| 单词 | radon |
| 释义 | Word Frequency radon(ˈreɪdɒn) noun a colourless radioactive element of the rare gas group, the most stable isotope of which, radon-222, is a decay product of radium. It is used as an alpha particle source in radiotherapy. Symbol: Rn; atomic no: 86; half-life of222Rn: 3.82 days; valency: 0; density: 9.73 kg/m3; melting pt: –71°C; boiling pt: –61.7°C Word origin C20: from radium + -on |
| 随便看 |
英语词典包含233703条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。