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Fluorine (fluorine) is a non-metallic chemical element with chemical symbol F and atomic number 9. Fluorine is one of the halogen elements, belonging to the periodic Ⅶ A group, which is located in the second cycle in the periodic table. The elemental substance of fluorine is F2, which is a yellowish and highly toxic gas. Fluorine is highly corrosive and chemically active. It is one of the most oxidizing substances and can even react with some inert gases under certain conditions. Fluorine is a key element in specialty plastics, rubber and freezers (chlorofluoroalkane). Because of the special chemical properties of fluoride, fluorine chemistry plays an important role in the history of chemical development.

As early as 1529, the German mineralogist Agricola recorded that miners had already used fluorite, a fluorine-containing ore, as a casting flux for steelmaking.

Fluorite (Fluorite) is also called fluorite. A common mineral in nature, which can be symbiotic with many other minerals, is produced in many places in the world, and there are 5 effective varieties. Equiaxed crystal system, the main composition is CaF fluoride. Crystallized into octahedrons and cubes. The crystal has glass luster, bright color, brittleness, Morse hardness of 4 and melting point of 1360 ℃, which has the property of complete cleavage. Some of the samples can glow under the conditions of friction, heating, ultraviolet radiation and so on.

The mineral comes from volcanic magma. In the process of magma cooling, the gas-water solution separated by magma contains fluorine. In the process of solution rising along the crack, the fluorine ion in the gas-water solution combines with the calcium ion in the surrounding rock to form calcium fluoride. Fluorite is formed after cooling and crystallization.

In 1670 Schwahad, a German glasser, occasionally exposed fluorite to sulfuric acid to produce a gas that covered his glasses with a mist that he realized could corrode glass. So he protected some parts of the glass with wax so that others were corroded by the gas, so that the glass surface formed a pattern. The patterned glass was appreciated by the court and royal family, and the technology of etching glass with hydrogen fluoride made him a lot of money.

In 1780 Carl Wilhelm Scheler, a Swedish chemist, was fascinated by this phenomenon and hypothesized that the gas produced by the contact of fluorite with sulfuric acid might contain some unknown, more active element. For this reason, he carried out this reaction experiment many times. Due to the lack of chemical detection methods at that time, chemists often used nose-smelling and mouth-tasting methods to identify him. As a result, he died prematurely due to poisoning at the age of 43. Persistence makes chemists pursue knowledge one after another.

In 1836, the Irish Knox brothers failed to use chlorine to react with mercuric fluoride to produce elemental fluorine, but they suffered from poisoning for a long time. Lauet, a Belgian chemist, then repeated the experiment and lost his life as a result of hydrogen fluoride poisoning.

Fleming, a student of Lauet, summed up the failure experience of his predecessors and believed that fluorine was so active that it was difficult to succeed with chemical methods. In 1885, he used the existing electrolysis method to do experiments, but the dry gas hydrogen fluoride did not conduct electricity, and his experiments also failed, but accumulated a great deal of experience.

The research work was passed on to Fleming's student Henry Mauasan (1852-1907), who continued to study the subject. The young Mauvassan saw that the research project of preparing elemental fluorine had baffled so many chemists. Instead of being discouraged, he made up his mind to overcome this difficulty. Mosang himself designed a platinum U-tube device, which connected the platinum electrode with current electrolysis of "anhydrous hydrofluoric acid". In order to prevent the formation of high temperature gas corrosion container, he also used refrigerant to cool the experimental device. the resulting yellowish gas is his dream of fluorine.

Henry Mowassan was the first chemist to prepare many new fluorides. He prepared gaseous fluoromethane, fluoroethane, and isobutyl fluorine. Many fluorocarbons were prepared by the reaction of carbon with fluorine in 1890. the most striking one is tetrafluoromethane CF4, which is prepared by the interaction of fluorine with methane or chloroform or carbon tetrachloride with a boiling point of-15 ℃. Mauvassan's work can be said to have made him a forerunner in the 20th century in the synthesis of a series of fluorocarbons (freons) that act as efficient refrigerants.

Gaseous sulfur hexafluoride was prepared in 1900. Its chemical properties are very similar to those of nitrogen. When heated to a higher temperature, it will not decompose or react with molten alkali. Sulfur hexafluoride has become an excellent gas insulating material because of its inertia and chemical stability. He also synthesized platinum, alkaline earth metal, iridium, magnesium fluoride, iodine pentafluoride and nitryl fluoride successively. He compiled the results of the study of fluorine into a book "Fluorine and its compounds", which is an important material for studying the preparation and properties of fluorine and its compounds.

Mauvassan discovered the fluorine device and his Nobel Prize certificate, Henry Mowasan, "knowing that there is a tiger in the mountain," he was poisoned four times in the experiment in order to devote himself to science. He was awarded the Nobel Prize in chemistry in 1906 for this. Because of the serious damage to his health, he died in the second year after winning the award at the age of 54.

It has been more than a hundred years since the discovery of fluorine, and many fluorine-containing compounds have made great contributions to human life and production, such as the excellent performance of polytetrafluoroethylene is an indispensable material for atomic energy and aerospace technology, and refrigerant Freon. Fluorine-containing fibers, coatings, anticancer agents, lithium hexafluorophosphate and other power storage materials in lithium-ion batteries have played an important role. We should have deep respect for the pioneers of fluorine chemistry led by Mosang.

Comprehensive from "Apocalypse of Scientific and technological Innovation: anecdotes of Masters of Innovation and Invention", Baidu Encyclopedia author: Jinyong some pictures come from the network copyright belongs to the original author ★ book introduction ★

Apocalypse of scientific and technological innovation: anecdotes of masters of innovation and invention, edited by Jinyong Tsinghua University Press, this is a popular book about innovation. In this book, the author gives a popular explanation of his understanding and understanding of innovation to the public in an "approachable" way, which is interspersed with hundreds of stories of masters of innovation and invention, transforming what should be abstract, obscure and complex content into vivid and vivid pictures, from which innovative passion and concise enlightenment are conveyed. In the current era of great change in building an innovative country, and at a turning point when our country is moving from an economic power to an economic power, the author hopes that this book will be beneficial to young readers who advance bravely in the torrent, explorers of various industries wandering in the threshold of invention and creation, as well as leading cadres and civil servants eager to create a new situation of change. A brief introduction to ★ authors ★

Jin Yong, Professor, Department of Chemical Engineering, Tsinghua University; Academician of the Chinese Academy of Engineering; graduated from Ural University of Technology in the Soviet Union in 1959, taught at University of Science and Technology of China from 1959 to 1973, and taught at Tsinghua University from 1973 to 2019; majoring in chemical reaction engineering and eco-industrial engineering, he is enthusiastic about science popularization in recent years. He is currently the executive director of the Chinese Society of Chemical Engineering and the China Institute of particles, the vice chairman of the Chinese Society of Ecological Economics, the director of the Professional Committee of Industrial Ecological Economics and Technology, and the consultant of the Institute of Industrial Innovation and Finance of Tsinghua University. he was a member of the discipline review panel and convener of the degree committee of the State Council, and a professional adviser to the third to sixth Beijing Municipal Government. He has won National Science and Technology Progress Award, National Invention Award, American Society of Chemical Engineers (AIChE) Chair Professor Award, National May Day Labor Medal, National Model worker, National Outstanding teacher Award, Sinorama Engineering Science and Technology Award, and "praise 2016 Top Ten Science Communication figures in China". This article comes from Wechat official account: Origin Reading (ID:tupydread), author: Jin Yong, Editor: Zhang Runxin

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