Praseodymium

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59

Pr

140.91
Physical Properties
Color silvery-white
Phase at Room Temp. solid
Density (g/cm3) 6.475
Hardness (Mohs) ---
Melting Point (K) 1204.2
Boiling Point (K) 3293
Heat of Fusion (kJ/mol) 11.3
Heat of Vaporization (kJ/mol) 331
Heat of Atomization (kJ/mol) 356
Thermal Conductivity (J/m sec K) 12.5
Electrical Conductivity (1/mohm cm) 14.706
Source Monazite (phosphate), bastnaesite
Atomic Properties
Electron Configuration [Xe]6s24f3
Number of Isotopes 45 (1 natural)
Electron Affinity (kJ/mol) 50
First Ionization Energy (kJ/mol) 523.2
Second Ionization Energy (kJ/mol) 1018
Third Ionization Energy (kJ/mol) 2086
Electronegativity 1.13
Polarizability (Å3) 28.2
Atomic Weight 140.91
Atomic Volume (cm3/mol) 21.8
Ionic Radius2- (pm) ---
Ionic Radius1- (pm) ---
Atomic Radius (pm) 182
Ionic Radius1+ (pm) ---
Ionic Radius2+ (pm) ---
Ionic Radius3+ (pm) 113
Common Oxidation Numbers +3
Other Oxid. Numbers +2, +4
Abundance
In Earth's Crust (mg/kg) 9.2x100
In Earth's Ocean (mg/L) 6.4x10-7
In Human Body (%) ---
Regulatory / Health
CAS Number 7440-10-0
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). Praseodymium. Retrieved from http://www.eoearth.org/view/article/51cbeea97896bb431f6996e1

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