| 释义 |
WordReference Random House Unabridged Dictionary of American English © 2024lan•tha•num (lan′thə nəm),USA pronunciation n. [Chem.]- Chemistrya rare-earth, trivalent, metallic element, allied to aluminum, found in certain minerals, as monazite. Symbol: La;
at. wt.: 138.91;
at. no.: 57;
sp. gr.: 6.15 at 20°C.
- Greek lanthánein to escape notice; referring to its position on the periodic table) + -um, variant of -ium -ium
- Neo-Latin (1841), equivalent. to lanthan- (
Collins Concise English Dictionary © HarperCollins Publishers:: lanthanum /ˈlænθənəm/ n - a silvery-white ductile metallic element of the lanthanide series, occurring principally in bastnaesite and monazite: used in pyrophoric alloys, electronic devices, and in glass manufacture. Symbol: La; atomic no: 57; atomic wt: 138.9055; valency: 3; relative density: 6.145; melting pt: 918°C; boiling pt: 3464°C
Etymology: 19th Century: New Latin, from Greek lanthanein to lie unseen |