neptunium
/nepˈtjuːnɪəm/noun
mass noun
- the chemical element of atomic number 93, a radioactive metal of the actinide series. Neptunium was discovered as a product of the bombardment of uranium with neutrons, and occurs only in trace amounts in nature. (Symbol:
N P)（化学元素）镎（符号：N P）。
词源
late 19th cent.: from N EPTUNE, on the pattern of uranium (Neptune being the next planet beyond Uranus).