Basic Information

Name: Neptunium 
Symbol: Np 
Atomic Number: 93 
Atomic Mass: (237.0) amu 
Melting Point: 640.0 °C (913.15 K, 1184.0 °F) 
Boiling Point: 3902.0 °C (4175.15 K, 7055.6 °F) 
Number of Protons/Electrons: 93 
Number of Neutrons: 144 
Classification: Rare Earth 
Crystal Structure: Orthorhombic 
Density @ 293 K: 20.45 g/cm3 
Color: Unknown
Date of Discovery: 1940 
Discoverer: E.M. McMillan 
Name Origin: After the planet Neptune 
Uses: No uses known 
Obtained From: Man-made