Protactinium

Previous Element: Thorium

Next Element: Uranium
103

Pa

231.04
Physical Properties
Color silvery
Phase at Room Temp. solid
Density (g/cm3) 15.37
Hardness (Mohs) ---
Melting Point (K) 1873.2
Boiling Point (K) 4500
Heat of Fusion (kJ/mol) 16.7
Heat of Vaporization (kJ/mol) 481
Heat of Atomization (kJ/mol) 527
Thermal Conductivity (J/m sec K) ---
Electrical Conductivity (1/mohm cm) ---
Source Synthetic (U-235 decay)
Atomic Properties
Electron Configuration [Rn]7s25f26d1
Number of Isotopes 30 (1 natural)
Electron Affinity (kJ/mol) ---
First Ionization Energy (kJ/mol) 568
Second Ionization Energy (kJ/mol) ---
Third Ionization Energy (kJ/mol) ---
Electronegativity 1.5
Polarizability (Å3) 25.4
Atomic Weight 231.04
Atomic Volume (cm3/mol) 15
Ionic Radius2- (pm) ---
Ionic Radius1- (pm) ---
Atomic Radius (pm) 163
Ionic Radius1+ (pm) ---
Ionic Radius2+ (pm) ---
Ionic Radius3+ (pm) 118
Common Oxidation Numbers +5
Other Oxid. Numbers +3, +4
Abundance
In Earth's Crust (mg/kg) 1.5x10-6
In Earth's Ocean (mg/L) 5.0x10-11
In Human Body (%) ---
Regulatory / Health
CAS Number 7440-13-3
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). Protactinium. Retrieved from http://www.eoearth.org/view/article/51cbeeab7896bb431f699829

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