n. 镧

[化] 镧La

[医] 镧(57号元素)

[ noun ]
a white soft metallic element that tarnishes readily; occurs in rare earth minerals and is usually classified as a rare earth
<noun.substance>

Lanthanum \Lan"tha*num\ (l[a^]n"th[.a]*n[u^]m), n. [NL., fr. Gr.
lanqa`nein to lie hid, to be concealed.] (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. [Formerly
written also {lanthanium}.]