|Group||Actinides||Melting point||644°C, 1191°F, 917 K|
|Period||7||Boiling point||3902°C, 7056°F, 4175 K|
|Block||f||Density (g cm−3)||20.2|
|Atomic number||93||Relative atomic mass|||
|State at 20°C||Solid||Key isotopes||237Np|
|Electron configuration||[Rn] 5f46d17s2||CAS number||7439-99-8|
|ChemSpider ID||22375||ChemSpider is a free chemical structure database|
- Neptunium has an atomic number of 93, present in the actinide series of on the Periodic Table.
- Neptunium is found between uranium (92), the last of the natural elements, and plutonium (94).
- Like its two closest neighbors, it belongs to the actinide series, so named because of the chemical affinity with actinium (89).
- First, of the artificially produced elements, Np starts the series of the 11 transuranic elements, all radioactive, heavy metals.
- Like plutonium and uranium, neptunium (237) is an alpha emitter, which means that as it disintegrates, it emits a particle formed of two protons and two neutrons (similar to a helium nucleus). It then transmutes into protactinium 233 (element 91).
- Neptunium is produced through neutron bombardment of a uranium nucleus.
- Plutonium 238 is obtained as a result of using Np 237 as a target in research reactors, which constitutes a significant source of energy for space missions.
- Found in nuclear waste as a mixture with other fission products, Neptunium 237 also appears in increasing quantity as a product of americium 241.
- With a critical mass of 73 kg, Neptunium is considered usable in nuclear weapons. Although, no country is known to have used it to make a nuclear explosive device.
- Np with no major commercial uses of Np is needed for research and exploratory work.