Neptunium
Symbol
Np
Atomic Number
93
Atomic Weight
237.048
Element Classification
Discovered By
E.M. McMillan, P.H. Abelson
Discovery Date
1940 (United States)
Name Origin
Named for the planet Neptune.
Density(g/cc)
20.25
Melting Point
913
Boiling Point(K)
4175
Appearance
Silvery metal
Atomic Radius(pm)
130
Atomic Volume(cc/mol)
21.1
Covalent Radius(pm)
n/a
Ionic Radius
95 (+4e) 110 (+3e)
Specific Heat
n/a
Fusion Heat
(9.6)
Evaporation Heat(kj/mol)
336
Thermal Conductivity(@25°C W/m K)
(6.3)
Debye Temperature
n/a
Pauling Negativity Number
1.36
First Ionizing Energy(kj/mol)
n/a
Oxidation States
6, 5, 4, 3
Electronic Configuration
[Rn] 5f4 6d1 7s2
Lattice Structure
Orthorhombic(ORC)
Lattice Constant
4.720
Lattice C/A Ratio
n/a
