Skip links

Neptunium (Np): Fun Facts and Information About the Element


What is the symbol? Np
What is the atomic number? 93
What is the atomic weight? 237
What is the melting point in Celsius? 640
What is the boiling point in Celsius? 3902
What is the density (g/cm3)? 20.2
What year was it discovered? 1940
Who discovered the element? “Edwin M. McMillian
Philip H. Abelson”
What group is the element in? 102
What is the electron configuration? [Rn] 5f4 6d1 7s2
What is the ionization energy? 6.2657
What element category is it in? Actinoids

Where is Neptunium Found?

The isotope 237Np is currently obtained in gram quantities as a by-product from nuclear reactors in the production of plutonium. Seventeen isotopes of neptunium are now recognized. The Oak Ridge National Laboratory has 237Np available for sale to its licensees and for export.

What is Neptunium Used For?

This isotope can be used as a component in neutron detection instruments.