Symbol	Np	Atomic radius: pm	-	Fusion: kJ/Mole	3.20
Name	Neptunium	Ionic radius: pm	(+5)75	Boiling point: °C	-
Atomic number	93	Electron affinity	-	Melting point: °C	644
Atomic weight	237.0	1st  ion potential	6.27	Specific Heat Cap: J/(g K)	-
Classification	Trans metal	Natural form	Solid	Thermal Cond: W/(cm K)	0.06
Configuration	[Rn]5f46d17s2	Crystal structure	Ortho	Electrical Cond	0.00822
Oxidation states	3,4,5,6	Density	20.2	Abundance: mg/kg-crust	Synthetic
Electronegativity	1.3	Vaporization: kJ/Mole	337.0
Edwin M.McMillan and Philip H. Abelson first found neptunium in 1940 after uranium had been bombarded by neutrons.			Uses - a component in neutron detection instruments