Lanthanum definitions

lăn'thə-nəm
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 3,464°C; specific gravity 6.145 (at 25°C); valence 2, 3.
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A soft, malleable, silvery chemical element, one of the rare-earth elements and the first member of the lanthanide series: symbol, La; at. no. 57
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A soft, malleable, silvery-white metallic element of the lanthanide series. It is used to make glass for lenses and lights for movie and television studios. 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.
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A metallic chemical element (symbol La) with an atomic number of 57.
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Origin of lanthanum

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

Sentence Examples

  • Soc., 1901, 17, p. 63) by ignition of lanthanum sulphate at 500° C., the value obtained being 139 (O =16).

  • of yttria, Y203, and 42.75 of the oxides of erbium, cerium, didymium, lanthanum, iron, beryllium, calcium, magnesium and sodium.

  • In 1841 Mosander, having in 1839 discovered a new element lanthanum in the mineral cerite, isolated this element and also a hitherto unrecognized substance, didymia, from crude yttria, and two years later he announced the determination of two fresh constituents of the same earth, naming them erbia and terbia.

  • LANTHANUM [[[symbol]] La, atomic weight 139.0 (0=16)] one of the metals of the cerium group of rare earths.

  • For details of the complex process for the separation of the lanthanum salts from cerite, see R.

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Words near lanthanum in the Dictionary