from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A soft, silvery-white, malleable, ductile, metallic rare-earth element, obtained chiefly from monazite and bastnaesite and used in glass manufacture and with other rare earths in carbon lights for movie and television studio lighting. Atomic number 57; atomic weight 138.91; melting point 920°C; boiling point 3,469°C; specific gravity 5.98 to 6.186; valence 3. See Table at element.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A metallic chemical element (symbol La) with an atomic number of 57.

from the GNU version of the Collaborative International Dictionary of English

  • n. A rare element of the rare earth group of the metals, of atomic number 57, allied to aluminum. It occurs in certain rare minerals, as cerite, gadolinite, orthite, etc., and was so named from the difficulty of separating it from cerium, didymium, and other rare earth elements with which it is usually associated. Atomic weight 138.9. Symbol La.

from The Century Dictionary and Cyclopedia

  • n. Chemical symbol, La; atomic weight, 138. A rare metal discovered by Mosander in 1839–41, associated with didymium in the oxid of cerium, and so named from its properties having been previously concealed by those of cerium.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a white soft metallic element that tarnishes readily; occurs in rare earth minerals and is usually classified as a rare earth


from The American Heritage® Dictionary of the English Language, 4th Edition

New Latin, from Greek lanthanein, to escape notice (from the finding of the element hidden in oxide of cerium).

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Ancient Greek λανθάνω ("escape notice"), because it had gone long undetected in mineral ores.


  • Using material mined in past years, Molycorp produces rare-earth elements such as lanthanum, which is used in oil refining, and cerium, used in glass polishing and automotive catalytic converters.

    Molycorp, Hitachi Metals Reach Rare-Earth Deal

  • A metal oxide complex called lanthanum strontium manganite is ferromagnetic in large quantities. - latest science and technology news stories

  • The cost of quotas has become exorbitant for users of lanthanum, which is vital for the catalytic converters that clean the tailpipe pollution of conventional, gasoline-powered cars.

    NYT > Home Page

  • It produces rare-earth elements such as lanthanum and didymium.

    Envestnet, Chesapeake Midstream IPOs Up; Molycorp's Down

  • It cites China's increasing consumption and warns of a supply crunch for the metals, which include materials such as lanthanum, cerium and neodymium.


  • PW: From looking at the highest volume products such as lanthanum oxide, cerium oxide, cerium carbonate, dysprosium oxide, neodymium oxide etc.,

    Resource Investor - Main Content Feed

  • Separators will use their quotas to ship the more valuable material first, before using quotas on lower-priced elements such as lanthanum and cerium.

    Resource Investor - Main Content Feed

  • The group of 17 metallic elements, such as lanthanum, cerium, neodymium and europium, are used in petroleum refining, fiber-optic transmission, and military radar and missile-guidance systems. -- Top News

  • months, Molycorp and Lynas's deposits are skewed to "light rare earths" such as cerium and lanthanum, meaning major holes in the supply chain will still remain.

    The Globe and Mail - Home RSS feed

  • Toyota Motor Corp.'s Prius and other hybrid vehicles have lanthanum in their batteries.

    Highfliers Find Lower Orbit


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  • La.

    December 16, 2007