Thorium |
| Symbol | Th |
|---|---|
| Latin name | Thorium |
| Atomic number | 90 |
| Period | 7 |
| Element category | Inner transition elements |
| Relative atomic mass | 232.0381 |
| Group | IV.B |
| Electronegativity | 1.3 |
| Oxidation numbers | 4 |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f0 6d2 7s2 |
| Density [g/cm3] | 11.72 |
| State | Solid |
| Melting point [°C] | 1750 |
| Boiling point [°C] | 4500 |
| Thermal conductivity [W m-1K-1] | 54 |
| Heat capacity [J K-1g-1] | 0.113 |
| Discovery | 1828 |
| Hardness [Mohs scale] | 3 |
| Vickers hardness [MPa] | 350 |
| Brinell hardness [MPa] | 400 |
| Young's modulus [GPa] | 79 |
| Electrical conductivity [S m-1] | 6.7 · 106 |
| Shear modulus [GPa] | 31 |
| 1.st ionization energy [eV] | 6.08 |
| 2.nd ionization energy [eV] | 11.504 |
| 3.rd ionization energy [eV] | 20.003 |
| Stable isotopes | 0 |
| Unstable isotopes | 12 |