Properties | |
| Atomic Number: | 84 |
| Atomic Weight: | 209 |
| Electron Configuration (at ground state): | 1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p4 |
| Oxidation States (Bold most stable): | +4, +2, +6 |
| Melting Point (K): | 527 |
| Density (at 300K -- g/cm3): | 9.3 |
| Atomic Volume (at 300K -- cm3/mol) | 22.70 |
| Number of natural radioactive isotopes: | 7 |
| Mass Number (Bold naturally occurring) -- Half-Life -- Disintigration Type: |
208 -- 2.90 years -- alpha particle emission 209 -- 102 years -- alpha particle emission 210 -- 22.3 years -- alpha particle emission |
| Covalent Radius (Å): | 1.53 |
| Atomic Radius (Å): | 1.67 |
| First Ionization Potential (V): | 8.42 |
| Electronegativity (Pauling's): | 2.0 |
| Heat of Vaporization (kJ/mol): | 120 |
| Heat of Fusion (kJ/mol): | 13 |
Electrical Conductivity (at 293K for polycrystalline material -- 106  -1 cm-1): |
0.7 |
| Thermal Conductivity (at 300K -- W m-1 K-1): | 20 |
| Crystal Structure: |  Monoclinic |
| Acid-Base Properties: |  Amphoteric |