Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. The most stable isotope, 232Th, has a half-life of 14. 05 billion years, or about the age of the universe. Thorium was discovered in 1828 by the Norwegian amateur mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jacob Berzelius.
About Thorium in brief
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. The most stable isotope, 232Th, has a half-life of 14. 05 billion years, or about the age of the universe. Thorium was discovered in 1828 by the Norwegian amateur mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jacob Berzelius, who named it after Thor, the Norse god of thunder. It is estimated to be over three times as abundant as uranium in the Earth’s crust, and is chiefly refined from monazite sands as a by-product of extracting rare-earth metals. It has been suggested as a replacement for uranium as nuclear fuel in nuclear reactors, and several thorium reactors have been built. Other uses for thorium include heat-resistant ceramics, aircraft engines, and in light bulbs. In the second half of the 20th century, thorium was replaced in many uses due to concerns about its radioactivity. It was also used as an alloying element in TIG welding electrodes but is slowly being replaced in the field with different compositions. The properties of thorium vary widely depending on the degree of impurity in the sample. The major impurity is usually thorium dioxide, which can be studied in at least milligram quantities, and usually about tenth of a tenth of the weight of the purest thorium specimens. The melting point of 1750 °C is above both those of actinium and protactinium.
There is a new downward trend in melting points from thorium to plutonium, where the number of f electrons increases from about 0. 4 to about 6: trend is due to increasing hybridisation of the 5f and 6d orbitals and the formation of complex crystal structures. Among actinides up to californium, the highest boiling points and second-lowest density is thorium. Thoriam is nearly half as dense as uranium and plutonium and is harder than both. It becomes superconductive below 1. 4 K. It can be cold-rolled, swaged, and drawn. Pure thorium is very ductile and, as normal for metals, can be rolled into sheets and pulled into wire. At room temperature, Thorium metal has a face-centred cubic crystal structure; it has two other forms, one at high temperature and one atHigh pressure. Thorium has a bulk modulus of 54 GPa, about the same as tin’s. Aluminium’s is 75. 2GPa; copper’s 137. 8 GPa; and mild steel’s is 160–169 GPa. Thorium is about as hard as soft steel, so when heated it can be Rolled into sheets and pull into wire, and can be pulled into sheets, and it becomes superconductor below 1 4°C. It is also used to strengthen magnesium, coating tungsten wire in electrical equipment, controlling the grain size of tungststen in electric lamps, high-temperature crucibles, in glasses and in glasses.
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This page is based on the article Thorium published in Wikipedia (as of Nov. 10, 2020) and was automatically summarized using artificial intelligence.
