| 释义 |
WordReference Random House Unabridged Dictionary of American English © 2024am•er•i•ci•um (am′ə rish′ē əm),USA pronunciation n. [Chem.]- Chemistrya transuranic element, one of the products of high-energy helium bombardment of uranium and plutonium. Symbol: Am;
at. no.: 95.
- Americ(a) + -ium 1945–50, American.
Collins Concise English Dictionary © HarperCollins Publishers:: americium /ˌæməˈrɪsɪəm/ n - a white metallic transuranic element artificially produced from plutonium. It is used as an alpha-particle source. Symbol: Am; atomic no: 95; half-life of most stable isotope, 243Am: 7.4 × 10³ years; valency: 2,3,4,5, or 6; relative density: 13.67; melting pt: 1176°C; boiling pt: 2607°C (est)
Etymology: 20th Century: from America (because it was discovered at Berkeley, California) + -ium |