Neptunium
Neptunium (镎, symbol Np) is chemical element number 93, an Actinide in period 7 of the periodic table, with a standard atomic weight of about 237. First synthetic transuranium element. Used in neutron detection equipment.
Properties
| Atomic number | 93 |
|---|---|
| Symbol | Np |
| Atomic mass | 237 u |
| Category | Actinide |
| Period | 7 |
| Group | — |
| Electron configuration | [Rn] 5f⁴ 6d¹ 7s² |
| Electronegativity | 1.36 |
| Covalent radius | 190 pm |
| Density | 20.45 g/cm³ |
| Melting point | 917 K |
| Boiling point | 4273 K |
| Discovery | McMillan & Abelson, 1940 |
Overview
First synthetic transuranium element. Used in neutron detection equipment. Element 93, Neptunium (Np), is an Actinide found in period 7. As an actinide it is typically radioactive and closely tied to nuclear technology.
It has the configuration [Rn] 5f⁴ 6d¹ 7s² and an electronegativity near 1.36; its 2 outer-shell electrons drive its bonding. Under standard conditions it exists as a solid; it melts near 917 K (643.9 °C), boils near 4273 K (3999.9 °C), has a density around 20.45 g/cm³.
It is widely used in Nuclear and Research. On the safety side, it carries a high hazard rating. It was first described by McMillan & Abelson in 1940. Use the comparison tool to line it up against other elements.
Electron shells
Electrons per shell: 2 · 8 · 18 · 32 · 22 · 9 · 2
Main uses
- Nuclear
- Research
Hazard
Compounds containing Neptunium
No compounds in this knowledge base contain Neptunium yet.
Data sources
Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.