Neptunium
93
Np
Group
n/a
Period
7
Block
f
Protons
Electrons
Neutrons
93
93
144
General Properties
Atomic Number
93
Atomic Weight
[237]
Mass Number
237
Category
Actinides
Color
Silver
Radioactive
Yes
Named after the planet Neptune
Crystal Structure
Simple Orthorhombic
History
Neptunium was the first synthetic transuranium element of the actinide series to be discovered.
Neptunium was first produced by Edwin McMillan and Philip H. Abelson in 1940 at Berkeley Radiation Laboratory of the University of California.
The team produced the neptunium isotope 239Np by bombarding uranium with slow moving neutrons.
Neptunium was first produced by Edwin McMillan and Philip H. Abelson in 1940 at Berkeley Radiation Laboratory of the University of California.
The team produced the neptunium isotope 239Np by bombarding uranium with slow moving neutrons.
Electrons per shell
2, 8, 18, 32, 22, 9, 2
Electron Configuration
[Rn] 5f4 6d1 7s2
Neptunium is obtained as a by-product from nuclear reactors
Physical Properties
Phase
Solid
Density
20.45 g/cm3
Melting Point
910.15 K | 637 °C | 1178.6 °F
Boiling Point
4273.15 K | 4000 °C | 7232 °F
Heat of Fusion
10 kJ/mol
Heat of Vaporization
335 kJ/mol
Specific Heat Capacity
-
Abundance in Earth's crust
n/a
Abundance in Universe
n/a
CAS Number
7439-99-8
PubChem CID Number
n/a
Atomic Properties
Atomic Radius
155 pm
Covalent Radius
190 pm
Electronegativity
1.36 (Pauling scale)
Ionization Potential
6.2657 eV
Atomic Volume
11.62 cm3/mol
Thermal Conductivity
0.063 W/cm·K
Oxidation States
3, 4, 5, 6, 7
Applications
Neptunium is used mainly for research purposes.
When bombarded with neutrons 237Np is used to produce 238Pu which is used for spacecraft generators and terrestrial navigation beacons.
237Np is used in devices for detecting high-energy neutrons.
When bombarded with neutrons 237Np is used to produce 238Pu which is used for spacecraft generators and terrestrial navigation beacons.
237Np is used in devices for detecting high-energy neutrons.
Neptunium is harmful due to its radioactivity
Isotopes
Stable Isotopes
-Unstable Isotopes
225Np, 226Np, 227Np, 228Np, 229Np, 230Np, 231Np, 232Np, 233Np, 234Np, 235Np, 236Np, 237Np, 238Np, 239Np, 240Np, 241Np, 242Np, 243Np, 244Np