actinium
工業(yè)科技

        A soft silvery -white radioac-tive metallic element that is the first mem-ber of the actinoid series. It occurs in mi-nute quantities in uranium ores and themetal can be obtained by reducing the trif-luoride with lithium. It can be produced byneutron bomb......（本文共 639 字）     [閱讀本文] >>