Definition of neptunium in English:

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Pronunciation: /nɛpˈtjuːnɪəm/


[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: Np)
Example sentences
  • Each tank round is 10 pounds of solid uranium - 238 contaminated with plutonium, neptunium, americium.
  • In Basra they have found the bombs that were used had enriched uranium in them - neptunium.
  • Just as Neptune comes right after Uranus in the solar system, so, too, does neptunium come right after uranium in the periodic table.


Late 19th century: from Neptune, on the pattern of uranium (Neptune being the next planet beyond Uranus).

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Line breaks: nep¦tun|ium

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