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PRASEODYMIUM Basic information
PRASEODYMIUM Chemical Properties
  • Melting point:931 °C(lit.)
  • Boiling point:3520 °C(lit.)
  • Density 6.71 g/mL at 25 °C(lit.)
  • storage temp. Flammables area
  • form powder
  • color White
  • Specific Gravity6.782
  • Resistivity68 μΩ-cm, 20°C
  • Water Solubility Reacts with water.
  • Sensitive Air & Moisture Sensitive
  • Merck 13,7797
  • CAS DataBase Reference7440-10-0(CAS DataBase Reference)
  • EPA Substance Registry SystemPraseodymium (7440-10-0)
Safety Information
PRASEODYMIUM Usage And Synthesis
  • UsesPraseodymium resembles the typical trivalent rare earths, however, it will exhibit a +4 state when stabilized in a zirconia host. The element is found in most all light rare earth derivatives.
    It is highly valued for ceramics as a bright yellow pigment in praseodymium doped zirconia because of its optimum reflectance at 560 nm.
    Much research is being done on its optical properties for use in amplification of telecommunication systems, including as a doping agent in Fluoride fibers.
    Praseodymium is present in the rare earth mixture whose Fluoride forms the core of carbon arc lights which are used in the motion picture industry for studio lighting and projector lights.
    Doping Praseodymium in Fluoride glass allows it to be used as a single mode fiber optical amplifier.
    It is also used in the scintillator for medical CAT scans.
    As an alloying agent with Magnesium to create high-strength metals that are used in aircraft engines.
    Praseodymium compounds give glasses and enamels a yellow color.
    Praseodymium Metal, is used as high-strength alloying agent in the Magnesium used in parts of aircraft engines. It is an important alloying agent in Neodymium-Iron-Boron magnets. Praseodymium is used to create high-power magnets notable for their strength and durability. It also used in lighters, torch strikers, 'flint and steel' fire starters, etc.
  • Chemical Propertiesgrey powder
  • Physical propertiesPraseodymium is a silvery-white, soft metal that is easily formed into various shapes. Whenthe pure metal is exposed to the air, a green oxide coating forms on its surface. To preventoxidation, praseodymium is usually kept in oil in a covered container.
    Its melting point is 931°C, its boiling point is 3,520°C, and its density is 6.77g/cm3.
  • IsotopesThere are 45 isotopes of praseodymium. All are artificially produced and radioactivewith half-lives ranging from several hundred nanoseconds to 23.6 days. Only oneis stable (Pa-141), and it makes up 100% of the praseodymium found in the Earth’scrust.
  • Origin of NameThe name is derived from two Greek words, prasios and didymos, which together mean “green twins.”
  • OccurrencePraseodymium is the 41st most abundant element on Earth and is found in the ores of monazite,cerite, bastnasite, and allanite along with other rare-earths. Praseodymium is also the stableisotope resulting from the process of fission of some other heavy elements, such as uranium.
    Praseodymium is mainly found in monazite sands and bastnasite ores. The monazite sandscontain all of the rare-earths and are found in river sand in India and Brazil as well as inFlorida beach sand. A large deposit of bastnasite exists in California.
    Praseodymium is separated from its ore and other rare-earths by a process called ionexchange, which exchanges one type of ion for another.
  • CharacteristicsAs a metal, Pr is hygroscopic (adsorbs water) and tarnishes in the atmosphere. It will reactwith water to liberate hydrogen. It is soluble in acids and forms greenish salts, along with someother rare-earths. It is used to fabricate the electrodes for high-intensity lights.
  • HistoryIn 1879, Lecoq de Boisbaudran isolated a new earth, samaria, from didymia obtained from the mineral samarskite. Six years later, in 1885, von Welsbach separated didymia into two others, praseodymia and neodymia, which gave salts of different colors. As with other rare earths, compounds of these elements in solution have distinctive sharp spectral absorption bands or lines, some of which are only a few Angstroms wide. Praseodymium occurs along with other rare-earth elements in a variety of minerals. Monazite and bastnasite are the two principal commercial sources of the rare-earth metals. Ion-exchange and solvent extraction techniques have led to much easier isolation of the rare earths and the cost has dropped greatly. Thirty-seven isotopes and isomers are now recognized. Praseodymium can be prepared by several methods, such as by calcium reduction of the anhydrous chloride or fluoride. Misch metal, used in making cigarette lighters, contains about 5% praseodymium metal. Praseodymium is soft, silvery, malleable, and ductile. It was prepared in relatively pure form in 1931. It is somewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that splits off when exposed to air. As with other rare-earth metals it should be kept under a light mineral oil or sealed in plastic. The rare-earth oxides, including Pr2O3, are among the most refractory substances known. Along with other rare earths, it is widely used as a core material for carbon arcs used by the motion picture industry for studio lighting and projection. Salts of praseodymium are used to color glasses and enamels; when mixed with certain other materials, praseodymium produces an intense and unusually clean yellow color in glass. Didymium glass, of which praseodymium is a component, is a colorant for welder’s goggles. The metal (99.9% pure) is priced at about $4/g.
  • UsesPraseodymium salts, ingredient of mischmetal, core material for carbon arcs, colorant in glazes and glasses, catalyst, phosphors, lasers.
  • UsesPraseodymium’s major use is as an alloying agent along with magnesium to produce highstrengthsteel that is used in airplane engines and automobiles parts. Notwithstanding its greenish color, another important use of praseodymium is as a yellow pigment to color glassand ceramics. Along with several other rare-earths, it is also used to form the electrodes forhigh-intensity arc lamps.
    It is used to manufacture safety goggles that filter out strong yellow light (used in welding,for example). Misch metal uses about 5% Pr in the manufacture of cigarette lighter flints.
  • DefinitionPr. Metallic element of atomic number 59, group IIIB of the periodic table, one of the rare earth elements of the lanthanide group, aw 140.9077, valences = 3, 4. No stable isotopes.
  • DefinitionA soft ductile malleable silvery element of the lanthanoid series of metals. It occurs in association with other lanthanoids. Praseodymium is used in several alloys, as a catalyst, and in enamel and yellow glass for eye protection. Symbol: Pr; m.p. 931°C; b.p. 3512°C; r.d. 6.773 (20°C); p.n. 59; r.a.m. 140.91.
  • Definitionpraseodymium: Symbol Pr. A softsilvery metallic element belonging tothe lanthanoids; a.n. 59; r.a.m.140.91; r.d. 6.773; m.p. 931°C; b.p.3512°C. It occurs in bastnasite andmonazite, from which it is recoveredby an ion-exchange process. The onlynaturally occurring isotope ispraseodymium–141, which is notradioactive; however, fourteen radioisotopeshave been produced. It isused in mischmetal, a rare-earthalloy containing 5% praseodymium,for use in lighter ?ints. Another rareearthmixture containing 30%praseodymium is used as a catalyst in cracking crude oil. The element wasdiscovered by C. A. von Welsbach in1885.
  • PreparationPraesodymium may be recovered from its minerals monazite and bastanasite. The didymia extract of rare earth minerals is a mixture of praesodymia and neodymia, primarily oxides of praesodymium and neodymium. Several methods are known for isolation of rare earths. These are applicable to all rare earths including praesodymium. They include solvent extractions,ionexchange, and fractional crystallization. While the first two methods form easy and rapid separation of rare earth metals, fractional crystallization is more tedious. Extractions and separations of rare earths have been discussed in detail earlier (see Neodymium and Cerium).
    Praesodymium metal can be obtained from its anhydrous halides by reduction with calcium. The metal also may be prepared by electrolysis of fused praesodymium chloride at elevated temperatures (about 1,000°C).Alternatively, an eutectic mixture of praesodymium chloride, potassium chloride, and sodium chloride may be electrolyzed. In such electrolysis graphite is the anode and tungsten the cathode.
  • HazardIf praseodymium gets wet or is submerged in water, the hydrogen released may explode. Itmust be kept dry and protected from the atmosphere.
PRASEODYMIUM Preparation Products And Raw materials
PRASEODYMIUM(7440-10-0)Related Product Information
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