Thorium (Th)
Grey radioactive metallic element. Belongs to actinoids. Found in monazite sand in Brazil, India and the US. Thorium-232 has a half-life of 1.39x10^10 years. Can be used as a nuclear fuel for breeder reactors. Thorium-232 captures slow Neutrons and breeds uranium-233. Discovered by Jons J. Berzelius in 1829.
| Atomic Number | 90 |
|---|---|
| Atomic Weight | 232.0377 |
| Mass Number | 232 |
| Group | |
|---|---|
| Period | 7 |
| Block | f |
| Protons | 90 p+ |
|---|---|
| Neutrons | 142 n0 |
| Electrons | 90 e- |
Properties
| Atomic Radius | 180 pm
|
|---|---|
| Atomic Volume | 19.8 cm³/mol
|
| Covalent Radius | 175 pm
|
| Metallic Radius | |
| Ionic Radius | 94 pm
|
| Crystal Radius | 108 pm
|
| Van der Waals radius |
245.00000000000003 pm
|
| Density | 11.7 g/cm³
|
| Boiling Point | 5,060 K
|
| Melting Point | 2,028 K
|
| Electrons per shell | 2, 8, 18, 32, 18, 10, 2 |
| Electronegativity |
1.3
|
| Electrophilicity | |
| Proton Affinity | |
| Electron Affinity | |
| Ionization Potential | 6.3067 eV/particle
|
| Heat of Vaporization | 513.7 kJ/mol
|
| Heat of Fusion | 16.11 kJ/mol
|
| Heat of Formation | 602 kJ/mol
|
| Molar Heat Capacity | 27.32 J/(mol K)
|
| Specific Heat Capacity | 0.118 J/(g⋅K)
|
| Thermal Conductivity | |
| Gas Basicity | |
| Dipole Polarizability | 217 a₀
|
| C6 Dispersion Coefficient | |
| Oxidation States | 2, 3, 4 |
| Color | Silver
|
| Crystal Structure | Face Centered Cubic (FCC) |
| Lattice Constant | 5.08 Å
|
| Bulk Modulus | |
| Electrical Resistivity | |
| Electron Configuration | [Rn] 6d2 7s2 |
| Magnetic Ordering | |
| Magnetic Susceptibility | |
| Phase | Solid |
| Poisson Ratio | |
| Shear Modulus | |
| Young's Modulus | |
| Allotropes | |
| Alternate Names | |
| Adiabatic Index | |
| Appearance | |
| Electric Conductivity | |
| Critical Pressure | |
| Critical Temperature | |
| Curie Point | |
| Electrical | |
| Hardness | |
| Magnetic Susceptibility | |
| Magnetic | |
| Neel Point | |
| Neutron Cross Section | |
| Neutron Mass Absorption | |
| Gas Phase | |
| Quantum Numbers | |
| Refractive Index | |
| Space Group | |
| Speed of Sound | |
| Superconducting Point | |
| Thermal Expansion | |
| Valence Electrons | |
| Classification | |
| Category | Actinides, Actinides |
| CAS Group | |
| IUPAC Group | |
| Glawe Number | 34 |
| Mendeleev Number | 16 |
| Pettifor Number | 47 |
| Geochemical Class | rare earth & related |
| Goldschmidt Class | litophile |
| Radioactivity | |
| Radioactive | Yes ☢️ |
| Decay Mode | |
| Half-Life | |
| Lifetime | |
| Abundance | |
| Abundance in Earth's crust | 9.6 mg/kg
|
| Abundance in Oceans | 0.000001 mg/L
|
| Abundance in Human Body | |
| Abundance in Meteor | |
| Abundance in Sun | |
| Abundance in Universe | 4×10-8% |
Isotopes of Thorium
Stable Isotopes
230Th 232Th
Unstable Isotopes
209Th 210Th 211Th 212Th 213Th 214Th 215Th 216Th 217Th 218Th 219Th 220Th 221Th 222Th 223Th 224Th 225Th 226Th 227Th 228Th 229Th 231Th 233Th 234Th 235Th 236Th 237Th 238Th
History
Thorium was discovered by Jöns Jacob Berzelius in 1828, in Stockholm, Sweden. Thorium was first observed to be radioactive in 1898, independently, by Polish-French physicist Marie Curie and German chemist Gerhard Carl Schmidt. The crystal bar process was discovered by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925 to produce high-purity metallic thorium. Named after Thor, Scandinavian god of war
| Discoverers | Jöns Berzelius |
|---|---|
| Discovery Location | Sweden |
| Discovery Year | 1828 |
| Name Origin | Named for Thor, Norse god of thunder. |
Thorium is highly radioactive
Thorium fuel research is continuing in several countries including the USA and India
Uses
Thorium is used to coat tungsten filaments in light bulbs. It is also used in its oxide form in gas tungsten arc welding to increase the high-temperature strength of tungsten electrodes and improve arc stability. Thorium-magnesium alloys are used in the aerospace industry for aircraft engines. Used in making strong alloys. Also in ultraviolet photoelectric cells. It is a common ingredient in high-quality lenses. Bombarded with neutrons make uranium-233, a nuclear fuel.
Sources
Found in various minerals like monazite and thorite.