capture and positron decay, 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.

History

Carl Auer von Welsbach (1858-1929), the discoverer of neodymium Auer von Welsbach.jpg
Carl Auer von Welsbach (1858–1929), the discoverer of neodymium

Neodymium was discovered by the Austrian chemist Carl Auer von Welsbach in Vienna in 1885. [13] [14] He separated neodymium, as well as the element praseodymium, from their mixture, called didymium, by means of fractional crystallization of the double ammonium nitrate tetrahydrates from nitric acid. Von Welsbach confirmed the separation by spectroscopic analysis, but the products were of relatively low purity. Didymium was discovered by Carl Gustaf Mosander in 1841, and pure neodymium was isolated from it in 1925. The name neodymium is derived from the Greek words neos (νέος), new, and didymos (διδύμος), twin. [10] [15] [16]

Double nitrate crystallization was the means of commercial neodymium purification until the 1950s. Lindsay Chemical Division was the first to commercialize large-scale ion-exchange purification of neodymium. Starting in the 1950s, high purity (above 99%) neodymium was primarily obtained through an ion exchange process from monazite, a mineral rich in rare-earth elements. [10] The metal itself is obtained through electrolysis of its halide salts. Currently, most neodymium is extracted from bastnäsite, (Ce,La,Nd,Pr)CO3F, and purified by solvent extraction. Ion-exchange purification is reserved for preparing the highest purities (typically >99.99%). The evolving technology, and improved purity of commercially available neodymium oxide, was reflected in the appearance of neodymium glass that resides in collections today. 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 manufacturing relied upon fractional crystallization technology.

Due to its role in permanent magnets used for direct-drive wind turbines, it has been argued[ citation needed ] that neodymium will be one of the main objects of geopolitical competition in a world running on renewable energy. This perspective has been criticised for failing to recognise that most wind turbines do not use permanent magnets, and for underestimating the power of economic incentives for expanded production. [17]

Occurrence and production

Bastnasite Bastnaesite - Kischtimsk, Ural.jpg
Bastnäsite

Neodymium is rarely found in nature as a free element, but rather it occurs in ores such as monazite and bastnäsite (these are mineral group names rather than single mineral names) that contain small amounts of all rare-earth metals. In these minerals neodymium is rarely dominant (as in the case of lanthanum), with cerium being the most abundant lanthanide; some exceptions include monazite-(Nd) and kozoite-(Nd). [18] The main mining areas are in China, the United States, Brazil, India, Sri Lanka, and Australia. The reserves of neodymium are estimated at about eight million tonnes. Although it belongs to the rare-earth metals, neodymium is not rare at all. Its abundance in the Earth's crust is about 38 mg/kg, which is the second highest among rare-earth elements, following cerium. The world's production of neodymium was about 7,000 tonnes in 2004. [15] The bulk of current production is from China. As of January 2010 the Chinese government has imposed strategic material controls on the element, raising some concerns in consuming countries and causing skyrocketing prices of neodymium and other rare-earth metals. [19] As of late 2011, 99% pure neodymium was traded in world markets for US$300 to US$350 per kilogram, down from the mid-2011 peak of US$500/kg. [20] The price of neodymium oxide fell from $200/kg in 2011 to $40 in 2015, largely due to illegal production in China which circumvented government restrictions. [21] The uncertainty of pricing and availability have caused companies (particularly Japanese ones) to create permanent magnets and associated electric motors with fewer rare-earth metals; however, so far they have been unable to eliminate the need for neodymium. [22] [23]

Neodymium is typically 10–18% of the rare-earth content of commercial deposits of the light rare-earth-element minerals bastnäsite and monazite. [10] With neodymium compounds being the most strongly colored for the trivalent lanthanides, it can occasionally dominate the coloration of rare-earth minerals when competing chromophores are absent. It usually gives a pink coloration. Outstanding examples of this include monazite crystals from the tin deposits in Llallagua, Bolivia; ancylite from Mont Saint-Hilaire, Quebec, Canada; or lanthanite from the Saucon Valley, Pennsylvania, United States. As with neodymium glasses, such minerals change their colors under the differing lighting conditions. The absorption bands of neodymium interact with the visible emission spectrum of mercury vapor, with the unfiltered shortwave UV light causing neodymium-containing minerals to reflect a distinctive green color. This can be observed with monazite-containing sands or bastnäsite-containing ore.

Applications

Magnets

Neodymium magnet on a mu-metal bracket from a hard drive Neodymag.jpg
Neodymium magnet on a mu-metal bracket from a hard drive

Neodymium magnets (actually an alloy, Nd2Fe14B) are the strongest permanent magnets known. A neodymium magnet of a few grams can lift a thousand times its own weight. These magnets are cheaper, lighter, and stronger than samarium–cobalt magnets. However, they are not superior in every aspect, as neodymium-based magnets lose their magnetism at lower temperatures and tend to rust, while samarium–cobalt magnets do not.

Neodymium magnets appear in products such as microphones, professional loudspeakers, in-ear headphones, guitar and bass guitar pick-ups, and computer hard disks where low mass, small volume, or strong magnetic fields are required. Neodymium magnet electric motors have also been responsible for the development of purely electrical model aircraft within the first decade of the 21st century, to the point that these are displacing internal combustion–powered models internationally.[ citation needed ] Likewise, due to this high magnetic capacity per weight, neodymium is used in the electric motors of hybrid and electric automobiles, and in the electricity generators of some designs of commercial wind turbines (only wind turbines with "permanent magnet" generators use neodymium). For example, drive electric motors of each Toyota Prius require one kilogram (2.2 pounds) of neodymium per vehicle. [8]

Neodymium doped lasers

Neodymium ions in various types of ionic crystals, and also in glasses, act as a laser gain medium, typically emitting 1064 nm light from a particular atomic transition in the neodymium ion, after being "pumped" into excitation from an external source YAG2.svg
Neodymium ions in various types of ionic crystals, and also in glasses, act as a laser gain medium, typically emitting 1064 nm light from a particular atomic transition in the neodymium ion, after being "pumped" into excitation from an external source
Neodymium doped glass slabs used in extremely powerful lasers for inertial confinement fusion. Laser glass slabs.jpg
Neodymium doped glass slabs used in extremely powerful lasers for inertial confinement fusion.
Nd:YAG laser rod Yag-rod.jpg
Nd:YAG laser rod

Certain transparent materials with a small concentration of neodymium ions can be used in lasers as gain media for infrared wavelengths (1054–1064 nm), e.g. Nd:YAG (yttrium aluminium garnet), Nd:YLF (yttrium lithium fluoride), Nd:YVO4 (yttrium orthovanadate), and Nd:glass. Neodymium-doped crystals (typically Nd:YVO4) generate high-powered infrared laser beams which are converted to green laser light in commercial DPSS hand-held lasers and laser pointers.

The current laser at the UK Atomic Weapons Establishment (AWE), the HELEN (High Energy Laser Embodying Neodymium) 1-terawatt neodymium-glass laser, can access the midpoints of pressure and temperature regions and is used to acquire data for modeling on how density, temperature, and pressure interact inside warheads. HELEN can create plasmas of around 106 K, from which opacity and transmission of radiation are measured. [28]

Neodymium glass solid-state lasers are used in extremely high power (terawatt scale), high energy (megajoules) multiple beam systems for inertial confinement fusion. Nd:glass lasers are usually frequency tripled to the third harmonic at 351 nm in laser fusion devices.

Neodymium glass for other applications

A neodymium glass light bulb, with the base and inner coating removed, under two different types of light: fluorescent on the left, and incandescent on the right. Neodymium glass light bulb under fluorescent and incandescent light.jpg
A neodymium glass light bulb, with the base and inner coating removed, under two different types of light: fluorescent on the left, and incandescent on the right.
Didymium glasses ACE Didymium Glasses RX-1205-BK Z87+.JPG
Didymium glasses

Neodymium glass (Nd:glass) is produced by the inclusion of neodymium oxide (Nd2O3) in the glass melt. Usually in daylight or incandescent light neodymium glass appears lavender, but it appears pale blue under fluorescent lighting. Neodymium may be used to color glass in delicate shades ranging from pure violet through wine-red and warm gray.

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. [29] Current sources include glassmakers in the Czech Republic, the United States, and China.

The sharp absorption bands of neodymium cause the glass color to change under different lighting conditions, being reddish-purple under daylight or yellow incandescent light, but blue under white fluorescent lighting, or greenish under trichromatic lighting. This color-change phenomenon is highly prized by collectors. In combination with gold or selenium, red colors are produced. Since neodymium coloration depends upon "forbidden" f-f transitions deep within the atom, there is relatively little influence on the color from the chemical environment, so the color is impervious to the thermal history of the glass. However, for the best color, iron-containing impurities need to be minimized in the silica used to make the glass. The same forbidden nature of the f-f transitions makes rare-earth colorants less intense than those provided by most d-transition elements, so more has to be used in a glass to achieve the desired color intensity. The original Moser recipe used about 5% of neodymium oxide in the glass melt, a sufficient quantity such that Moser referred to these as being "rare-earth doped" glasses. Being a strong base, that level of neodymium would have affected the melting properties of the glass, and the lime content of the glass might have had to be adjusted accordingly. [30]

Light transmitted through neodymium glasses shows unusually sharp absorption bands; the glass is used in astronomical work to produce sharp bands by which spectral lines may be calibrated. [10] Another application is the creation of selective astronomical filters to reduce the effect of light pollution from sodium and fluorescent lighting while passing other colours, especially dark red hydrogen-alpha emission from nebulae. [31] Neodymium is also used to remove the green color caused by iron contaminants from glass.

Neodymium is a component of "didymium" (referring to mixture of salts of neodymium and praseodymium) used for coloring glass to make welder's and glass-blower's goggles; the sharp absorption bands obliterate the strong sodium emission at 589 nm. The similar absorption of the yellow mercury emission line at 578 nm is the principal cause of the blue color observed for neodymium glass under traditional white-fluorescent lighting.

Neodymium and didymium glass are used in color-enhancing filters in indoor photography, particularly in filtering out the yellow hues from incandescent lighting.

Similarly, neodymium glass is becoming widely used more directly in incandescent light bulbs. These lamps contain neodymium in the glass to filter out yellow light, resulting in a whiter light which is more like sunlight. [32]

Similar to its use in glasses, neodymium salts are used as a colorant for enamels. [10]

Precautions

Neodymium
Hazards
GHS pictograms GHS-pictogram-exclam.svg
GHS Signal word Warning
H315, H319, H335
P261, P305+351+338 [33]
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeNeodymium
0
2
0

Neodymium metal dust is combustible and therefore an explosion hazard. Neodymium compounds, as with 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. [15]

Neodymium magnets have been tested for medical uses such as magnetic braces and bone repair, but biocompatibility issues have prevented widespread application. Commercially available magnets made from neodymium are exceptionally strong, and can attract each other from large distances. If not handled carefully, they come together very quickly and forcefully, causing injuries. For example, there is at least one documented case of a person losing a fingertip when two magnets he was using snapped together from 50 cm away. [34]

Another risk of these powerful magnets is that if more than one magnet is ingested, they can pinch soft tissues in the gastrointestinal tract. This has led to at least 1,700 emergency room visits and necessitated the recall of the Buckyballs line of toys, which were construction sets of small neodymium magnets. [35] [36]

Related Research Articles

Europium Chemical element with atomic number 63

Europium is a chemical element with the symbol Eu and atomic number 63. Europium is the most reactive lanthanide by far, having to be stored under an inert fluid to protect it from atmospheric oxygen or moisture. Europium is also the softest lanthanide, as it can be dented with a finger nail and easily cut with a knife. When oxidation is removed a shiny-white metal is visible. Europium was isolated in 1901 and is named after the continent of Europe. Being a typical member of the lanthanide series, europium usually assumes the oxidation state +3, but the oxidation state +2 is also common. All europium compounds with oxidation state +2 are slightly reducing. Europium has no significant biological role and is relatively non-toxic compared to other heavy metals. Most applications of europium exploit the phosphorescence of europium compounds. Europium is one of the rarest of the rare earth elements on Earth.

Erbium Chemical element with atomic number 68

Erbium is a chemical element with the symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare earth element, originally found in the gadolinite mine in Ytterby in Sweden, from which it got its name.

Holmium Chemical element with atomic number 67

Holmium is a chemical element with the symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a rare-earth element. Holmium was discovered by Swedish chemist Per Theodor Cleve. Its oxide was first isolated from rare-earth ores in 1878. The element's name comes from Holmia, the Latin name for the city of Stockholm.

Lanthanum Chemical element with atomic number 57

Lanthanum is a chemical element with the symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air and is soft enough to be cut with a knife. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. It is also sometimes considered the first element of the 6th-period transition metals, which would put it in group 3, although lutetium is sometimes placed in this position instead. Lanthanum is traditionally counted among the rare earth elements. The usual oxidation state is +3. Lanthanum has no biological role in humans but is essential to some bacteria. It is not particularly toxic to humans but does show some antimicrobial activity.

The lanthanide or lanthanoid series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare earth elements.

Samarium Chemical element with atomic number 62

Samarium is a chemical element with the symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air. Being a typical member of the lanthanide series, samarium usually assumes the oxidation state +3. Compounds of samarium(II) are also known, most notably the monoxide SmO, monochalcogenides SmS, SmSe and SmTe, as well as samarium(II) iodide. The last compound is a common reducing agent in chemical synthesis. Samarium has no significant biological role but is only slightly toxic.

Terbium Chemical element with atomic number 65

Terbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable, ductile, and soft enough to be cut with a knife. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, evolving hydrogen gas. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime, and euxenite.

Thulium Chemical element with atomic number 69

Thulium is a chemical element with the symbol Tm and atomic number 69. It is the thirteenth and third-last element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds; because it occurs so late in the series, however, the +2 oxidation state is also stabilized by the nearly full 4f shell that results. In aqueous solution, like compounds of other late lanthanides, soluble thulium compounds form coordination complexes with nine water molecules.

Ytterbium Chemical element with atomic number 70

Ytterbium is a chemical element with the symbol Yb and atomic number 70. It is the fourteenth and penultimate element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. However, like the other lanthanides, its most common oxidation state is +3, as in its oxide, halides, and other compounds. In aqueous solution, like compounds of other late lanthanides, soluble ytterbium compounds form complexes with nine water molecules. Because of its closed-shell electron configuration, its density and melting and boiling points differ significantly from those of most other lanthanides.

Monazite phosphate mineral series

Monazite is a reddish-brown phosphate mineral containing rare-earth metals. It occurs usually in small isolated crystals. It has a hardness of 5.0 to 5.5 on the Mohs scale of mineral hardness and is relatively dense, about 4.6 to 5.7 g/cm3. There are at least four different kinds of monazite, depending on relative elemental composition of the mineral:

Bastnäsite bastnäsite mineral series

The mineral bastnäsite (or bastnaesite) is one of a family of three carbonate-fluoride minerals, which includes bastnäsite-(Ce) with a formula of (Ce, La)CO3F, bastnäsite-(La) with a formula of (La, Ce)CO3F, and bastnäsite-(Y) with a formula of (Y, Ce)CO3F. Some of the bastnäsites contain OH instead of F and receive the name of hydroxylbastnasite. Most bastnäsite is bastnäsite-(Ce), and cerium is by far the most common of the rare earths in this class of minerals. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium and other rare-earth elements.

Praseodymium Chemical element with atomic number 59

Praseodymium is a chemical element with the symbol Pr and atomic number 59. It is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. Praseodymium is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.

Didymium chemical compound

Didymium is a mixture of the elements praseodymium and neodymium. It is used in safety glasses for glassblowing and blacksmithing, especially with a gas (propane)-powered forge, where it provides a filter that selectively blocks the yellowish light at 589 nm emitted by the hot sodium in the glass(references needed), without having a detrimental effect on general vision, unlike dark welder's glasses. The strong infrared light emitted by the superheated forge gases and insulation lining the forge walls is also blocked thereby saving the crafters' eyes from serious cumulative damage such as glassblower's cataract. The usefulness of didymium glass for eye protection of this sort was discovered by Sir William Crookes.

Neodymium(III) chloride or neodymium trichloride is a chemical compound of neodymium and chlorine with the formula NdCl3. This anhydrous compound is a mauve-colored solid that rapidly absorbs water on exposure to air to form a purple-colored hexahydrate, NdCl3·6H2O. Neodymium(III) chloride is produced from minerals monazite and bastnäsite using a complex multistage extraction process. The chloride has several important applications as an intermediate chemical for production of neodymium metal and neodymium-based lasers and optical fibers. Other applications include a catalyst in organic synthesis and in decomposition of waste water contamination, corrosion protection of aluminium and its alloys, and fluorescent labeling of organic molecules (DNA).

Holmium(III) oxide chemical compound

Holmium(III) oxide, or holmium oxide is a chemical compound of a rare-earth element holmium and oxygen with the formula Ho2O3. Together with dysprosium(III) oxide (Dy2O3) holmium oxide is one of the most powerfully paramagnetic substances known. The oxide, also called holmia, occurs as a component of the related erbium oxide mineral called erbia. Typically the oxides of the trivalent lanthanides coexist in nature and separation of these components requires specialized methods. Holmium oxide is used in making specialty colored glasses. Glass containing holmium oxide and holmium oxide solutions have a series of sharp optical absorption peaks in the visible spectral range. They are therefore traditionally used as a convenient calibration standard for optical spectrophotometers.

Neodymium(III) oxide chemical compound

Neodymium(III) oxide or neodymium sesquioxide is the chemical compound composed of neodymium and oxygen with the formula Nd2O3. It forms very light grayish-blue hexagonal crystals. The rare-earth mixture didymium, previously believed to be an element, partially consists of neodymium(III) oxide.

A dopant, also called a doping agent, is a trace of impurity element that is introduced into a chemical material to alter its original electrical or optical properties. The amount of dopant necessary to cause changes is typically very low. When doped into crystalline substances, the dopant's atoms get incorporated into its crystal lattice. The crystalline materials are frequently either crystals of a semiconductor such as silicon and germanium for use in solid-state electronics, or transparent crystals for use in the production of various laser types; however, in some cases of the latter, noncrystalline substances such as glass can also be doped with impurities.

Cerium Chemical element with atomic number 58

Cerium is a chemical element with the symbol Ce and atomic number 58. Cerium is a soft, ductile and silvery-white metal that tarnishes when exposed to air, and it is soft enough to be cut with a knife. Cerium is the second element in the lanthanide series, and while it often shows the +3 oxidation state characteristic of the series, it also exceptionally has a stable +4 state that does not oxidize water. It is also considered one of the rare-earth elements. Cerium has no biological role in humans and is not very toxic.

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