Introduction to Thorium
Thorium is a chemical element represented by the symbol Th and atomic number 90 on the periodic table. It is a naturally occurring, slightly radioactive metal. In its pure form, thorium is a silvery-white metal that tarnishes black when exposed to air, forming thorium dioxide. It belongs to the actinide series, a group of metallic elements found at the bottom of the periodic table.
Discovery and Naming
The element thorium was discovered in 1828 by the Swedish chemist Jöns Jacob Berzelius. He isolated the element from a mineral that had been found on an island off the coast of Norway. Berzelius named the new element ‘thorium’ in honour of Thor, the Norse god of thunder, who is a significant figure in Norse mythology.
Quick Facts About Thorium
- Thorium is found in small amounts in most rocks and soils. It is particularly abundant in certain minerals like monazite sands, which are found in significant quantities along the coastal regions of Kerala, India.
- It is a radioactive element, meaning its atomic nucleus is unstable and releases energy and particles over time. The most common isotope, Thorium-232, has a very long half-life, meaning it decays very slowly over billions of years.
- Historically, thorium was used in the manufacture of gas mantles, which produced bright light when heated by a flame. Its high melting point makes it useful in some alloys.
- Thorium has potential as a nuclear fuel. When bombarded with neutrons, Thorium-232 can be converted into Uranium-233, which is fissile and can be used to generate nuclear energy.
- Thorium is denser than lead and has a high melting point of 1750°C (3182°F), making it a refractory metal.