Home 93 Np Neptunium back to the periodic table
 
Atomic number   93
Symbol   Np
Atomic weight   237.0482
Density [g/cm3]   20.48
Melting point [°C]   640
Boiling point [°C]   3900
1st Ionization energy [eV]   ---
Electronic configuration   [Rn] 5f4 6d 7s2
Oxidation number (most stable)   6, 5, 4, 3
Atomic radius [pm]   131 (a)
Ionic radius [pm]   95 (4+)
Abundance in crustal rocks [ppm]   0
Origin of the name   named after the planet Neptun, which follows Uranus in the order of the planets
Discovery   1940 by the American McMillan
Uses   no technical significance.
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 © 2004 Büro für angewandte Mineralogie · Dr. Stephan Rudolph · D-47918 Tönisvorst
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