Promethium鉕學術名詞鉕：化學元素、金屬材料、機械工程鏂：電機工程【金+叵】【元素76之舊名】：核能鉅：無機化合物英文釋義a soft silvery metallic element of the rare earth group having no stable isotope; was discovered in radioactive form as a fission product of uranium