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Praseodymium is a chemical element that has the symbol Pr and atomic number 59. Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is too reactive to be found in native form, and when artificially prepared, it slowly develops a green oxide coating.Sony VAIO VPCY11V9E/S Battery

The element was named for the color of its primary oxide. In 1841, Swedish chemist Carl Gustav Mosander extracted a rare earth oxide residue he called "didymium" from a residue he called "lantana," in turn separted from cerium salts. In 1885, the Austrian chemist baron Carl Auer von Welsbach separated didymium into two salts of different colors,Sony VAIO VPCY218EC/BI Battery

which he named praseodymium and neodymium. The name praseodymium comes from the Greek prasios (???????), meaning green, and didymos(???????), twin.

Like most rare earth elements, praseodymium most readily forms trivalent Pr(III) ions.Sony VAIO VPCY218EC/G Battery

These are yellow-green in water solution, and various shades of yellow-green when incorporated into glasses. Many of praseodymium's industrial uses involve its use to filter yellow light from light sources.

Physical properties

Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group.Sony VAIO VPCY218EC/L Battery

It is somewhat more resistant tocorrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that spalls off when exposed to air, exposing more metal to oxidation — a centimeter-sized sample of Pr completely oxidizes within a year.Sony VAIO VPCY218EC/P Battery

For this reason, praseodymium is usually stored under a light mineral oil or sealed in glass.

Unlike other rare-earth metals, which show antiferromagnetic or/and ferromagnetic ordering at low temperatures, Pr isparamagnetic at any temperature above 1 K.Sony VAIO VPCY21S1E/L Battery

Chemical properties

Praseodymium metal tarnishes slowly in air and burns readily at 150 °C to form praseodymium(III,IV) oxide:

12 Pr + 11 O2 ? 2 Pr6O11

Praseodymium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form praseodymium hydroxide:Sony VAIO VPCY21S1E/P Battery

2 Pr (s) + 6 H2O (l) ? 2 Pr(OH)3 (aq) + 3 H2 (g)

Praseodymium metal reacts with all the halogens:

2 Pr (s) + 3 F2 (g) ? 2 PrF3 (s) [green]

2 Pr (s) + 3 Cl2 (g) ? 2 PrCl3 (s) [green]

2 Pr (s) + 3 Br2 (g) ? 2 PrBr3 (s) [green]

2 Pr (s) + 3 I2 (g) ? 2 PrI3 (s) [green]Sony VAIO VPCY21S1E/SI Battery

Praseodymium dissolves readily in dilute sulfuric acid to form solutions containing green Pr(III) ions, which exist as a [Pr(OH2)9]3+complexes:[4]

2 Pr (s) + 3 H2SO4 (aq) ? 2 Pr3+(aq) + 3 SO2?4 (aq) + 3 H2 (g)Sony VAIO VPCCW2S5C CN1 Battery

Compounds

In its compounds, praseodymium occurs in oxidation states +2, +3 and/or +4. Praseodymium(IV) is a strong oxidant, instantly oxidizing water to elemental oxygen (O2), or hydrochloric acid to elemental chlorine. Thus, in aqueous solution, only the +3 oxidation state is encountered.Sony VAIO VPCEA20 Battery

Praseodymium(III) salts are yellow-green and, in solution, present a fairly simple absorption spectrum in the visible region, with a band in the yellow-orange at 589–590 nm (which coincides with the sodium emission doublet), and three bands in the blue/violet region, at 444, 468, and 482 nm, approximately.Sony VAIO VPCEB10 Battery

These positions vary slightly with the counter-ion. Praseodymium oxide, as obtained by the ignition of salts such as the oxalate or carbonate in air, is essentially black in color (with a hint of brown or green) and contains +3 and +4 praseodymium in a somewhat variable ratio, depending upon the conditions of formation. Its formula is conventionally rendered as Pr6O11.Sony VAIO VPCEB11FM Battery

Other praseodymium compounds include:

  • Fluorides: PrF2, PrF3, PrF4
  • Chlorides: PrCl3
  • Bromides: PrBr3, Pr2Br5
  • Iodides: PrI2, PrI3, Pr2I5
  • Oxides: PrO2, Pr2O3, Pr6O11
  • Sulfides: PrS, Pr2S3
  • Sulfates: Pr2(SO4)3
  • Selenides: PrSe
  • Tellurides: PrTe, Pr2Te3
  • Nitrides: PrN  Sony VAIO VPCEB11FM/BI Battery

Naturally occurring praseodymium is composed of one stable isotope, praseodymium-141,[5] which is of use in NMR and EPR   spectroscopy.[6] 38 radioisotopes have been characterized, with the most stable being praseodymium-143 with a half-life of 13.57 days and praseodymium-142 with a half-life of 19.12 hours.Sony VAIO VPCEB11FM/T Battery

All of the remaining radioactive isotopes have half-lives that are less than six hours, and the majority of these have half lives that are less than 10 minutes.[5] This element also has 15 nuclear isomers, with the longest-lived being praseodymium-138m, praseodymium-134m, and praseodymium-142m .Sony VAIO VPCEB11FM/WI Battery

The nuclei of nuclear isomers exist in a delicate equilibrium or metastability due to at least one nucleon having an excited energy state.

The isotopes of praseodymium range in mass number from 121 to 159 .Sony VAIO VPCEB11FX Battery

The most common decay mode of 20 isotopes with mass numbers lower than the most abundant stable isotope, praseodymium-141 is beta+ decay, primarily forming cerium isotopes (58 protons) as decay products.[5] The most common decay mode for 18 isotopes with mass numbers higher than praseodymium-141 isbeta- decay, primarily forming neodymium isotopes (60 protons) as decay products.Sony VAIO VPCEB11FX/BI Battery

In 1839 Mosander extracted an oxide he called "lantana" (see lanthana), which was the oxide of the newly discovered elementlanthanum, from a mixture of crude cerium nitrate. In 1841, Mosander went on to show that "lantana" was the most strongly basic of a mixture of rare earth element oxides and precipitated from acid solution when base was added.Sony VAIO VPCEB11FX/T Battery

The remaining rare earth(s) remained in solution, and Mosander called these remainder salts "didymium." In 1874, Per Teodor Cleve concluded that didymium was in fact two elements, and in 1879, Lecoq de Boisbaudran isolated a new earth, samarium, from "didymium" obtained from the mineral samarskite.Sony VAIO VPCEB11FX/WI Battery

Crude didymium actually contained three elements, and in 1885, the Austrian chemistbaron Carl Auer von Welsbach separated didymium into two elements, praseodymium and neodymium, which gave salts of differentcolors.

The name praseodymium comes from the Greek prasios (???????), meaning green, and didymos (???????), twin. Praseodymium is frequently misspelled as praseodynium.Sony VAIO VPCEB11GX Battery

Leo Moser (son of Ludwig Moser, founder of the Moser Glassworks in what is now Karlovy Vary, Bohemia, in the Czech Republic, not to be confused with Leo Moser, a mathematician) investigated the use of praseodymium in glass coloration in the late 1920s. The result was a yellow-green glass given the name "Prasemit".Sony VAIO VPCEB11GX/BI Battery

However, a similar color could be achieved with colorants costing only a minute fraction of what praseodymium cost in the late 1920s, such that the color was not popular, few pieces were made, and examples are now extremely rare. Moser also blended praseodymium with neodymium to produce "Heliolite" glass ("Heliolit" in German), which was more widely accepted.Sony VAIO VPCEB11GX/T Battery

The first enduring commercial use of purified praseodymium, which continues today, is in the form of a yellow-orange stain for ceramics, "Praseodymium Yellow", which is a solid-solution of praseodymium in the zirconium silicate (zircon) lattice. This stain has no hint of green in it. By contrast, at sufficiently high loadings, praseodymium glass is distinctly green, rather than pure yellow.Sony VAIO VPCEB11GX/WI Battery

Using classical separation methods, praseodymium was always difficult to purify. Much less abundant than the lanthanum and neodymium from which it was being separated (cerium having long since been removed by redox chemistry), praseodymium ended up being dispersed among a large number of fractions, and the resulting yields of purified material were low.Sony VAIO VPCEB12FX Battery

Praseodymium has historically been a rare earth whose supply has exceeded demand. This has occasionally led to its being offered more cheaply than the far more abundant neodymium. Unwanted as such, much praseodymium has been marketed as a mixture with lanthanum and cerium, or "LCP" for the first letters of each of the constituents,Sony VAIO VPCEB12FX/BI Battery

for use in replacing the traditional lanthanide mixtures that were inexpensively made from monazite or bastnäsite. LCP is what remains of such mixtures, after the desirable neodymium, and all the heavier, rarer and more valuable lanthanides have been removed, by solvent extraction.Sony VAIO VPCEB12FX/BIC Battery

However, as technology progresses, it has been found that praseodymium can be incorporated into neodymium-iron-boron magnets, thereby extending the supply of the much in demand neodymium[citation needed]. So LC is starting to replace LCP as a result.Sony VAIO VPCEB12FX/T Battery

Occurrence

Praseodymium is available in small quantities in Earth's crust (9.5 ppm). It is found in the rare earth minerals monazite andbastnäsite, typically comprising about 5% of the lanthanides contained therein, and can be recovered from these minerals by anion exchange process, or by counter-current solvent extraction.Sony VAIO VPCEB14FX Battery

Misch metal, used in making cigarette lighters, contains about 5% praseodymium metal.

Applications

Uses of praseodymium:

  • Praseodymium forms the core of carbon arc lights which are used in the motion picture industry for studio lighting andprojector lights.
  • Praseodymium compounds give glasses and enamels a yellow color.
  • Praseodymium is used to color cubic zirconia yellow-green, to simulate the mineral peridot.Sony VAIO VPCEB14FX/T Battery
  • Praseodymium is a component of didymium glass, which is used to make certain types of welder's and glass blower's goggles.
  • Silicate crystals doped with praseodymium ions have been used to slow a light pulse down to a few hundred meters per second.Sony VAIO VPCEB14FX/WI Battery
  • Praseodymium alloyed with nickel (PrNi5) has such a strong magnetocaloric effect that it has allowed scientists to approach within one thousandth of a degree of absolute zero.
  • Doping praseodymium in fluoride glass allows it to be used as a single mode fiber optical amplifier.Sony VAIO VPCEB15FM Battery
  • Praseodymium oxide in solid solution with ceria, or with ceria-zirconia, have been used as oxidation catalysts.
  • Modern ferrocerium firesteel products, commonly referred to as "flint", used in lighters, torch strikers, "flint and steel" fire starters, etc., contain around 4% praseodymium.Sony VAIO VPCEB15FM/BI Battery

Neodymium 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.Sony VAIO VPCEB15FM/T Battery

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.[2]Most of the world's neodymium is mined in China.Sony VAIO VPCEB15FM/WI Battery

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.Sony VAIO VPCEB15FX Battery

Some neodymium-doped glasses are also used in lasers that emit infrared light with wavelengthsbetween 1047 and 1062 nanometers. These have been used in extremely high power applications, such as experiments ininertial confinement fusion.Sony VAIO VPCEB15FX/BI Battery

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.Sony VAIO VPCEB15FX/T Battery

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,Sony VAIO VPCEB15FX/WI Battery

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).Sony VAIO VPCEB16FX Battery

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.Sony VAIO VPCEB16FX/B Battery

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.Sony VAIO VPCEB16FX/G Battery

Chemical properties

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:Sony VAIO VPCEB16FX/L Battery

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

Neodymium metal reacts enthusiastically 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]Sony VAIO VPCEB16FX/P Battery

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:[6]

2 Nd (s) + 3 H2SO4 (aq) ? 2 Nd3+ (aq) + 3 SO2?
4 (aq) + 3 H2 (g)Sony VAIO VPCEB16FX/W Battery

Compounds

Neodymium compounds include

  • halides: neodymium(III) fluoride – NdF3;

neodymium(III) chloride – NdCl3; neodymium(III) bromide – NdBr3; neodymium(III) iodide – NdI3Sony VAIO VPCEB17FX Battery

  • 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 Sony VAIO VPCEB17FX/B Battery
  • carbide: neodymium carbide Nd4C3
  • nitrate: neodymium nitrate Nd(NO3)3

And many more, since neodymium is a quite reactive element

Some neodymium compounds have colors which vary based upon the type of lighting.Sony VAIO VPCEB17FX/G Battery

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:Sony VAIO VPCEB17FX/L Battery

144Nd (alpha decay with a half-life (T½) of 2.29×1015 years) and 150Nd (double beta decay, T½ = 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.Sony VAIO VPCEB17FX/P Battery

Neodymium also has 13 known meta states, with the most stable one being139mNd (T½ = 5.5 hours), 135mNd (T½ = 5.5 minutes) and 133m1Nd (T½ ~ 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.Sony VAIO VPCEB17FX/W Battery

The primary decay products before 142Nd are element Pr (praseodymium) isotopes and the primary products after are element Pm (promethium) isotopes.

Neodymium was discovered by Baron Carl Auer von Welsbach, an Austrian chemist, in Vienna in 1885.Sony VAIO VPCEB190X Battery

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 byspectroscopic analysis; however, it was not isolated in relatively pure form until 1925.Sony VAIO VPCEB19FX Battery

The name neodymium is derived from the Greek words neos (????), new, anddidymos (???????), twin.

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.Sony VAIO VPCEB19GX Battery

Starting in the 1950s, high purity (above 99%) neodymium was primarily obtained through an ion exchange process frommonazite, a mineral rich in rare earth elements. 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.Sony VAIO VPCEB1AFX Battery

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.Sony VAIO VPCEB1AFX/B Battery

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.Sony VAIO VPCEB1AGX Battery

Occurrence and production

Neodymium is never found in nature as the free element, but rather it occurs in ores such as monazite and bastnäsite that contain small amounts of all the rare earth metals. The main mining areas are in China, the United States, Brazil, India, Sri Lanka, and Australia.Sony VAIO VPCEB1AGX/BI Battery

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 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.Sony VAIO VPCEB1BGX Battery

The bulk of current production is from China, whose government has recently imposed strategic materials controls on the element, raising some concerns in consuming countries.

Neodymium is typically 10% to 18% of the rare earth content of commercial deposits of the light rare earth element minerals bastnasite and monazite.Sony VAIO VPCEB1BGX/BI Battery

With neodymium compounds being the most strongly colored for the trivalent lanthanides, that percentage of neodymium can occasionally dominate the coloration of rare earth minerals—when competing chromophores are absent. It usually gives a pink coloration.Sony VAIO VPCEB1CGX Battery

Outstanding examples of this include monazite crystals from the tin deposits in Llallagua, Bolivia, ancylite from Mont Saint-Hilaire, Quebec, or lanthanite from the Saucon Valley, Pennsylvania. As with neodymium glasses, such minerals change their colors under the differing lighting conditions.Sony VAIO VPCEB1CGX/BI Battery

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 bastnasite-containing ore.Sony VAIO VPCEB1DGX Battery

Applications

  • Neodymium has an unusually large specific heat capacity at liquid-helium temperatures, so is useful in cryocoolers
  • Probably because of similarities to Ca2+, Nd3+ has been reported to promote plant growth. Rare earth element compounds are frequently used in China asfertilizer.Sony VAIO VPCEB1DGX/BI Battery
  • Samarium-neodymium dating is useful for determining the age relationships of rocks and meteorites.
  • Size and strength of volcanic eruption can be predicted by scanning for neodymium isotopes. Small and large volcanic eruptions produce lava with different neodymium isotope composition.Sony VAIO VPCEB1EGX Battery
  • From the composition of isotopes, scientists predict how big the coming eruption will be, and use this information to warn residents of the intensity of the eruption.

Magnets

Neodymium magnets are the strongest permanent magnets known – Nd2Fe14B.Sony VAIO VPCEB1EGX/BI Battery

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 all ways, as neodymium-based magnets lose their magnetism at high temperatures and tend to rust, while samarium-cobalt magnets do not.Sony VAIO VPCEB1FGX Battery

Neodymium magnets appear in products such as microphones, professional loudspeakers, in-ear headphones, guitar and bass guitarpick-ups and computer hard disks where low mass, small volume, or strong magnetic fields are required.Sony VAIO VPCEB1FGX/BI Battery

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. Likewise, due to this high magnetic capacity per weight, neodymium is used in the electric motors of hybrid and electric automobiles,Sony VAIO VPCEB1GGX Battery

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.Sony VAIO VPCEB1GGX/BI Battery

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.Sony VAIO VPCEB1HGX Battery

Certain transparent materials with a small concentration of neodymiumions 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.Sony VAIO VPCEB1HGX/BI Battery

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,Sony VAIO VPCEB1JFX Battery

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.Sony VAIO VPCEB1JFX/B Battery

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.Sony VAIO VPCEB1JFX/G Battery

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 (Nd:glass) is produced by the inclusion of neodymium oxide (Nd2O3) in the glass melt.Sony VAIO VPCEB1JFX/L Battery

Usually in daylight orincandescent 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.Sony VAIO VPCEB1JFX/P Battery

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).Sony VAIO VPCEB1JFX/W Battery

Tiffin's "twilight" remained in production from about 1950 to 1980. 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,Sony VAIO VPCEB1KGX Battery

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, beautiful red colors result.Sony VAIO VPCEB1KGX/B Battery

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. Sony VAIO VPCEB1KGX/W Battery

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.Sony VAIO VPCEB1LFX Battery

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.

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.Sony VAIO VPCEB1LFX/BI Battery

Neodymium is also used to remove the green color caused by ironcontaminants 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.Sony VAIO VPCEB1LFX/WI Battery

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.Sony VAIO VPCEB1MFX Battery

Neodymium has been patented for use in automobile rear-view mirrors, to reduce the glare at night.

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

Precautions

Neodymium metal dust is a combustion and explosion hazard. Neodymium compounds, as with all rare earth metals, are of low to moderate toxicity; however its toxicity has not been thoroughly investigated.Sony VAIO VPCEB1MFX/BI Battery

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.Sony VAIO VPCEB1NFX Battery

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.Sony VAIO VPCEB1NFX/B Battery

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.

Promethium is a chemical element with the symbol Pm and atomic number 61.Sony VAIO VPCEB1NFX/L Battery

It is notable for being the only exclusively radioactive element besides technetium that is followed by chemical elements with stable isotopes.

Prediction

The existence of promethium was first predicted by Bohuslav Brauner in 1902.Sony VAIO VPCEB1NFX/P Battery

During his research on the chemical properties of rare earth elements he found that the difference between neodymium and samarium is larger than between the otherlanthanides. This prediction was supported in 1914 by Henry Moseley who, having discovered that atomic number was an experimentally measurable property of elements, found that no known element had atomic number 61.Sony VAIO VPCEB1NFX/W Battery

With the knowledge of a gap in the periodic table several groups started to search for the predicted element among other rare earths in the natural environment.

Florentium and Illinium

The first claim of a discovery was published by Italian scientists Luigi Rolla and Lorenzo Fernandes from Florence.Sony VAIO VPCEB1PFX Battery

After separating a didymium nitrate concentrate from the Brazilian mineral monazite by fractionated crystallisation, they yielded a solution containing mostly samarium. This solution gave x-ray spectra attributed to samarium and element 61. In honor of their city they named element 61 Florentium.Sony VAIO VPCEB1PFX/B Battery

The results were published in 1926, but the scientists claimed that the experiments were done in 1924. ]

Also in 1926, a group of scientists from the University of Illinois at Urbana-Champaign, Smith Hopkins and Len Yntema published the discovery of element 61. They named it illinium, after the university.Sony VAIO VPCEB1QGX Battery

Both of these reported discoveries are now known to be erroneous because there are no stable or long-lived isotopes of promethium, hence there was none to be found in these sources.

True promethium

Promethium was first produced and characterized at Oak Ridge National Laboratory (ORNL) in 1945 by Jacob A. Marinsky,Sony VAIO VPCEB1QGX/BI Battery

Lawrence E. Glendenin and Charles D. Coryell by separation and analysis of the fission products of uranium fuel irradiated in the Graphite Reactor; however, being too busy with military-related research during World War II, they did not announce their discovery until 1947.Sony VAIO VPCEB1RGX Battery

The name promethium is derived from Prometheus, the Titan, in Greek mythology, who stole fire from Mount Olympus and brought it down to mankind. The name was suggested by Grace Mary Coryell, Charles Coryell's wife, who felt that they were stealing fire from the gods.Sony VAIO VPCEB1RGX/BI Battery

In 1963, ion-exchange methods were used at ORNL to prepare about ten grams of promethium from nuclear reactor fuel processing wastes.

Today, promethium is still recovered from the byproducts of uranium fission; it can also be produced by bombarding 146Nd withneutrons, turning it into 147Nd which decays into 147Pm through beta decay with a half-life of 11 days.Sony VAIO VPCEB20 Battery

Occurrence

Promethium can be formed in nature as a product of spontaneous fission of uranium-238 andalpha decay of europium-151. Only trace amounts can be found in naturally occurring ores: a sample of pitchblende has been found to contain promethium at a concentration of four parts per quintillion (1018) by mass.Sony VAIO VPCEC20 Battery

It was calculated that the equilibrium mass of promethium in the Earth's crust is about 560g due to uranium fission and about 12g due to the recently observed alpha decay of europium-151.

Promethium has also been identified in the spectrum of the star HR 465 in Andromeda, and possibly HD 101065 (Przybylski's star) and HD 965.Sony VAIO VPCEE20 Battery

Characteristics

Promethium is the only lanthanide and one of two elements among the first 82 that has no stable (or even long-lived) isotopes; this is a result of a rarely occurring effect of the liquid drop model and stabilities of neighbor element isotopes. The most stable isotope of the element is promethium-145, which has a half-life of 17.7 years.Sony VAIO VPCEF20 Battery

In other words, if a kilogram of pure promethium-145 could be created at a moment, only about 20 grams would be left after 100 years. Promethium is also the least stable element of the first 84. The primary decay products are neodymium and samariumisotopes (promethium-146 decays to both, the lighter generally to neodymium, and heavier to samarium).Sony VAIO VPCF112FX/B Battery

Exact promethium isotopes may decay to praseodymium or other promethium isotopes (in case of nuclear isomers).

Promethium is a lanthanide metal whose chemical properties mostly resemble those of other lanthanides. The melting point of the element was claimed to have been calculated to be around 1042 °C (1908 °F, 1315 K),Sony VAIO VPCF115FG/B Battery

well suiting in the general trend of its increase with atomic numbers in lanthanides. Pure promethium exists in two allotropic forms, and its chemistry is similar to other lanthanides. Promethium salts luminesce in the dark with a pale blue or greenish glow, due to their high radioactivity.Sony VAIO VPCF116FGBI Battery

Chemical properties

Promethium metals tarnish slowly in air and burns readily at 150 °C to form promethium oxide:

4 Pm + 3 O2 ? 2 Pm2O3

Promethium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form promethium hydroxide:Sony VAIO VPCF117FJ/W Battery

2 Pm (s) + 6 H2O (l) ? 2 Pm(OH)3 (aq) + 3 H2 (g)

Promethium metal reacts with all the halogens:

2 Pm (s) + 3 F2 (g) ? 2 PmF3 (s)

2 Pm (s) + 3 Cl2 (g) ? 2 PmCl3 (s)

2 Pm (s) + 3 Br2 (g) ? 2 PmBr3 (s)

2 Pm (s) + 3 I2 (g) ? 2 PmI3 (s)

Promethium(III) iodide may also be synthesized by reacting PmX3 (X = Cl, Br) with hydrogen iodide at 400  °C:Sony VAIO VPCF117HG/BI Battery

2 PmX3(s) + 3HI(g) ? PmI3(s) + 3HX(g)

Promethium dissolves readily in dilute sulfuric acid to form solutions containing the pink Pm(III) ions, which exist as a [Pm(OH2)9]3+ complexes:

2 Pm(s) + 3 H2SO4 (aq) ? 2 Pm3+ (aq) + 3 (SO4)2- (aq) + 3 H2 (g)

Promethium(III) ions form an insoluble, hygroscopic oxalate when dissolved in aqueous H2C2O4:Sony VAIO VPCF118FJ/W Battery

2 Pm3+(aq) + C2O42- (aq) ? Pm2(C2O4)3•xH2O(s)

Applications

Uses for promethium include:

  • As a beta radiation source for thickness gauges.
  • As a light source for signals that require reliable, independent operation (using phosphor to absorb the beta radiation and produce light).Sony VAIO VPCF119FC Battery
  • In particular, Promethium(III) chloride (PmCl3) mixed with zinc sulfide (ZnS) was used for a time as a major luminous paint for watches after radium was discontinued. This mixture is still occasionally used for some luminous paint applications (though most such uses requiring radioactive materials have switched to tritium for safety reasons).Sony VAIO VPCF119FC/BI Battery
  • In an atomic battery in which cells convert the beta emissions into electric current, yielding a useful life of about five years, usingPm-147.
  • Promethium has possible future uses in portable X-ray sources, and as auxiliary heat or power sources for space probes and satellites (although the alpha emitter plutonium-238 has become standard for most space-exploration related uses – see Radioisotope thermoelectric generators).Sony VAIO VPCF119FJ/BI Battery

]Precautions

Promethium must be handled with great care because of its high radioactivity. In particular, promethium can emit X-rays during its beta decay. It is expected to have biological toxicity comparable with beta emitters of similar half-life, for example iodine-131.Sony VAIO VPCF11AFJ Battery

It is not as hazardous as alpha emitters such as the transuranics, due to the far lower relative biological effectiveness of beta emitters over alpha emitters. Promethium has no biological role.

Samarium is a chemical element with the symbol Sm, atomic number 62 and atomic weight 150.36.Sony VAIO VPCF11AGJ Battery

It is a moderately hard silvery metal which readily 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 monoxide SmO,monochalcogenides SmS, SmSe and SmTe, as well as samarium(II) iodide.Sony VAIO VPCF11AHJ Battery

The last compound is a common reducing agent inchemical synthesis. Samarium has no significant biological role and is only slightly toxic.

Samarium was discovered in 1879 by the French chemist Paul Émile Lecoq de Boisbaudran and named after the mineral samarskitefrom which it was isolated.Sony VAIO VPCF11JFX/B Battery

The mineral itself was earlier named after a Russian mine official, Colonel Vasili Samarsky-Bykhovets, who thereby became the first person to have a chemical element named after him, albeit indirectly. Although classified as a rare earth element, samarium is the 40th most abundant element in the Earth's crust and is more common than such metals as tin.Sony VAIO VPCF11M1E Battery

Samarium occurs with concentration up to 2.8% in several minerals including cerite, gadolinite,samarskite, monazite and bastnäsite, the last two being the most common commercial sources of the element. These minerals are mostly found in China, the USA, Brazil, India, Sri Lanka and Australia; China is by far the world leader in samarium mining and production.Sony VAIO VPCF11M1E/H Battery

The major commercial application of samarium is in samarium-cobalt magnets which have permanent magnetization second only toneodymium magnets; however, samarium compounds can withstand significantly higher temperatures, above 700 °C, without losing their magnetic properties.Sony VAIO VPCF11MFX/B Battery

Radioactive isotope samarium-153 is the major component of the drug samarium (153Sm) lexidronam(Quadramet) which kills cancer cells in the treatment of lung cancer, prostate cancer, breast cancer and osteosarcoma. Another isotope, samarium-149, is a strong neutron absorber and is therefore added to the control rods of nuclear reactors.Sony VAIO VPCF11S1E Battery

It is also formed as a decay product during the reactor operation and is one of the important factors considered in the reactor design and operation. Other applications of samarium include catalysis of chemical reactions, radioactive dating and an X-ray laser.

Physical properties

Samarium is a rare earth metal having the hardness and density similar to those of zinc.Sony VAIO VPCF11S1E/B Battery

With the boiling point of 1794 °C, samarium is the third most volatile lanthanide after ytterbium and europium; this property facilitates separation of samarium from the mineral ore. At ambient conditions, samarium normally assumes a trigonal structure (? form).-sony-vaio-vpcf11z1e-battery-27486.htm" title="Sony VAIO VPCF11Z1E laptop battery">Sony VAIO VPCF11Z1E Battery

Upon heating to 731 °C, its crystal symmetry changes into hexagonal close-packed (hcp), however the transition temperature depends on the metal purity. Further heating to 922 °C transforms the metal into a body-centered cubic (bcc) phase. Heating to 300 °C combined with compression to 40 kbar results in a double-hexagonal close-packed structure (dhcp).Sony VAIO VPCF11Z1E/BI Battery

Applying higher pressure of the order of hundreds or thousands of kilobars induces a series of phase transformations, in particular with a tetragonal phase appearing at about 900 kbar. In one study, the dhcp phase could be produced without compression, using a nonequilibrium annealing regime with a rapid temperature change between about 400 and 700 °C, confirming the transient character of this samarium phase. Sony VAIO VPCF11ZHJ Battery

Also, thin films of samarium obtained by vapor deposition may contain the hcp or dhcp phases at ambient conditions.

Samarium (and its sesquioxide) are paramagnetic at room temperature. Their corresponding effective magnetic moments, below 2µB, are the 3rd lowest among the lanthanides (and their oxides) after lanthanum and lutetium. The metal transforms to anantiferromagnetic state upon cooling to 14.8 K.Sony VAIO VPCF127HGBI Battery

Individual samarium atoms can be isolated by encapsulating them intofullerene molecules.They can also be doped between the C60molecules in the fullerene solid, rendering it superconductiveat temperatures below 8 K. Samarium doping of iron-based superconductors –Sony VAIO VPCF127HGBI Battery

the most recent class of high-temperature superconductors – allows to enhance their transition temperature to 56 K, which is the highest value achieved so far in this series.

Chemical properties

Freshly prepared samarium has a silvery luster. In air, it slowly oxidizes at room temperature and spontaneously ignites at 150 °C.Sony VAIO VPCF137HG/BI Battery

Even when stored under mineral oil, samarium gradually oxidizes and develops a grayish-yellow powder of theoxide-hydroxide mixture at the surface. The metallic appearance of a sample can be preserved by sealing it under an inert gas such as argon.

Samarium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form samarium hydroxide:Sony VAIO VPC-P111KX/B Battery

2 Sm (s) + 6 H2O (l) ? 2 Sm(OH)3 (aq) + 3 H2 (g)

Samarium dissolves readily in dilute sulfuric acid to form solutions containing the yellow to pale green Sm(III) ions, which exist as [Sm(OH2)9]3+ complexes: 2 Sm (s) + 3 H2SO4 (aq) ? 2 Sm3+ (aq) + 3 SO2?4 (aq) + 3 H2 (g)

Samarium is one of the few lanthanides that exhibit the oxidation state +2. The Sm2+ ions are blood-red in solutions.Sony VAIO VPC-P111KX/D Battery

Oxides

The most stable oxide of samarium is the sesquioxide Sm2O3. As many other samarium compounds, it exists in several crystalline phases. The trigonal form is obtained by slow cooling from the melt.Sony VAIO VPC-P111KX/G Battery

The melting point of Sm2O3 is rather high (2345 °C) and therefore melting is usually achieved not by direct heating, but with induction heating, through a radio-frequency coil. The Sm2O3 crystals of monoclinic symmetry can be grown by the flame fusion method (Verneuil process) from the Sm2O3 powder,Sony VAIO VPC-P111KX/P Battery

that yields cylindrical boules up to several centimeters long and about one centimeter in diameter. The boules are transparent when pure and defect-free and are orange otherwise. Heating the metastable trigonal Sm2O3 to 1900 °C converts it to the more stable monoclinic phase. Cubic Sm2O3 has also been described.Sony VAIO VPC-P111KX/W Battery

Samarium is one of the few lanthanides that form a monoxide, SmO. This lustrous golden-yellow compound was obtained by reducing Sm2O3 with samarium metal at elevated temperature (1000 °C) and pressure above 50 kbar; lowering the pressure resulted in an incomplete reaction. SmO has the cubic rock-salt lattice structure.Sony VAIO VPC-P112KX/B Battery

Chalcogenides

Samarium forms trivalent sulfide, selenide and telluride. Divalent chalcogenides SmS, SmSe and SmTe with cubic rock-salt crystal structure are also known. They are remarkable by converting from semiconducting to metallic state at room temperature upon application of pressure.Sony VAIO VPC-P112KX/D Battery

Whereas the transition is continuous and occurs at about 20–30 kbar in SmSe and SmTe, it is abrupt in SmS and requires only 6.5 kbar. This effect results in spectacular color change in SmS from black to golden yellow when its crystals of films are scratched or polished.Sony VAIO VPC-P112KX/G Battery

The transition does not change lattice symmetry, but there is a sharp decrease (~15%) in the crystal volume.[35] It shows hysteresis, that is when the pressure is released, SmS returns to the semiconducting state at much lower pressure of about 0.4 kbar.[8][36]

Halides

Samarium metal reacts with all the halogens X = F, Cl, Br or I, forming trihalides:Sony VAIO VPC-P112KX/P Battery

2 Sm (s) + 3 X2 (g) ? 2 SmX3 (s)

Their further reduction with samarium, lithium or sodium metals at elevated temperatures (about 700–900 °C) yields dihalides.[27]The diiodide can also be prepared by heating SmI3, or by reacting the metal with 1,2-diiodoethane in anhydrous tetrahydrofuran at room temperature:Sony VAIO VPC-P112KX/W Battery

Sm (s) + ICH2-CH2I ? SmI2 + CH2=CH2

In addition to dihalides, the reduction also produces numerous non-stoichiometric samarium halides with a well-defined crystal structure, such as Sm3F7, Sm14F33, Sm27F64,[26] Sm11Br24, Sm5Br11 and Sm6Br13Sony VAIO VPCP113KX/B Battery

As reflected in the table above, samarium halides change their crystal structures when one type of halide atoms is substituted for another, which is an uncommon behavior for most elements (e. g. actinides). Many halides have two major crystal phases for one composition, one being significantly more stable and another being metastable.Sony VAIO VPC-P113KX/B Battery

The latter is formed upon compression or heating, followed by quenching to ambient conditions. For example, compressing the usual monoclinic samarium diiodide and releasing the pressure results in a PbCl2-type orthorhombic structure (density 5.90 g/cm3), and similar treatment results in a new phase of samarium triiodide (density 5.97 g/cm3).Sony VAIO VPCP113KX/D Battery

Borides

Sintering powders of samarium oxide and boron, in vacuum, yields a powder containing several samarium boride phases, and their volume ratio can be controlled through the mixing proportion.Sony VAIO VPC-P113KX/D Battery

The powder can be converted into larger crystals of a certain samarium boride using arc melting or zone melting techniques, relying on the different melting/crystallization temperature of SmB6 (2580 °C), SmB4 (about 2300 °C) and SmB66 (2150 °C). All these materials are hard, brittle, dark-gray solids with the hardness increasing with the boron content.Sony VAIO VPCP113KX/G Battery

Samarium diboride is too volatile to be produced with these methods and requires high pressure (about 65 kbar) and low temperatures between 1140 and 1240 °C to stabilize its growth. Increasing the temperature results in the preferential formations of SmB6.Sony VAIO VPC-P113KX/G Battery

Samarium hexaboride is a typical intermediate-valence compound where samarium is present both as Sm2+ and Sm3+ ions at the ratio 3:7. It belongs to a class ofKondo insulators, that is at high temperatures (above 50 K), its properties are typical of a Kondo metal, with metallic electrical conductivity characterized by strong electron scattering, whereas at low temperatures, it behaves as a non-magnetic insulator with a narrow band gap of about 4–14 meV.Sony VAIO VPCP118JC/B Battery

The cooling-induced metal-insulator transition in SmB6 is accompanied by a sharp increase in the thermal conductivity, peaking at about 15 K. The reason for this increase is that electrons themselves do not contribute to the thermal conductivity at low temperatures, which is dominated by phonons, but the decrease in electron concentration reduced the rate of electron-phonon scattering.Sony VAIO VPCP118JC/P Battery

Other inorganic compounds

Samarium carbides are prepared by melting a graphite-metal mixture in an inert atmosphere. After the synthesis, they are unstable in air and are studied also under inert atmosphere. Samarium monophosphide SmP is a semiconductor with the bandgap of 1.10 eV, the same as in silicon, and high electrical conductivity of n-type.Sony VAIO VPCP118JC/W Battery

It can be prepared by annealing at 1100 °C an evacuated quartz ampoule containing mixed powders of phosphorus and samarium. Phosphorus is highly volatile at high temperatures and may explode, thus the heating rate has to be kept well below 1 °C/min. Similar procedure is adopted for the monarsenide SmAs, but the synthesis temperature is higher at 1800 °C.Sony VAIO VPC-P118KX/B Battery

A large number of crystalline binary compounds are known for samarium and one of the group-4, 5 or 6 element X, where X is Si, Ge, Sn, Pb, Sb or Te, and metallic alloys of samarium form another large group. They are all prepared by annealing mixed powders of the corresponding elements.Sony VAIO VPC-P118KX/D Battery

Many of the resulting compounds are non-stoichiometric and have nominal compositions SmaXb, where the b/a ratio varies between 0.5 and 3.

Organometallic compounds

Samarium forms a cyclopentadienide Sm(C5H5)3 and its chloroderivatives Sm(C5H5)2Cl and Sm(C5H5)Cl2.Sony VAIO VPC-P118KX/G Battery

They are prepared by reacting samarium trichloride with NaC5H5 intetrahydrofuran. Contrary to cyclopentadienides of most other lanthanides, in Sm(C5H5)3 some C5H5 rings bridge each other by forming ring vertexes ?1 or edges ?2toward another neighboring samarium atom, thereby creating polymeric chains.Sony VAIO VPC-P118KX/P Battery

The chloroderivative Sm(C5H5)2Cl has a dimer structure which is more accurately expressed as (?5-C5H5)2Sm(µ-Cl)2(?5-C5H5)2. There, the chlorine bridges can be replaced, for instance, by iodine, hydrogen or nitrogen atoms or by CN groups.

The (C5H5)– ion in samarium cyclopentadienides can be replaced by the indenide (C9H7)– or cyclooctatetraenide (C8H8)2– ring, resulting in Sm(C9H7)3 or KSm(?8-C8H8)2.Sony VAIO VPC-P118KX/W Battery

The latter compound has a similar structure to that of uranocene. There is also a cyclopentadienide of divalent samarium, Sm(C5H5)2 – a solid which sublimates at about 85 °C. Contrary to ferrocene, the C5H5 rings in Sm(C5H5)2 are not parallel but are tilted by 40°.Sony VAIO VPCP119JC Battery

Alkyls and aryls of samarium are obtained through a metathesis reaction in tetrahydrofuran or ether:[48]

SmCl3 + 3 LiR ? SmR3 + 3 LiCl

Sm(OR)3 + 3 LiCH(SiMe3)2 ? Sm{CH(SiMe3)2}3 + 3 LiOR

Here R is a hydrocarbon group and Me stands for methyl.Sony VAIO VPCP119JC/BI Battery

Naturally occurring samarium has a radioactivity of 128 Bq/g. It is composed of four stable isotopes: 144Sm, 150Sm, 152Sm and 154Sm, and three extremely long-livedradioisotopes, 147Sm (half-life t½ = 1.06×1011 years), 148Sm (7×1015 years) and 149Sm (>2×1015 years), with 152Sm being the most abundant (natural abundance26.75%).Sony VAIO VPCP11S1E/B Battery

149Sm is listed by various sources either as stable  or radioactive isotope.[52]

The long-lived isotopes,146Sm, 147Sm, and 148Sm, primarily decay by emission of alpha particles to isotopes of neodymium. Lighter unstable isotopes of samarium primarily decay by electron capture to isotopes of promethium, while heavier ones convert through beta decay to isotopes of europium.Sony VAIO VPC-P11S1E/B Battery

The alpha-decay of 147Sm to 143Nd with a half-life of 1.06×1011 years serve for samarium-neodymium dating

The half-lives of 151Sm and 145Sm are 90 years and 340 days, respectively. All of the remaining radioisotopes have half-lives that are less than 2 days, and the majority of these have half-lives that are less than 48 seconds.Sony VAIO VPCP11S1E/D Battery

Samarium also has five nuclear isomers with the most stable being 141mSm (half-life 22.6 minutes),143m1Sm (t½ = 66 seconds) and 139mSm (t½ = 10.7 seconds).

Detection of samarium and related elements was announced by several scientists in the second half of the 19th century; Sony VAIO VPC-P11S1E/D Battery

however, most sources give the priority to the French chemist Paul Émile Lecoq de Boisbaudran.[53][54] Boisbaudran isolated samarium oxide and/or hydroxide in Paris in 1879 from the mineral samarskite ((Y,Ce,U,Fe)3(Nb,Ta,Ti)5O16) and identified a new element in it via sharp optical absorption lines.Sony VAIO VPCP11S1E/G Battery

The Swiss chemist Marc Delafontaine announced a new element decipium (from Latin: decipiens meaning "deceptive, misleading") in 1878, but later in 1880–1881 demonstrated that it was a mixture of several elements, one being identical to the Boisbaudran's samarium.Sony VAIO VPC-P11S1E/G Battery

Although samarskite was first found in the remote Russian region of Urals, by the late 1870s its deposits had been located in other places making the mineral available to many researchers. In particular, it was found that the samarium isolated by Boisbaudran was also impure and contained comparable amount of europium.Sony VAIO VPCP11S1E/P Battery

The pure element was produced only in 1901 byEugène-Anatole Demarçay.

Boisbaudran named his element samaria after the mineral samarskite, which in turn honored Vasili Samarsky-Bykhovets (1803–1870). Samarsky-Bykhovets was the Chief of Staff of the Russian Corps of Mining Engineers who granted access for the German mineralogists, brothers Gustav Rose and Heinrich Rose, to study the mineral samples from the Urals.Sony VAIO VPCP11S1E/W Battery

In this sense samarium was the first chemical element to be named after a person. Later the name samaria used by Boisbaudran was transformed into samarium, to conform with other element names, and samaria nowadays is sometimes used to refer to samarium oxide, by analogy with yttria, zirconia, alumina,ceria, holmia, etc.Sony VAIO VPC-P11S1E/W Battery

The symbol Sm was suggested for samarium; however an alternative Sa was frequently used instead until the 1920s.

Prior to the advent of ion-exchange separation technology in the 1950s, samarium had no commercial uses in pure form.Sony VAIO VPCP11Z9E/B Battery

However, a by-product of the fractional crystallization purification of neodymium was a mixture of samarium and gadolinium that acquired the name of "Lindsay Mix" after the company that made it. This material is thought to have been used for nuclear control rods in some of the early nuclear reactors.Sony VAIO VPCS111FM/S Battery

Nowadays, a similar commodity product has the name "samarium-europium-gadolinium" (SEG) concentrate.[63] It is prepared by solvent extraction from the mixed lanthanides isolated from bastnäsite (or monazite). Since the heavier lanthanides have the greater affinity for the solvent used, they are easily extracted from the bulk using relatively small proportions of solvent.Sony VAIO VPCS115EC Battery

Not all rare earth producers who process bastnäsite do so on large enough scale to continue onward with the separation of the components of SEG, which typically makes up only one or two percent of the original ore. Such producers will therefore be making SEG with a view to marketing it to the specialized processors.Sony VAIO VPCS115FG Battery

In this manner, the valuable europium content of the ore is rescued for use in phosphor manufacture. Samarium purification follows the removal of the europium. Currently, being in oversupply, samarium oxide is less expensive on a commercial scale than its relative abundance in the ore might suggest.Sony VAIO VPCS117GG Battery

Occurrence and production

With the average concentration of about 8 parts per million (ppm), samarium is the 40th most abundant element in the Earth's crust. It is the fifth most abundant lanthanide and is more common than such element as tin. Samarium concentration in soils varies between 2 and 23 ppm, and oceans contain about 0.5–0.8 parts per trillion.Sony VAIO VPCS117GGB Battery

Distribution of samarium in soils strongly depends on its chemical state and is very inhomogeneous: in sandy soils, samarium concentration is about 200 times higher at the surface of soil particles than in the water trapped between them, and this ratio can exceed 1,000 in clays.Sony VAIO VPCS118EC Battery

Samarium is not found free in nature, but, like other rare earth elements, is contained in many minerals, including monazite,bastnäsite, cerite, gadolinite and samarskite; monazite (in which samarium occurs at concentrations of up to 2.8%)[9] and bastnäsite are mostly used as commercial sources.Sony VAIO VPCS119FJ/B Battery

World resources of samarium are estimated at two million tonnes; they are mostly located in China, US, Brazil, India, Sri Lanka and Australia, and the annual production is about 700 tonnes. Country production reports are usually given for all rare-earth metals combined.Sony VAIO VPCS119GC Battery

By far, China has the largest production with 120,000 tonnes mined per year; it is followed by the US (about 5,000 tonnes)[66] and India (2,700 tonnes). Samarium is usually sold as oxide, which at the price of about 30 USD/kg is one of the cheapest lanthanide oxides.Sony VAIO VPCS11AFJ Battery

Whereas mischmetal – a mixture of rare earth metals containing about 1% of samarium – has long been used, relatively pure samarium has been isolated only recently, through ion exchange processes, solvent extraction techniques, andelectrochemical deposition.Sony VAIO VPCS11AGJ Battery

The metal is often prepared by electrolysis of a molten mixture of samarium(III) chloride with sodium chloride or calcium chloride. Samarium can also be obtained by reducing its oxide with lanthanum. The product is then distilled to separate samarium (boiling point 1794 °C) and lanthanum (b. p. 3464 °C).Sony VAIO VPCS11AHJ Battery

Samarium-151 is produced in nuclear fission of uranium with the yield of about 0.4% of the total number of fission events. It is also synthesized upon neutron capture by samarium-149, which is added to the control rods of nuclear reactors. Consequently, samarium-151 is present in spent nuclear fuel and radioactive waste.Sony VAIO VPCS11AVJ Battery

Applications

One of the most important applications of samarium is in samarium-cobalt magnets, which have a nominal composition of SmCo5 or Sm2Co17. They have high permanent magnetization, which is about 10,000 times that of iron and is second only to that of neodymium magnets.Sony VAIO VPCS11J7E/B Battery

However, samarium-based magnets have higher resistance to demagnetization, as they are stable to temperatures above 700 °C (cf. 300–400 °C for neodymium magnets). These magnets are found in small motors, headphones, high-end magnetic pickups for guitars and related musical instruments.Sony VAIO VPCS11M1E/W Battery

For example, they are used in the motors of a solar-powered electric aircraft Solar Challenger and in the Samarium Cobalt Noiseless electric guitar and bass pickups.

Another important application of samarium and its compounds is as catalyst and chemical reagent.Sony VAIO VPCS11V9E Battery

Samarium catalysts assist decomposition of plastics, dechlorination of pollutants such as polychlorinated biphenyls (PCBs), as well as the dehydration anddehydrogenation of ethanol. Samarium(III) triflate (Sm(OTf)3, that is Sm(CF3SO3)3) is one of the most efficient Lewis acidcatalysts for a halogen-promoted Friedel–Crafts reaction with alkenes.Sony VAIO VPCS11V9E/B Battery

Samarium(II) iodide is a very common reducing and coupling agent in organic synthesis, for example in the desulfonylation reactions; annulation; Danishefsky, Kuwajima, Mukaiyamaand Holton Taxol total syntheses; strychnine total synthesis; Barbier reaction and other reductions with samarium(II) iodide.Sony VAIO VPCS11X9E/B Battery

In its usual oxidized form, samarium is added to ceramics and glasses where it increases absorption of infrared light. As a (minor) part of mischmetal, samarium is found in "flint" ignition device of many lighters and torches.

Radioactive samarium-153 is a beta emitter with a half-life of 46.3 hours.Sony VAIO VPCS123FGB Battery

It is used to kill cancer cells in the treatment oflung cancer, prostate cancer, breast cancer and osteosarcoma. For this purpose, samarium-153 is chelated with ethylene diamine tetramethylene phosphonate (EDTMP) and injected intravenously. The chelation prevents accumulation of radioactive samarium in the body that would result in excessive irradiation and generation of new cancer cells.Sony VAIO VPCS125EC Battery

The corresponding drug has several names including samarium (153Sm) lexidronam and its trade name is Quadramet.

Samarium-149 has high cross-section for neutron capture (41,000 barns) and is therefore used in the control rods of nuclear reactors.Sony VAIO VPCS128EC Battery

Its advantage compared to competing materials, such as boron and cadmium, is stability of absorption – most of the fusion and decay products of samarium-149 are other isotopes of samarium which are also good neutron absorbers. For example, the cross sections of samarium-151 is 15,000 barns, Sony VAIO VPCS129GC Battery

it is on the order of hundred barns for samarium-150, 152, 153, and is 6,800 barns for natural (mixed-isotope) samarium. Among the decay products in a nuclear reactor, samarium-149 is regarded as the second most important for the reactor design and operation after xenon-135.Sony VAIO VPCS12C7E/B Battery

Non-commercial and potential applications

Samarium-doped calcium fluoride crystals were used as an active medium in one of the first solid-state lasers designed and constructed by Peter Sorokin (co-inventor of the dye laser) and Mirek Stevenson at IBM research labs in early 1961.Sony VAIO VPCS12L9E/B Battery

This samarium laser emitted pulses of red light at 708.5 nm. It had to be cooled by liquid helium and thus did not find practical applications.

Another samarium-based laser became the first saturated X-ray laser operating at wavelengths shorter than 10 nanometers.Sony VAIO VPCS12V9E/B Battery

It provided 50-picosecond pulses at 7.3 and 6.8 nm suitable for applications in holography, high-resolution microscopy of biological specimens, deflectometry, interferometry and radiography of dense plasmas related to confinement fusion and astrophysics.Sony VAIO VPCW111XX/P Battery

Saturated operation meant that the maximum possible power was extracted from the lasing medium, resulting in the high peak energy of 0.3 mJ. The active medium was samarium plasma produced by irradiating samarium-coated glass with a pulsed infrared Nd-glass laser (wavelength ~1.05 µm).Sony VAIO VPCW111XX/PC Battery

The change in electrical resistivity in samarium monochalcogenides can be used in a pressure sensor or in a memory device triggered between a low-resistance and high-resistance state by external pressure,  and such devices are being developed commercially.Sony VAIO VPCW111XX/T Battery

Samarium monosulfide also generates electric voltage upon moderate heating to about 150 °C that can be applied in thermoelectric power converters.

The analysis of relative concentrations of samarium and neodymium isotopes 147Sm, 144Nd and 143Nd allows the determination of the age and origin of rocks and meteorites in samarium-neodymium dating.Sony VAIO VPCW111XX/W Battery

Both elements are lanthanides and have very similar physical and chemical properties. Therefore, Sm-Nd dating is either insensitive to partitioning of the marker elements during various geological processes, or such partitioning can well be understood and modeled from the ionic radiiof the involved elements.Sony VAIO VPCW111XXP Battery

Health issues

Samarium metal has no biological role in human body. Its salts stimulate metabolism, but it is unclear whether this is the effect of samarium or other lanthanides present with it. The total amount of samarium in adults is about 50 micrograms, mostly in liver and kidneys and with about 8 micrograms per liter being dissolved in the blood.Sony VAIO VPCW111XXT Battery

Samarium is not absorbed by plants to a measurable concentration and therefore is normally not a part of human diet. However, a few plants and vegetables may contain up to 1 part per million of samarium. Insoluble salts of samarium are non-toxic and the soluble ones are only slightly toxic.Sony VAIO VPCW111XXW Battery

When ingested, only about 0.05% of samarium salts is absorbed into the bloodstream and the remainder is excreted. From the blood, about 45% goes to the liver and 45% is deposited on the surface of the bones where it remains for about 10 years; the balance 10% is excreted.Sony VAIO VPCW115XG Battery,Sony VAIO VPCW115XGP Battery,Sony VAIO VPCW115XW/P Battery,Sony VAIO VPCW115XW/T Battery,Sony VAIO VPCW115XW/W Battery,Sony VAIO VPCW117XC/P Battery

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