CAS Number54037-57-9
PubChem CIDna
Atomic Radius-
Atomic Volume-
Atomic Weight[269]
Boiling Point-
Bulk Modulus
CategoryTransition metals
Crystal Structure
Covalent Radius134
Electrical Resistivity
Electron Configuration[Rn] 5f14 6d6 7s2
Electrons per shell2, 8, 18, 32, 32, 14, 2
Heat of Fusionna
Heat of Vaporizationna
Ionization Potential-
Magnetic Ordering
Magnetic Susceptibility
Mass Number108
Melting Point-
Atomic Number269
Oxidation States8
Poisson Ratio
Shear Modulus
Specific Heat Capacity-
Thermal Conductivity-
Van der Waals radius
Young's Modulus
Abundance in Earth's crustna
Abundance in Universena
Hs Hassium 108 (278) 8 7 d 108 [Rn] 5f14 6d6 7s2 2 8 18 32 32 14 2 None Unknown 1 1.11 h 1.39h AlphaEmission TransitionMetal, Metal, Radioactive, Synthetic HES-i-em Synthetic radioactive metal. It has no significant commercial applications. Formed by the bombardment of lead-208 with iron-58. VQ8cZoA0tiU Hassium
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 108 1984 Peter Armbruster, Gottfried Münzenber and their co-workers. Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany. The origin of the name is the Latin word "Hassias" meaning "Hess", the German state.

Isotopes of Thorium

Standard Atomic Weight

Stable Isotopes

Unstable Isotopes

263Hs 264Hs 265Hs 266Hs 267Hs 268Hs 269Hs 270Hs 271Hs 272Hs 273Hs 274Hs 275Hs 276Hs 277Hs

Thorium is highly radioactive
Thorium fuel research is continuing in several countries including the USA and India
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.