出典:Wiktionary
出典:『Wiktionary』 (2026/04/24 23:44 UTC 版)
| Chemical element |
|---|
| Np Atomic number 93 neptunium |
| Previous: ← uranium (U) |
| Next: plutonium (Pu) → |
| English Wikipedia article on Neptunium |
From Neptune + -ium, after the planet. The previous element is uranium, named after the previous planet: Uranus.
| Chemical element |
|---|
| Np Atomic number 93 neptunium |
| Previous: ← uranium (U) |
| Next: plutonium (Pu) → |
出典:Wikipedia
出典:『Wikipedia』 (2011/07/27 17:30 UTC 版)
Neptunium (
/nɛpˈtjuːniəm/ nep-tew-nee-əm) is a chemical element with the symbol Np and atomic number 93. A radioactive metal, neptunium is the first transuranic element and belongs to the actinide series. Its most stable isotope, 237Np, is a by-product of nuclear reactors and plutonium production and it can be used as a component in neutron detection equipment. Neptunium is also found in trace amounts in uranium ores due to transmutation reactions.