Neptunium
From The Encyclopedia of Earth
November 8, 2006, 10:17 pm
| Topics: |
| Previous Element: Uranium Next Element: Plutonium |
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| 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 | |
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Sources: |
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