radioactive element discovered in 1899, from Greek actin-, comb. form of aktis (genitive aktinos) "ray, radiance" (see actino-) + chemical suffix -ium.
实用例句
1. Any of a series of chemically similar, radioactive elements with atomic numbers ranging from 89 ( actinium ) through 103 ( lawrencium ).
锕类任何化学性质相似, 原子序数在89 ( 锕 ) 与103 ( 铹 ) 之间变化的放射性元素.
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2. The extraction mechanism and separation process of lanthanum and actinium were studied in HDEHP ( kerosene ) NO 3 system.
