Np Neptunium     Atomic number : 93 
    Relative atomic mass (12C = 12.0000) :  237.0482 
    P H Y S I C A L     D A T A
Group 3 actinide
Density / kg m-3 :  20 250 [293 K]
Melting point / K :  913 
Boiling point / K :  4175
    D I S C O V E R Y
Neptunium was prepared in 1940 by Edwin M. McMillan and Philip H. Abelson at Berkeley, California, USA.
    G E O L O G I C A L     D A T A
Sun (relative to H = 1 × 1012) : n.a.
Earth's crust / p.p.m. : Neptunium is present in minute quantities in uranium ores, and is formed when one of the emitted neutrons, from a uranium atom undergoing fission, is captured by another uranium nucleus.
Seawater / p.p.m. : nil
    B I O L O G I C A L     D A T A
Level in humans
Daily dietary intake : nil
Total mass of element
in average (70 kg) person :


NetElements II  

A portrait of neptunium is available on the Visual Elements site. Up to 200 individual items of information on this element are available in The Elements.

Text copyright John Emsley 1999.   HTML and page layout copyright Simon Hall 1999.
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NetElements II last modified October 27th, 1999