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Thorium (Th): Actinides

Thorium (Th)

What is Thorium?

Thorium (Th), radioactive chemical element of the actinoid series of the periodic table, atomic number 90; it is a useful nuclear reactor fuel. Thorium was discovered (1828) by Swedish chemist Jöns Jacob Berzelius. It is silvery white but turns gray or black on exposure to air. It is about half as abundant as lead and is three times more abundant than uranium in Earth’s crust. Thorium is commercially recovered from the mineral monazite and occurs also in other minerals such as thorite and thorianite. Thorium metal has been produced in commercial quantities by reduction of the tetrafluoride (ThF4) and dioxide (ThO2) and by electrolysis of the tetrachloride (ThCl4). The element was named for the Norse god Thor. Continue reading from Encyclopedia Britannica

The History

In 1829, Jöns Jakob Berzelius of the Royal Karolinska Institute, Stockholm extracted thorium from a rock specimen sent to him by an amateur mineralogist who had discovered it near Brevig and realised that it had not previously been reported. The mineral turned out to be thorium silicate, and it is now known as thorite. Berzelius even produced a sample of metallic thorium by heating thorium fluoride with potassium, and confirmed it as a new metal. The radioactivity of thorium was first demonstrated in 1898 by Gerhard Schmidt and confirmed by Marie Curie. Continue reading from Royal Society of Chemistry

Thorium Facts

Thorium dioxide has the highest melting point of all known oxides. Thorium is about as abundant as lead and at least three times as abundant as uranium. Thorium had been used since 1885 in gas mantles, which provide the light in gas lamps, according to Los Alamos. Due to its radioactivity, the element has been replaced by other nonradioactive rare-earth elements. The most stable isotope of thorium, Th-232, has a half-life of 14 billion years. Thorium itself is not used for nuclear fuel, but it is used to create the artificial uranium isotope uranium-233. Continue reading from Live Science

Chart of Elemental Properties for Thorium

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