free radical

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++ˌfree ˈradical noun [countable] technical  an atom or group of atoms with at least one free electron, which combines with other atoms very easily 自由基，游离基 It is thought that free radicals can damage cells. 自由基被认为会破坏细胞。

Examples from the Corpus

free radical• As a result, new classes of free radical are particularly interesting to chemists.

ˌfree ˈradical nounChineseSyllable  

an atoms with or one of Corpus at least group atom

free radical
ˌfree ˈradical noun [countable] technical
an atom or group of atoms with at least one free electron, which combines with other atoms very easily:
    It is thought that free radicals can damage cells.

free radicalBrE /ˌfriː ˈrædɪkl/ 🔊NAmE /ˌfriː ˈrædɪkl/ 🔊 noun (chemistry 化学) an atom or group of atoms that has an electron that is not part of a pair, causing it to take part easily in chemical reactions. Free radicals in the body are thought to be one of the causes of diseases such as cancer. 自由基；游离基  ➡  see also antioxidant (1)