Protactinium
From The Encyclopedia of Earth
November 8, 2006, 10:29 pm
| Topics: |
| Previous Element: Thorium Next Element: Uranium |
| |
| 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 | |
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Sources: |
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