This was first attributed to the conversion of tooth enamel hydroxyapatite into the more durable fluorapatite, but studies on pre-fluoridated teeth refuted this hypothesis, and current theories involve fluoride aiding enamel growth in small caries. [91], The substitution of hydrogen atoms in an alkane by progressively more fluorine atoms gradually alters several properties: melting and boiling points are lowered, density increases, solubility in hydrocarbons decreases and overall stability increases. [198] The largest application is in electrical insulation since PTFE is an excellent dielectric. Fluorine is a chemical element with the symbol F and atomic number 9. [63][79][183], At least 17,000 metric tons of fluorine are produced each year. "Certain nuclei can for many purposes be thought of as spinning round an axis like the Earth or like a top. Specifically, he would be know that the reaction of, as yet unseen, fluorine with hydrogen would be highly explosive and spontaneous. Fluorine and sodium acetate produce an explosive reaction involving the formation of diacetyl peroxide, [Mellor 2, Supp. In general the spin endows them with angular momentum and with a magnetic moment; the first because of their mass, the second because all or part of their electric charge may be rotating with the mass. Perfluorocarbons,[note 16] in which all hydrogen atoms are substituted, are insoluble in most organic solvents, reacting at ambient conditions only with sodium in liquid ammonia. [62][74][75] The composition of fluorite was later determined to be calcium difluoride. Located in the second period of the table (row 2), fluorine is the first element in the family of halogen gases. Fluorine is a highly reactive element that is used in processing nuclear fuel, in producing plastics and as a glass etching solution. Fluorine-18 Fluorodeoxyglucose. Only in 1886 did French chemist Henri Moissan isolate elemental fluorine using low-temperature electrolysis, a process still employed for modern production. [134] Carbon tetrafluoride is tetrahedral and inert;[note 15] its group analogues, silicon and germanium tetrafluoride, are also tetrahedral[135] but behave as Lewis acids. Small amounts of fluorine may be beneficial for bone strength, but the latter has not been definitively established. Fluorine substitution, usually of a single atom or at most a trifluoromethyl group, is a robust modification with effects analogous to fluorinated pharmaceuticals: increased biological stay time, membrane crossing, and altering of molecular recognition. [63][193] Surfactants are a minor application but generate over $1 billion in annual revenue. Period 3 and heavier nonmetals can form hypervalent fluorides. The rest of the fluorite is converted into corrosive hydrogen fluoride en route to various organic fluorides, or into cryolite, which plays a key role in aluminium refining. Partial and complete lung filling have been considered, though only the former has had any significant tests in humans. Learn more about fluoride and its benefits and risks. Liquid fluorine is a very low temperature substance, comparable with liquid oxygen, and is highly toxic and corrosive as well. Fluorine attracts electrons more readily than any other element. The transition from β- to α-fluorine is more exothermic than the condensation of fluorine, and can be violent. They point out that fluorine is a deadly poison and that fluorides can be toxic as well. [143] Many of them are powerful sources of fluorine atoms, and industrial applications using chlorine trifluoride require precautions similar to those using fluorine. [91][195], Halogenated refrigerants, termed Freons in informal contexts,[note 18] are identified by R-numbers that denote the amount of fluorine, chlorine, carbon, and hydrogen present. Most had no symptoms, but about 30% had stomach pains. The latter crystallizes at −220 °C (−364 °F) and is transparent and soft, with the same disordered cubic structure of freshly crystallized solid oxygen,[42][note 2] unlike the orthorhombic systems of other solid halogens. [156] It is almost non-existent in nature, but is used in artificial compounds. The reaction can be explosive under the right conditions [3]: H 2 (g) + F 2 (g) 2 HF (g) Reaction of fluorine with metals/metal ions. [194], About 30% of agrichemicals contain fluorine,[208] most of them herbicides and fungicides with a few crop regulators. [205], Fluorosurfactants are small organofluorine molecules used for repelling water and stains. Dwell time in the body varies greatly by species, with half-lives of days in rodents, and years in humans. [63][189] Alongside its role as an additive in materials like enamels and welding rod coats, most acidspar is reacted with sulfuric acid to form hydrofluoric acid, which is used in steel pickling, glass etching and alkane cracking. [46][47][note 3], Only one isotope of fluorine occurs naturally in abundance, the stable isotope 19F. [120][121][122] Rhenium heptafluoride, the only characterized metal heptafluoride, is a low-melting molecular solid with pentagonal bipyramidal molecular geometry. It's been nicknamed "the tiger of chemistry" because it has killed so many chemists. [262] It is a volatile liquid due to the presence of hydrogen bonding (while the other hydrohalic acids are gases). The ratio of the angular momentum to magnetic moment is called the gyromagnetic ratio. [34][35][36] Heavier halogens[37] react readily with fluorine as does the noble gas radon;[38] of the other noble gases, only xenon and krypton react, and only under special conditions. [290][291][294], Fluorine F Atomic Number: 9 Atomic Weight: 18.9984032 Melting Point: 53.63 KBoiling Point: 85.03 KSpecific mass: 0.001696 g/cm3 Electronegativity: 3.98, Chlorine Cl Atomic Number: 17 Atomic Weight: 35.453 Melting Point: 172.31 K Boiling Point: 239.11 KSpecific mass: 0.003214 g/cm3 Electronegativity: 3.16, Bromine Br Atomic Number: 35 Atomic Weight: 79.904 Melting Point: 266.05 K Boiling Point: 332.0 KSpecific mass: 3.122 g/cm3 Electronegativity: 2.96, Iodine I Atomic Number: 53 Atomic Weight: 126.90447 Melting Point: 386.65 K Boiling Point: 475.4 KSpecific mass: 4.93 g/cm3 Electronegativity: 2.66, Astatine At Atomic Number: 85 Atomic Weight: [210] Melting Point: 575.15 K Boiling Point: 610 KSpecific mass: 7 g/cm3 Electronegativity: 2.2. [252] The most common is fluoroacetate, which is used as a defense against herbivores by at least 40 plants in Africa, Australia and Brazil. ", "Overview on the History of Organofluorine Chemistry from the Viewpoint of Material Industry", Essential Nutrients in Drinking Water (Draft), "Community Water Fluoridation and Caries Prevention: A Critical Review", "Global Fluorochemicals Market to Exceed 2.6 Million Tons by 2015, According to a New Report by Global Industry Analysts, Inc", "Global Fluorspar Market to Reach 5.94 Million Metric Tons by 2017, According to New Report by Global Industry Analysts, Inc", "Fluoropolymers Market is Poised to Grow at a CAGR of 6.5% & to Reach $9,446.0 Million by 2016 – New report by MarketsandMarkets", "The Long and the Short of Perfluorinated Replacements", "A Half-century of Community Water Fluoridation in the United States: Review and Commentary", "Undersŏkning om fluss-spat och dess syra", "Use of Fluorine-18 Fluoro-2-deoxy-D-glucose Positron Emission Tomography in Assessing the Process of Tuberculous Spondylitis", "Epidemiologic Evidence on the Health Effects of Perfluorooctanoic Acid (PFOA)", "Basil Valentine, A Seventeenth Century Hoax", "Fluorine – A Vital Element in the Medicine Chest", "Anhydrous Ammonia: (MSDS) Material Safety Data Sheet", "Fluorochemicals Market is Expected to Reach USD 21.5 Billion Globally by 2018: Transparency Market Research", United States Environmental Protection Agency, "Emerging Contaminants – Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA)", "Phaseout of HCFCs (Class II Ozone-Depleting Substances)", "Honeywell Invests $300m in Green Refrigerant", "Unnecessary use of Fluoroquinolone Antibiotics in Hospitalized Patients", "A Systematic Review of the Efficacy and Safety of Fluoridation", Ergocalciferol and Cholecalciferol (Vitamin D), https://en.wikipedia.org/w/index.php?title=Fluorine&oldid=1010594019, Biology and pharmacology of chemical elements, Short description is different from Wikidata, All articles that may have off-topic sections, Wikipedia articles that may have off-topic sections from November 2020, Articles with Encyclopædia Britannica links, Creative Commons Attribution-ShareAlike License, fluorine is borne out on convection currents arising from fusion in, This page was last edited on 6 March 2021, at 08:09. [124], Hydrogen and fluorine combine to yield hydrogen fluoride, in which discrete molecules form clusters by hydrogen bonding, resembling water more than hydrogen chloride. [note 8] Isolation of elemental fluorine was hindered by the extreme corrosiveness of both elemental fluorine itself and hydrogen fluoride, as well as the lack of a simple and suitable electrolyte. [22] Some solid nonmetals (sulfur, phosphorus) react vigorously in liquid fluorine. REASON FOR CITATION * Fluorine is on the Hazardous Substance List because it is regulated by OSHA and cited by ACGIH, DOT, NIOSH, [19][20] Conversely, bonds to other atoms are very strong because of fluorine's high electronegativity. Fluorine will burn all sorts of compounds and elements including water, copper, gold, and steel. Fluorine taken from fluorite is an extremely reactive chemical. Among the elements, fluorine ranks 24th in universal abundance and 13th in terrestrial abundance. [133], Boron trifluoride is planar and possesses an incomplete octet. It is a gas, never occurring in its free state. It acts by attacking the lungs, airways and eyes, effectively blinding and suffocating the victim. Natural organofluorines have been found in microorganisms and plants[66] but not animals. Fluorine is one of the halogens. It reacts with calcium and magnesium in the blood leading to hypocalcemia and possible death through cardiac arrhythmia. [241] Because fluorocarbons do not normally mix with water, they must be mixed into emulsions (small droplets of perfluorocarbon suspended in water) to be used as blood. Fluorine is a yellowish gas at room temperature and is very dangerous. [69][70][note 5] He penned the Latin word fluorēs (fluor, flow) for fluorite rocks. [79][91][92], Large-scale production of elemental fluorine began during World War II. Fluorine gas is a deadly poison. ", Or perhaps from as early as 1670 onwards; Partington. Fluorides tend to be dangerous only in large doses. [273] Malfunctioning water fluoridation equipment is another cause: one incident in Alaska affected almost 300 people and killed one person. How Dangerous Is Fluoride To Your Health? Important HCFCs include R-22, chlorodifluoromethane, and R-141b. [23] Hydrogen sulfide[23] and sulfur dioxide[24] combine readily with fluorine, the latter sometimes explosively; sulfuric acid exhibits much less activity, requiring elevated temperatures. It functions as a Lewis acid and combines with Lewis bases like ammonia to form adducts. Although expensive (comparable to pharmaceuticals at $200–2000 per kilogram), they yielded over $1 billion in annual revenues by 2006; Scotchgard alone generated over $300 million in 2000. g/cm3 Electronegativity: ? If the paper weren't laid out in complete grammatical sentences and published in JACS, you'd swear it was the work of a violent lunatic. [86][88] In 1886, after 74 years of effort by many chemists, Moissan isolated elemental fluorine. It tends to form acids easily, which means it eats through whatever early chemists used to contain it. [55] This is because stellar nucleosynthesis processes bypass fluorine, and any fluorine atoms otherwise created have high nuclear cross sections, allowing further fusion with hydrogen or helium to generate oxygen or neon respectively. [200][201], The chemically resistant (but expensive) fluorinated ionomers are used as electrochemical cell membranes, of which the first and most prominent example is Nafion. [244] These substances can aid endurance athletes and are banned from sports; one cyclist's near death in 1998 prompted an investigation into their abuse. The Element Fluorine. [27] Carbon dioxide and carbon monoxide react at or just above room temperature,[28] whereas paraffins and other organic chemicals generate strong reactions:[29] even completely substituted haloalkanes such as carbon tetrachloride, normally incombustible, may explode. Fluorine is toxic for humans and very corrosive. [123] Metal fluorides with more fluorine atoms are particularly reactive. Used for air conditioning systems, propellants and solvents, their production was below one-tenth of this peak by the early 2000s, after widespread international prohibition. Fluorotelomers, which have some unfluorinated carbon atoms near the functional group, are also regarded as perfluorinated. Unlike the other hydrohalic acids, which are strong, hydrofluoric acid is a weak acid at low concentrations. One particularly unpleasant combination, hydrogen fluoride, destroys tissues on contact, particularly the corneas of the eyes. Fluorine atoms have nine electrons, one fewer than neon, and electron configuration 1s 2s 2p : two electrons in a filled inner shell and seven in an outer shell requiring one more to be filled. Graphite combines with fluorine above 400 °C (750 °F) to produce non-stoichiometric carbon monofluoride; higher temperatures generate gaseous fluorocarbons, sometimes with explosions. We're going to show you one of its most volatile explosions, and explain how it nearly killed one of the first researchers to work with it. [136][137] The pnictogens form trifluorides that increase in reactivity and basicity with higher molecular weight, although nitrogen trifluoride resists hydrolysis and is not basic. Today, there are still explosions due to the accidental mixing of hydrogen and fluorine. Sodium reacts with fluorine forming sodium fluoride [3]: 2 Na (s) + F 2 (g) 2 NaF (s) [268][269][270] Hydrofluoric acid absorption requires further medical treatment; calcium gluconate may be injected or administered intravenously. [63][196] Chlorofluorocarbons (CFCs) like R-11, R-12, and R-114 once dominated organofluorines, peaking in production in the 1980s. Films from two different fluoropolymers replace glass in solar cells. [184], The largest application of fluorine gas, consuming up to 7,000 metric tons annually, is in the preparation of UF6 for the nuclear fuel cycle. Many current antidepressants receive this same treatment, including the selective serotonin reuptake inhibitors: citalopram, its isomer escitalopram, and fluvoxamine and paroxetine. [85][note 7], Initial studies on fluorine were so dangerous that several 19th-century experimenters were deemed "fluorine martyrs" after misfortunes with hydrofluoric acid. If fluorine is absorbed too frequently, it can cause teeth decay, osteoporosis and harm to kidneys, bones, nerves and muscles. [63] Fluorine is also used in the synthesis of organic fluorides, but its reactivity often necessitates conversion first to the gentler ClF3, BrF3, or IF5, which together allow calibrated fluorination. [218][221] The benefits of fluoridation have lessened, possibly due to other fluoride sources, but are still measurable in low-income groups.
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