| Np | Neptunium | Atomic number : 93 Relative atomic mass (12C = 12.0000) : 237.0482 |
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| 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. |
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| G E O L O G I C A L D A T A | |
| Abundances 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 nil |
Daily dietary intake : nil Total mass of element in average (70 kg) person : nil |
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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. |