| 释义 |
WordReference Random House Learner's Dictionary of American English © 2024co•balt /ˈkoʊbɔlt/USA pronunciation n. [uncountable]- Chemistry, Nutritiona hard whitish metal element used to produce a blue coloring.
WordReference Random House Unabridged Dictionary of American English © 2024co•balt (kō′bôlt),USA pronunciation n. - Chemistry, Nutritiona silver-white metallic element with a faint pinkish tinge, occurring in compounds whose silicates afford important blue coloring substances for ceramics. Symbol: Co;
at. wt.: 58.933;
at. no.: 27;
sp. gr.: 8.9 at 20°C.
- German Kobalt, variant of Kobold kobold
- 1675–85
Collins Concise English Dictionary © HarperCollins Publishers:: cobalt /ˈkəʊbɔːlt/ n - a brittle hard silvery-white element that is a ferromagnetic metal: occurs principally in cobaltite and smaltite and is widely used in alloys. The radioisotope cobalt-60, with a half-life of 5.3 years, is used in radiotherapy and as a tracer. Symbol: Co; atomic no: 27; atomic wt: 58.93320; valency: 2 or 3; relative density: 8.9; melting pt: 1495°C; boiling pt: 2928°C
Etymology: 17th Century: German Kobalt, from Middle High German kobolt goblin; from the miners' belief that malicious goblins placed it in the silver ore |