| 释义 |
WordReference Random House Unabridged Dictionary of American English © 2024pra•se•o•dym•i•um (prā′zē ō dim′ē əm, prā′sē-),USA pronunciation n. [Chem.]- Chemistrya rare-earth, metallic, trivalent element, named from its green salts. Symbol: Pr;
at. wt.: 140.91;
at. no.: 59;
sp. gr.: 6.77 at 20°C.
- Neo-Latin, equivalent. to praseo- (combining form representing Greek prásios leek-green; see prase) + (di)dymium
- 1880–85
Collins Concise English Dictionary © HarperCollins Publishers:: praseodymium /ˌpreɪzɪəʊˈdɪmɪəm/ n - a malleable ductile silvery-white element of the lanthanide series of metals. It occurs principally in monazite and bastnaesite and is used with other rare earths in carbon-arc lights and as a pigment in glass. Symbol: Pr; atomic no: 59; atomic wt: 140.90765; valency: 3; relative density: 6.773; melting pt: 931°C; boiling pt: 3520°C
Etymology: 20th Century: New Latin, from Greek prasios of a leek-green colour + didymium |