ALL meanings of neptunium
nep·tu·ni·um
N n - noun neptunium a transuranic element produced in nuclear reactors by the neutron bombardment of U-238: decays rapidly to plutonium and then to U-235. Symbol: Np; atomic number: 93. 1
- noun neptunium 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. 1
- noun neptunium a silvery metallic transuranic element synthesized in the production of plutonium and occurring in trace amounts in uranium ores. Symbol: Np; atomic no: 93; half-life of most stable isotope, 237Np: 2.14 × 106 years; valency: 3, 4, 5, or 6; relative density: 20.25; melting pt: 639±1°C; boiling pt: 3902°C (est) 0
- noun neptunium a silver-colored, radioactive, metallic chemical element, one of the actinides, produced by bombarding uranium atoms with neutrons: symbol, Np; at. no., 93 0