| 释义 |
WordReference Random House Learner's Dictionary of American English © 2024po•tas•si•um /pəˈtæsiəm/USA pronunciation n. [uncountable]- Chemistrya silvery white metallic element that burns rapidly in the air and whose compounds are used as fertilizer.
WordReference Random House Unabridged Dictionary of American English © 2024po•tas•si•um (pə tas′ē əm),USA pronunciation n. [Chem.]- Chemistrya silvery-white metallic element that oxidizes rapidly in the air and whose compounds are used as fertilizer and in special hard glasses. Symbol: K;
at. wt.: 39.102;
at. no.: 19;
sp. gr.: 0.86 at 20°C.
- Neo-Latin; see potassa, -ium
- 1800–10
Collins Concise English Dictionary © HarperCollins Publishers:: potassium /pəˈtæsɪəm/ n - a light silvery element of the alkali metal group that is highly reactive and rapidly oxidizes in air; occurs principally in carnallite and sylvite. It is used when alloyed with sodium as a cooling medium in nuclear reactors and its compounds are widely used, esp in fertilizers. Symbol: K; atomic no: 19; atomic wt: 39.0983; valency: 1; relative density: 0.862; melting pt: 63.71°C; boiling pt: 759°C
Etymology: 19th Century: New Latin potassa potashpoˈtassic adj |