Atomic Radii
Atomic Radius
Bohr Radius
Covalent Radius
Van der Waals
| Neptunium | |
| Electron Configuration | 2,8,18,32,22,9,2 |
| Electron Configuration | [Rn] 5f4 6d1 7s2 |
| Electronegativity | 1.36 |
| Enthalpy of Fusion | 9.46 kJ mol-1 |
| Enthalpy of Vaporisation | 336.6 kJ mol-1 |
| Heat Capacity | 29.46 J mol-1 K-1 |
| Thermal Conductivity | 6.3 W m-1 K-1 |
| Thermal Expansion | ? μm m-1 K-1 |
| Magnetic ordering | No data |
| Electrical resistivity | 1.220 Ω m |
| Atomic Radii |
|
| Atomic Radius
|
175 pm |
| Bohr Radius
|
0 pm |
| Covalent Radius
|
0 pm |
| Van der Waals
|
0 pm |
| Oxidation States |
|
| Main
|
Np+5 |
| Other
|
Np+2, Np+3, Np+4, Np+6, Np+7 |
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
597 |