American Heritage® Dictionary of the English Language, Fourth 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.
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. Its specific gravity is about 6.13. It is malleable, not ductile, tarnishes quickly in air, and is soluble in hydrochloric and sulphuric acids with evolution of hydrogen.
GNU Webster's 1913
- n. (Chem.) 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.
- n. a white soft metallic element that tarnishes readily; occurs in rare earth minerals and is usually classified as a rare earth
- From Ancient Greek λανθάνω ("escape notice"), because it had gone long undetected in mineral ores. (Wiktionary)
- New Latin, from Greek lanthanein, to escape notice (from the finding of the element hidden in oxide of cerium). (American Heritage® Dictionary of the English Language, Fourth Edition)
“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.”
“A metal oxide complex called lanthanum strontium manganite is ferromagnetic in large quantities.”
“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.”
“It produces rare-earth elements such as lanthanum and didymium.”
“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.,”
“Separators will use their quotas to ship the more valuable material first, before using quotas on lower-priced elements such as lanthanum and cerium.”
“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.”
“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.”
“Toyota Motor Corp.'s Prius and other hybrid vehicles have lanthanum in their batteries.”
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