Properties | |
| Atomic Number: | 83 |
| Atomic Weight: | 208.9804 |
| Electron Configuration (at ground state): | 1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p3 |
| Oxidation States (Bold most stable): | +3, +5 |
| Boiling Point (K): | 1837 |
| Melting Point (K): | 544.59 |
| Density (at 300K -- g/cm3): | 9.75 |
| Atomic Volume (at 300K -- cm3/mol) | 21.3 |
| Number of stable isotopes: | 1 |
| Number of natural radioactive isotopes: | 3 |
| Mass Number (Bold naturally occurring) -- Half-Life -- Disintigration Type: |
207 -- 83 years -- orbital electron capture 208 -- 3.7 x 105 years -- orbital electron capture 210 -- 5.01 days -- beta particle (electron) emission, alpha particle emission 210 -- 3 x 106 years -- alpha particle emission |
| Covalent Radius (Å): | 1.46 |
| Atomic Radius (Å): | 1.70 |
| First Ionization Potential (V): | 7.289 |
| Electronegativity (Pauling's): | 2.02 |
| Specific Heat Capacity (at 300K -- J g-1 K-1): | 0.122 |
| Heat of Vaporization (kJ/mol): | 179 |
| Heat of Fusion (kJ/mol): | 11.0 |
Electrical Conductivity (at 293K for polycrystalline material -- 106  -1 cm-1): |
0.9 |
| Thermal Conductivity (at 300K -- W m-1 K-1): | 7.87 |
| Crystal Structure: |  Rhombohedral |
| Acid-Base Properties: |  Slightly acidic |