| 单词 | 辐射性 |
| 释义 | 〔thorianite〕A highly radioactive blackish, greenish, or yellow mineral, ThO2, isomorphous with uraninite. 方钍矿，方钍石：与沥青铀矿同晶形的黑色、绿色或黄色高辐射性矿石，ThO2 〔polonium〕A naturally radioactive metallic element, occurring in minute quantities as a product of radium disintegration and produced by bombarding bismuth or lead with neutrons. It has 27 isotopes ranging in mass number from 192 to 218, of which Po 210, with a half-life of 138.39 days, is the most readily available. Atomic number 84; melting point 254°C; boiling point 962°C; specific gravity 9.32; valence 2, 4. See table at element 钋：一种具有天然辐射性的金属元素，作为镭分裂的产物以极小量出现，可通过用中子轰击铋或铅获得。它从192到218的质量数中可排列为27种同位素，其中的钋210半衰期达138.39天，是最易得到的同位素。原子序数84；熔点254°C；沸点962°C；比重9.32；化合价2, 4 参见 element |
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