93 Np 237
Neptunium
Actinide
Neptunium (Np) is a chemical element with atomic number 93, classified as a actinide. At room temperature it is a solid. It was discovered in 1940 by Edwin McMillan, Philip Abelson.
Properties
- Atomic number
- 93
- Atomic mass
- 237 u
- Category
- Actinide
- Group
- 0
- Period
- 7
- Block
- f-block
- Electron configuration
- [Rn] 5f⁴ 6d¹ 7s²
- Phase at STP
- Solid
- Density
- 20.45 g/cm³
- Melting point
- 917 K (643.9 °C)
- Boiling point
- 4273 K (3999.8 °C)
- Electronegativity
- 1.36
- Atomic radius
- 221 pm
- Ionization energy
- 6.266 eV
- Discovery
- 1940 · Edwin McMillan, Philip Abelson
Common uses
Nuclear reactors, research, neutron detectors
Did you know?
First transuranium element discovered and named after Neptune.
Experiment with the elements
Neptunium doesn't form any compounds in our lab yet, but the periodic table sandbox lets you combine dozens of other real elements into real compounds — water, table salt, ammonia and many more — with their true chemical formulas.