Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is somewhat more resistant to corrosion 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. For this reason, praseodymium is usually stored under a light mineral oil or sealed in glass.
Contrary to other rare-earth metals, which show antiferromagnetic or/and ferromagnetic ordering at low temperatures, Pr is paramagnetic at any temperature above 1 K.
 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:
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]
Praseodymium dissolves readily in dilute sulfuric acid to form solutions containing green Pr(III) ions, which exist as a [Pr(OH2)9]3+ complexes:
2 Pr (s) + 3 H2SO4 (aq) → 2 Pr3+(aq) + 3 SO2−
4 (aq) + 3 H2 (g)
See also: Category:Praseodymium 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. 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. 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.
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
Main article: isotopes of praseodymium
Naturally occurring praseodymium is composed of one stable isotope, 141Pr. Thirty-eight radioisotopes have been characterized with the most stable being 143Pr with a half-life of 13.57 days and 142Pr with a half-life of 19.12 hours. All of the remaining radioactive isotopes have half-lives that are less than 5.985 hours and the majority of these have half-lives that are less than 33 seconds. This element also has six meta states with the most stable being 138mPr (t½ 2.12 hours), 142mPr (t½ 14.6 minutes) and 134mPr (t½ 11 minutes).
The isotopes of praseodymium range in atomic weight from 120.955 u (121Pr) to 158.955 u (159Pr). The primary decay mode before the stable isotope, 141Pr, is electron capture and the primary mode after is beta minus decay. The primary decay products before 141Pr are element 58 (cerium) isotopes and the primary products after are element 60 (neodymium) isotopes.
The name praseodymium comes from the Greek prasios (πράσιος), meaning green, and didymos (δίδυμος), twin. Praseodymium is frequently misspelled as praseodynium.
In 1841, Mosander extracted the rare earth didymium from lanthana. 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. In 1885, the Austrian chemist baron Carl Auer von Welsbach separated didymium into two elements, praseodymium and neodymium, which gave salts of different colors.
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". 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. 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.
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. 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, 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. 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. So LC is starting to replace LCP as a result.
Praseodymium is available in small quantities in Earth’s crust (9.5 ppm). It is found in the rare earth minerals monazite and bastnäsite, typically comprising about 5% of the lanthanides contained therein, and can be recovered from these minerals by an ion exchange process, or by counter-current solvent extraction. Misch metal, used in making cigarette lighters, contains about 5% praseodymium metal.
Uses of praseodymium:
- As an alloying agent with magnesium to create high-strength metals that are used in aircraft engines.
- Praseodymium forms the core of carbon arc lights which are used in the motion picture industry for studio lighting and projector lights.
- Praseodymium compounds give glasses and enamels a yellow color.
- Praseodymium is used to color cubic zirconia yellow-green, to simulate the mineral peridot.
- Praseodymium is a component of didymium glass, which is used to make certain types of welder's and glass blower's goggles.
- Silicate glass doped with praseodymium ions has been used to slow a light pulse down to a few hundred meters per second.
- 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.
- 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.
Like all rare earths, praseodymium is of low to moderate toxicity. Praseodymium has no known biological role.
歡迎來到Bewise Inc.的世界，首先恭喜您來到這接受新的資訊讓產業更有競爭力，我們是提供專業刀具製造商，應對客戶高品質的刀具需求，我們可以協助客戶滿足您對產業的不同要求，我們有能力達到非常卓越的客戶需求品質，這是現有相關技術無法比擬的，我們成功的滿足了各行各業的要求，包括：精密HSS DIN切削刀具、協助客戶設計刀具流程、DIN or JIS 鎢鋼切削刀具設計、NAS986 NAS965 NAS897 NAS937orNAS907 航太切削刀具,NAS航太刀具設計、超高硬度的切削刀具、醫療配件刀具設計、複合式再研磨機、PCD地板專用企口鑽石組合刀具、粉末造粒成型機、主機版專用頂級電桿、PCBN刀具、PCD刀具、單晶刀具、PCD V-Cut刀、捨棄式圓鋸片組、粉末成型機、航空機械鉸刀、主機版專用頂級電感、’汽車業刀具設計、電子產業鑽石刀具、木工產業鑽石刀具、銑刀與切斷複合再研磨機、銑刀與鑽頭複合再研磨機、銑刀與螺絲攻複合再研磨機等等。我們的產品涵蓋了從民生刀具到工業級的刀具設計；從微細刀具到大型刀具；從小型生產到大型量產；全自動整合；我們的技術可提供您連續生產的效能，我們整體的服務及卓越的技術，恭迎您親自體驗！！
BW Bewise Inc. Willy Chen email@example.com firstname.lastname@example.org www.tool-tool.com skype:willy_chen_bw mobile:0937-618-190 Head &Administration Office No.13,Shiang Shang 2nd St., West Chiu Taichung,Taiwan 40356 http://www.tool-tool.com/ / FAX:+886 4 2471 4839 N.Branch 5F,No.460,Fu Shin North Rd.,Taipei,Taiwan S.Branch No.24,Sec.1,Chia Pu East Rd.,Taipao City,Chiayi Hsien,Taiwan
Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, its our pleasure to serve for you. BW product including: cutting tool、aerospace tool .HSS DIN Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、NAS986 NAS965 NAS897 NAS937orNAS907 Cutting Tools,Carbide end mill、disc milling cutter,Aerospace cutting tool、hss drill’Фрезеры’Carbide drill、High speed steel、Compound Sharpener’Milling cutter、INDUCTORS FOR PCD’CVDD(Chemical Vapor Deposition Diamond )’PCBN (Polycrystalline Cubic Boron Nitride) ’Core drill、Tapered end mills、CVD Diamond Tools Inserts’PCD Edge-Beveling Cutter(Golden Finger’PCD V-Cutter’PCD Wood tools’PCD Cutting tools’PCD Circular Saw Blade’PVDD End Mills’diamond tool. INDUCTORS FOR PCD . POWDER FORMING MACHINE ‘Single Crystal Diamond ‘Metric end mills、Miniature end mills、Специальные режущие инструменты ‘Пустотелое сверло ‘Pilot reamer、Fraises’Fresas con mango’ PCD (Polycrystalline diamond) ‘Frese’POWDER FORMING MACHINE’Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、Staple Cutter’PCD diamond cutter specialized in grooving floors’V-Cut PCD Circular Diamond Tipped Saw Blade with Indexable Insert’ PCD Diamond Tool’ Saw Blade with Indexable Insert’NAS tool、DIN or JIS tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills’end mill grinder’drill grinder’sharpener、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angel carbide end mills、Carbide torus cutters、Carbide ball-nosed slot drills、Mould cutter、Tool manufacturer.
Bewise Inc. www.tool-tool.com
（２）Carbide Cutting tools設計
Bewise Inc. talaşlı imalat sanayinde en fazla kullanılan ve üç eksende (x,y,z) talaş kaldırabilen freze takımlarından olan Parmak Freze imalatçısıdır. Çok geniş ürün yelpazesine sahip olan firmanın başlıca ürünlerini Karbür Parmak Frezeler, Kalıpçı Frezeleri, Kaba Talaş Frezeleri, Konik Alın Frezeler, Köşe Radyüs Frezeler, İki Ağızlı Kısa ve Uzun Küresel Frezeler, İç Bükey Frezeler vb. şeklinde sıralayabiliriz.
BW специализируется в научных исследованиях и разработках, и снабжаем самым высокотехнологичным карбидовым материалом для поставки режущих / фрезеровочных инструментов для почвы, воздушного пространства и электронной индустрии. В нашу основную продукцию входит твердый карбид / быстрорежущая сталь, а также двигатели, микроэлектрические дрели, IC картонорезальные машины, фрезы для гравирования, режущие пилы, фрезеры-расширители, фрезеры-расширители с резцом, дрели, резаки форм для шлицевого вала / звездочки роликовой цепи, и специальные нано инструменты. Пожалуйста, посетите сайт www.tool-tool.com для получения большей информации.
BW is specialized in R&D and sourcing the most advanced carbide material with high-tech coating to supply cutting / milling tool for mould & die, aero space and electronic industry. Our main products include solid carbide / HSS end mills, micro electronic drill, IC card cutter, engraving cutter, shell end mills, cutting saw, reamer, thread reamer, leading drill, involute gear cutter for spur wheel, rack and worm milling cutter, thread milling cutter, form cutters for spline shaft/roller chain sprocket, and special tool, with nano grade. Please visit our web www.tool-tool.com for more info.