Neptunium

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Neptunium (symbol: Np) is a chemical element, a member of the actinoid series. All isotopes of neptunium are unstable, with half-lives of less than about two million years:[1] any neptunium that was present at the formation of the Solar System has long since decayed, although trace amounts of neptunium are naturally formed by the capture of neutrons by uranium-238.[2] Apart from these traces, neptunium is prepared artificially in nuclear reactors.

Neptunium was first prepared in 1939 by Edwin McMillan at the University of California Radiation Laboratory, by the neutron bombardment of uranium-238. It was named after the planet Neptune, by analogy with uranium, named after the planet Uranus.

Notes and references

Notes

References

  1. Audi, G.; Bersillon, O.; Blachot, J.; Wapstra, A. H. The NUBASE evaluation of nuclear and decay properties. Nucl. Phys. A 2003, 729, 3–128. doi:10.1016/j.nuclphysa.2003.11.001, <http://amdc.in2p3.fr/nubase/Nubase2003.pdf>.
  2. Peppard, D. F.; Mason, G. W.; Gray, P. R.; Mech, J. F. Occurrence of the (4n + 1) Series in Nature. J. Am. Chem. Soc. 1952, 74, 6081–84. DOI: 10.1021/ja01143a074.

External links

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