Symbol
Np
Atomic Number
93
Atomic Mass
237.0482
Protons
93
Neutrons
144
Electrons
93
Type
Actinide
Isotopes
Neptunium-237
Discovery Year
1940
Discovered By
Edwin McMillan, Philip H. Abelson
Group
3
Period
7
Boiling Point
4155°F
Melting Point
640°F
Electron Configuration
[Rn] 7s² 6d⁄
Density (g/cm³)
20.25
Crystal Structure
Orthorhombic
Magnetism
Paramagnetic
Abundance in Earth's Crust
Trace
Phase at Room Temperature
Solid