It is given by the ratio of the shear stress to the shear strain. A measure of how difficult it is to compress a substance. It is given by the ratio of the pressure on a body to the fractional decrease in volume.
A measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system. This Site has been carefully prepared for your visit, and we ask you to honour and agree to the following terms and conditions when using this Site. Copyright of and ownership in the Images reside with Murray Robertson. The RSC has been granted the sole and exclusive right and licence to produce, publish and further license the Images.
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Jump to main content. Periodic Table. Glossary Allotropes Some elements exist in several different structural forms, called allotropes. Glossary Group A vertical column in the periodic table. Fact box. Glossary Image explanation Murray Robertson is the artist behind the images which make up Visual Elements. Appearance The description of the element in its natural form. Biological role The role of the element in humans, animals and plants.
Natural abundance Where the element is most commonly found in nature, and how it is sourced commercially. Uses and properties. Image explanation. The imagery used here is that associated with Thor, the Norse god connected with thunder.
Thorium is an important alloying agent in magnesium, as it imparts greater strength and creep resistance at high temperatures. Thorium oxide is used as an industrial catalyst.
Thorium can be used as a source of nuclear power. It is about three times as abundant as uranium and about as abundant as lead, and there is probably more energy available from thorium than from both uranium and fossil fuels. India and China are in the process of developing nuclear power plants with thorium reactors, but this is still a very new technology.
Thorium dioxide was formerly added to glass during manufacture to increase the refractive index, producing thoriated glass for use in high-quality camera lenses. Biological role. Thorium has no known biological role. It is toxic due to its radioactivity.
Natural abundance. Thorium is found as the minerals thorite, uranothorite and thorianite. It is also found in monazite, which is the most important commercial source. Several methods are used to produce the metal, such as reducing thorium oxide with calcium or electrolysis of the fluoride. Help text not available for this section currently. Elements and Periodic Table History.
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 by Gerhard Schmidt and confirmed by Marie Curie. Thorium, like uranium, survives on Earth because it has isotopes with long half-lives, such as the predominant one, thorium, whose half life is 14 billion years.
Atomic data. Glossary Common oxidation states The oxidation state of an atom is a measure of the degree of oxidation of an atom.
Oxidation states and isotopes. Glossary Data for this section been provided by the British Geological Survey. Relative supply risk An integrated supply risk index from 1 very low risk to 10 very high risk. Recycling rate The percentage of a commodity which is recycled.
Substitutability The availability of suitable substitutes for a given commodity. Reserve distribution The percentage of the world reserves located in the country with the largest reserves. Political stability of top producer A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators. Political stability of top reserve holder A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators.
Supply risk. Relative supply risk 7. Young's modulus A measure of the stiffness of a substance. Shear modulus A measure of how difficult it is to deform a material. Bulk modulus A measure of how difficult it is to compress a substance.
Vapour pressure A measure of the propensity of a substance to evaporate. Pressure and temperature data — advanced. Listen to Thorium Podcast Transcript :. You're listening to Chemistry in its element brought to you by Chemistry World , the magazine of the Royal Society of Chemistry.
Frequently after more spectacular chemistry demonstrations, the scientist on stage will warn the audience 'not to try this at home'. Instead, he and his co-workers performed many groundbreaking experiments in the kitchen of his flat in the corner of Nybrogatan and Riddargatan in Stockholm. In , for example, Berzelius isolated a new element from a mineral sent to him from the Swedish mining town of Falun and named it thorium after the Scandinavian god of thunder, Thor.
Only to realise a few years later that he was wrong and what he though was a new element was in fact yttrium phosphate. However, in , by then long since world famous and credited with discovering three other elements, he received a strange mineral sample from the reverend Hans Esmark in Norway.
Thorium is used as an alloying agent to improve magnesium 's strength at high temperatures. Thorium is also used to coat tungsten filaments used in electronic devices, such at television sets. When bombarded with neutrons , thorium becomes thorium, which eventually decays into uranium through a series of beta decays. Uranium is a fissionable material and can be used as a nuclear fuel.
Thorium oxide ThO 2 , one of thorium's compounds, has many uses. It is primarily used in a type of lantern mantel known as a Welsbach mantle. Thorium oxide is also used to make glass with a high index of refraction that is used to make high quality camera lenses. In , however, it was determined that the mineral was in fact yttrium phosphate.
The mineral contained nearly 60 percent of an unknown element, which took over the name thorium; the mineral was named thorite. The mineral also contained many known elements, including iron, manganese, lead, tin, and uranium, according to Chemicool. Berzelius isolated thorium by first mixing thorium oxide found in the mineral with carbon to create thorium chloride, which was then reacted with potassium to yield thorium and potassium chloride, according to Chemicool. Gerhard Schmidt, a German chemist, and Marie Curie, a Polish physicist, independently discovered that thorium was radioactive in within a couple months of each other, according to Chemicool.
Schmidt is often credited with the discovery. Ernest Rutherford, a New Zealand physicist, and Frederick Soddy, an English chemist, discovered that thorium decays at a fixed rate into other elements, also known as the half-life of an element, according to Los Alamos National Laboratory.
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