Chemical Element: thorium

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Chemical-Element Information

Symbol: Th
Atomic number: 90
Year discovered: 1828

Discovered by: Baron Jöns Jakob Berzelius (1779-1848), a Swedish chemist, who devised chemical symbols, determined atomic weights, contributed to the atomic theory, and discovered several new elements.

• Thorium was discovered by Berzelius, in 1828, in a mineral given to him by the Reverend Has Morten Thrane Esmark.
• In electronic devices thorium oxide is widely used as a source of primary electron emission.
• The advent of atomic energy, jet turbines, and rockets brought an unusual demand for new metals and alloys.
• Important alloys containing thorium were developed for improving the high-temperature strength of metals, in particular the magnesium base alloys.
• Thorium powder is relatively stable in air, but spontaneous combustion has occurred and the storage of large quantities is hazardous.
• In 1898, Marie Curie showed that thorium also produced radiations, and she coined the term radioactivity for the phenomenon, so that it can be said that both uranium and thorium are radioactive.

Name in other languages:

French: thorium

German: Thorium

Italian: torio

Spanish: torio

Information about other elements may be seen at this Chemical Elements List.

A special unit about words that include chemo-, chem- may be seen here.