pra⋅se⋅o⋅dym⋅i⋅um
[prey-zee-oh-dim-ee-uh
m, prey-see-] 
| a rare-earth, metallic, trivalent element, named from its green salts. Symbol: Pr; atomic weight: 140.91; atomic number: 59; specific gravity: 6.77 at 20°C. |
1880–85; < NL, equiv. to praseo- (comb. form repr. Gk prásios leek-green; see prase ) + (di)dymium
Based on the Random House Dictionary, © Random House, Inc. 2009.
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| pra·se·o·dym·i·um (prā'zē-ō-dĭm'ē-əm, prā'sē-) n. Symbol Pr A soft, silvery, malleable, ductile rare-earth element that develops a characteristic green tarnish in air. It occurs naturally with other rare earths in monazite and is used to color glass and ceramics yellow, as a core material for carbon arcs, and in metallic alloys. Atomic number 59; atomic weight 140.908; melting point 935°C; boiling point 3,127°C; specific gravity 6.8; valence 3, 4. See Table at element. [New Latin, from German Praseodym : Greek praseos, variant of prasios, leek-green (from prason, leek) + (di)dymium.] |
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Praseodymium
Pra`se*o*dym"i*um\, n. [Praseo- + didymium.] (Chem.) An elementary substance, one of the constituents of didymium; -- so called from the green color of its salts. Symbol Ps. Atomic weight 143.6.Cite This Source
praseodymium
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Main Entry: pra·seo·dym·i·um
Pronunciation: "prA-zE-O-'dim-E-&m, "prA-sE-
Function: noun
: a yellowish white trivalentmetallic element of the rare-earth group —symbol Pr; —see ELEMENT table
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praseodymium pra·se·o·dym·i·um (prā'zē-ō-dĭm'ē-əm, prā'sē-)
n.
Symbol Pr
A soft malleable ductile rare-earth element that develops a characteristic green tarnish in air and is used to color glass and ceramics yellow and in metallic alloy. Atomic number 59; atomic weight 140.908; melting point 931°C; boiling point 3,510°C; specific gravity 6.8; valence 3.
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| praseodymium (prā'zē-ō-dĭm'ē-əm) Pronunciation Key
Symbol Pr A soft, malleable, silvery metallic element of the lanthanide series that develops a green tarnish in air. It is used to add a yellow tint to glass and ceramics and to make the glass used in welding goggles. Atomic number 59; atomic weight 140.908; melting point 935°C; boiling point 3,127°C; specific gravity 6.8; valence 3, 4. See Periodic Table. |
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praseodymium
(Pr), chemical element, rare-earth metal of transition Group IIIb of the periodic table, used as the element in special alloys and, as its oxide, in glasses. Moderately soft, ductile, and malleable, this silvery metal rapidly displaces hydrogen from water and slowly reacts in air, developing a green oxide coating, which chips. For preservation, the metal must be sealed in a plastic covering or kept in mineral oil. Praseodymium was discovered in didymia, a mixture of several rare-earth oxides. From it, by repeated fractional crystallization of ammonium didymium nitrate, Carl Auer von Welsbach separated (1885) salts of the elements praseodymium (the green fraction) and neodymium. Praseodymium occurs in minerals such as monazite and bastnaesite and as one of the products of nuclear fission. Natural praseodymium is all stable isotope praseodymium-141. This element is commercially separated and purified by ion-exchange techniques; the reduction of the fluoride or chloride with calcium is one way in which the metal itself is prepared
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High Purity Praseodymium Oxide Metal, Carbonate, Nitrate, Pr6O11
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