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出典:『Wikipedia』 (2011/08/06 18:13 UTC 版)

英語による解説

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Selenium (Se) has six naturally occurring isotopes, five of which are stable: ⁷⁴Se, ⁷⁶Se, ⁷⁷Se, ⁷⁸Se, and ⁸⁰Se. The last three also occur as fission products, along with 79Se which has a halflife of 327,000 years, and ⁸²Se which has a very long half-life (~10²⁰ yr, decaying via double beta decay to 82Kr) and for practical purposes can be considered to be stable. 23 other unstable isotopes have been characterized, the longest-lived being ⁷⁹Se with a half-life 327,000 years, ⁷⁵Se with a half-life of 120 days, and ⁷²Se with a half-life of 8.40 days. All other isotopes have half-lives less than a day, most less than a minute.