Neptunium

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Next Element: Plutonium
93

Np

237.05
Physical Properties
Color silvery
Phase at Room Temp. solid
Density (g/cm3) 20.45
Hardness (Mohs) ---
Melting Point (K) 913.2
Boiling Point (K) 4175
Heat of Fusion (kJ/mol) 9.5
Heat of Vaporization (kJ/mol) 336
Heat of Atomization (kJ/mol) ---
Thermal Conductivity (J/m sec K) 6.3
Electrical Conductivity (1/mohm cm) ---
Source Synthetic
Atomic Properties
Electron Configuration [Rn]7s25f46d1
Number of Isotopes 23 (0 natural)
Electron Affinity (kJ/mol) ---
First Ionization Energy (kJ/mol) 597
Second Ionization Energy (kJ/mol) ---
Third Ionization Energy (kJ/mol) ---
Electronegativity 1.3
Polarizability (Å3) 24.8
Atomic Weight 237.05
Atomic Volume (cm3/mol) 11.6
Ionic Radius2- (pm) ---
Ionic Radius1- (pm) ---
Atomic Radius (pm) 155
Ionic Radius1+ (pm) ---
Ionic Radius2+ (pm) 124
Ionic Radius3+ (pm) 115
Common Oxidation Numbers +5
Other Oxid. Numbers +3, +4, +6, +7
Abundance
In Earth's Crust (mg/kg) ---
In Earth's Ocean (mg/L) ---
In Human Body (%) ---
Regulatory / Health
CAS Number 7439-99-8
OSHA Permissible Exposure Limit (PEL) No limits
OSHA PEL Vacated 1989 No limits
NIOSH Recommended Exposure Limit (REL) No limits
Sources:
University of Wisconsin General Chemistry
Mineral Information Institute
Jefferson Accelerator Laboratory
EnvironmentalChemistry.com
 
Glossary

Citation

(2006). Neptunium. Retrieved from http://www.eoearth.org/view/article/51cbee807896bb431f6984f2

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