|an extraordinary or unusual thing, person, or event; an exceptional example or instance.|
|a chattering or flighty, light-headed person.|
|music a variant spelling of lah|
|—the internet domain name for|
|Lao People's Democratic Republic|
|—the chemical symbol for|
The symbol for the element lanthanum.
The symbol for lanthanum.
|lanthanum (lān'thə-nəm) Pronunciation Key
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. See Periodic Table.
(La), chemical element, rare-earth metal of transition Group IIIb of the periodic table, prototype of the lanthanoid series of elements. Lanthanum is a ductile and malleable, silvery-white metal, soft enough to be cut with a knife. The element was discovered as the oxide (lanthana) in 1839 by Carl Gustaf Mosander, who distinguished it from cerium oxide (ceria). Its name is derived from the Greek lanthanein, meaning "to be concealed," indicating that it is difficult to isolate
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