Np
Neptunium
Z 93 237.0 g/molActinide Radioactive
Nucleus
93 Protons
144 Neutrons
93 Electrons (7 Valence)
Shell distribution: K2 • L8 • M18 • N32 • O22 • P9 • Q2
Electron Configuration
Energy
7p
6d
5f
7s
6p
5d
4f
6s
5p
4d
5s
4p
3d
4s
3p
3s
2p
2s
1s
[Rn]5f46d17s2
Oxidation States
CommonRare
0
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Radii
Empirical
175 pm1.75 Å
Calculated
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Covalent
190±1 pm1.9±0.01 Å
Van der Waals
221 pm2.21 Å
IonicNp5+
75 pm0.75 Å
Crystal Structure
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OrthorhombicStandard state
Pearson symbol
oP8
Space group
Pnma No. 62
Density
20.2 g/cm³