neodymium(redirected from Tyrium)
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neodymium(nē'ōdĭm`ēəm), metallic chemical element; symbol Nd; at. no. 60; at. wt. 144.242; m.p. about 1,021°C;; b.p. about 3,068°C;; sp. gr. 7.004 at 20°C;; valence +3. Neodymium is a lustrous silver-yellow metal. It is one of the rare-earth metalsrare-earth metals,
in chemistry, group of metals including those of the lanthanide series and actinide series and usually yttrium, sometimes scandium and thorium, and rarely zirconium. Promethium, which is not found in nature, is not usually considered a rare-earth metal.
..... Click the link for more information. in the lanthanide serieslanthanide series,
a series of metallic elements, included in the rare-earth metals, in Group 3 of the periodic table. Members of the series are often called lanthanides, although lanthanum (atomic number 57) is not always considered a member of the series.
..... Click the link for more information. of Group 3 of the periodic tableperiodic table,
chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the table entitled
..... Click the link for more information. . It exists in two distinct forms (see allotropyallotropy
[Gr.,=other form]. A chemical element is said to exhibit allotropy when it occurs in two or more forms in the same physical state; the forms are called allotropes.
..... Click the link for more information. ); at room temperature it has a hexagonal crystalline structure, but when heated above about 800°C; it assumes a face-centered cubic conformation with specific gravity about 6.8. The metal tarnishes in air; the coating formed does not protect the metal from further oxidation, so it must be stored away from contact with air. The oxide (neodymia, Nd2O3) is light blue. The metal is also attacked by water and by acids. Its salts form various red aqueous solutions. Neodymium is present in the minerals monazitemonazite
, yellow to reddish-brown natural phosphate of the rare earths, mainly the cerium and lanthanum metals, usually with some thorium. Yttrium, calcium, iron, and silica are frequently present.
..... Click the link for more information. and bastnasite. The metal may be prepared from its halides by reduction. Neodymium is one of several metals in an alloy commonly used in cigarette lighter flints. It also is used in powerful permanent magnets and in coloring glasses. The earth didymia is a mixture of the oxides of neodymium and praseodymium. The lenses of goggles used by glassblowers are made with a didymium glass that absorbs the yellow sodium glare of the flame. Neodymium was discovered in 1885 by C. A. von Welsbach who separated Mosander's "didymium" into two components, the earths neodymia and praseodymia.
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A metallic element, symbol Nd, with atomic weight 144.24, atomic number 60; a member of the rare-earth group of elements.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
a toxic silvery-white metallic element of the lanthanide series, occurring principally in monazite: used in colouring glass. Symbol: Nd; atomic no.: 60; atomic wt.: 144.24; valency: 3; relative density: 6.80 and 7.00 (depending on allotrope); melting pt.: 1024?C; boiling pt.: 3127?C
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