Editing Fluoride (section)

==Applications==
{{See also|Fluorochemical industry|Biological aspects of fluorine|Fluorine}}
Fluoride salts and hydrofluoric acid are the main fluorides of industrial value.

===Organofluorine chemistry===
{{main|Organofluorine chemistry}}
Organofluorine compounds are pervasive. Many drugs, many polymers, refrigerants, and many inorganic compounds are made from fluoride-containing reagents. Often fluorides are converted to hydrogen fluoride, which is a major reagent and precursor to reagents. Hydrofluoric acid and its anhydrous form, [[hydrogen fluoride]], are particularly important.<ref name="Aigueperse">{{cite encyclopedia|last1=Aigueperse|first1=Jean|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|last2=Mollard|first2=Paul|last3=Devilliers|first3=Didier|last4=Chemla|first4=Marius|last5=Faron|first5=Robert|last6=Romano|first6=René|last7=Cuer|first7=Jean Pierre|year=2000|doi=10.1002/14356007.a11_307|isbn=978-3527306732|chapter=Fluorine Compounds, Inorganic}}</ref>

===Production of metals and their compounds===
The main uses of fluoride, in terms of volume, are in the production of cryolite, Na<sub>3</sub>AlF<sub>6</sub>. It is used in [[aluminium smelting]]. Formerly, it was mined, but now it is derived from hydrogen fluoride. Fluorite is used on a large scale to separate slag in steel-making. Mined [[fluorite]] (CaF<sub>2</sub>) is a commodity chemical used in steel-making.  [[Uranium hexafluoride]] is employed in the purification of uranium isotopes.

===Cavity prevention===
{{main|Fluoride therapy|Water fluoridation}}
[[Image:Sodium fluoride tablets.jpg|thumb|right|Sodium fluoride sold in tablets for cavity prevention.]]
Fluoride-containing compounds, such as [[sodium fluoride]] or [[sodium monofluorophosphate]] are used in topical and systemic [[fluoride therapy]] for preventing [[Dental caries|tooth decay]]. They are used for [[water fluoridation]] and in many products associated with [[oral hygiene]].<ref name="mcdonagh2000">{{cite journal|author1=McDonagh M. S. |author2=Whiting P. F. |author3=Wilson P. M. |author4=Sutton A. J. |author5=Chestnutt I. |author6=Cooper J. |author7=Misso K. |author8=Bradley M. |author9=Treasure E. |author10=Kleijnen J. |year=2000 |title=Systematic review of water fluoridation |journal=[[British Medical Journal]] |volume=321 |issue=7265| pages=855–859|doi=10.1136/bmj.321.7265.855 |pmid=11021861|pmc=27492}}</ref> Originally, sodium fluoride was used to fluoridate water; [[hexafluorosilicic acid]] (H<sub>2</sub>SiF<sub>6</sub>) and its salt [[sodium hexafluorosilicate]] (Na<sub>2</sub>SiF<sub>6</sub>) are more commonly used additives, especially in the United States. The fluoridation of water is known to prevent tooth decay<ref>{{cite journal |vauthors=Griffin SO, Regnier E, Griffin PM, Huntley V |title=Effectiveness of fluoride in preventing caries in adults |journal=J. Dent. Res. |volume=86 |issue=5 |pages=410–5 |year=2007 |pmid=17452559 |doi=10.1177/154405910708600504|hdl=10945/60693 |s2cid=58958881 |hdl-access=free }}</ref><ref>{{cite journal |author1=Winston A. E. |author2=Bhaskar S. N. |title=Caries prevention in the 21st century |journal=J. Am. Dent. Assoc. |volume=129 |issue=11 |pages=1579–87 |date=1 November 1998 |pmid=9818575 |url=http://jada.ada.org/cgi/pmidlookup?view=long&pmid=9818575 |archive-url=https://archive.today/20120715143950/http://jada.ada.org/cgi/pmidlookup?view=long&pmid=9818575 |url-status=dead |archive-date=15 July 2012 |doi=10.14219/jada.archive.1998.0104 }}</ref> and is considered by the U.S. [[Centers for Disease Control and Prevention]] to be "one of 10 great public health achievements of the 20th century".<ref>{{cite web|title=Community Water Fluoridation|url=https://www.cdc.gov/fluoridation/|publisher=Centers for Disease Control and Prevention|access-date=10 March 2016}}</ref><ref>{{cite web|title=Ten Great Public Health Achievements in the 20th Century|url=https://www.cdc.gov/about/history/tengpha.htm|publisher=Centers for Disease Control and Prevention|access-date=10 March 2016|archive-url=https://web.archive.org/web/20160313072852/http://www.cdc.gov/about/history/tengpha.htm|archive-date=2016-03-13|url-status=dead}}</ref> In some countries where large, centralized water systems are uncommon, fluoride is delivered to the populace by fluoridating table salt. Fluoridation of water has its critics {{crossreference|(see [[Water fluoridation controversy]])}}.<ref>{{cite journal |author=Newbrun E |title=The fluoridation war: a scientific dispute or a religious argument? |journal=Journal of Public Health Dentistry |volume=56 |issue=5 Spec No |pages=246–52 |year=1996 |pmid=9034969 |doi=10.1111/j.1752-7325.1996.tb02447.x}}</ref> Fluoridated [[toothpaste]] is in common use. [[Meta-analysis]] show the efficacy of 500 ppm fluoride in toothpastes.<ref>{{Cite journal|last1=Walsh|first1=Tanya|last2=Worthington|first2=Helen V.|last3=Glenny|first3=Anne-Marie|last4=Marinho|first4=Valeria Cc|last5=Jeroncic|first5=Ana|date=March 4, 2019|title=Fluoride toothpastes of different concentrations for preventing dental caries|journal=Cochrane Database of Systematic Reviews|volume=3|issue=3|pages=CD007868|doi=10.1002/14651858.CD007868.pub3|issn=1469-493X|pmc=6398117|pmid=30829399}}</ref><ref>{{Cite web|title=Remineralization of initial carious lesions in deciduous enamel after application of dentifrices of different fluoride concentrations|url=https://www.springermedizin.de/remineralization-of-initial-carious-lesions-in-deciduous-enamel-/8679072|access-date=2021-02-24|website=springermedizin.de|language=de}}</ref> However, no beneficial effect can be detected when more than one fluoride source is used for daily oral care.<ref>{{Cite journal|last1=Hausen|first1=H.|last2=Kärkkäinen|first2=S.|last3=Seppä|first3=L.|date=February 2000|title=Application of the high-risk strategy to control dental caries|url=https://pubmed.ncbi.nlm.nih.gov/10634681/|journal=Community Dentistry and Oral Epidemiology|volume=28|issue=1|pages=26–34|doi=10.1034/j.1600-0528.2000.280104.x|issn=0301-5661|pmid=10634681}}</ref>{{request quotation|date=August 2021}}

===Laboratory reagent===
Fluoride salts are commonly used in biological assay processing to [[enzyme inhibitor|inhibit]] the activity of [[phosphatases]], such as [[serine]]/[[threonine]] phosphatases.<ref>{{cite journal |vauthors=Nakai C, Thomas JA |title=Properties of a phosphoprotein phosphatase from bovine heart with activity on glycogen synthase, phosphorylase, and histone |journal=J. Biol. Chem. |volume=249 |issue=20 |pages=6459–67 |year=1974 |doi=10.1016/S0021-9258(19)42179-0 |pmid=4370977 |url=http://www.jbc.org/cgi/pmidlookup?view=long&pmid=4370977|doi-access=free }}</ref> Fluoride mimics the [[nucleophile|nucleophilic]] [[hydroxide]] ion in these enzymes' active sites.<ref>{{cite journal |vauthors=Schenk G, Elliott TW, Leung E |title=Crystal structures of a purple acid phosphatase, representing different steps of this enzyme's catalytic cycle |journal=BMC Struct. Biol. |volume=8 |page=6 |year=2008 |pmid=18234116 |doi=10.1186/1472-6807-8-6 |pmc=2267794|display-authors=etal |doi-access=free }}</ref> [[Beryllium fluoride]] and [[aluminium fluoride]] are also used as phosphatase inhibitors, since these compounds are structural mimics of the [[phosphate]] group and can act as analogues of the [[transition state]] of the reaction.<ref>{{cite journal |vauthors=Wang W, Cho HS, Kim R |title=Structural characterization of the reaction pathway in phosphoserine phosphatase: crystallographic "snapshots" of intermediate states |journal=J. Mol. Biol. |volume=319 |issue=2 |pages=421–31 |year=2002 |pmid=12051918 |doi=10.1016/S0022-2836(02)00324-8 |display-authors=etal}}</ref><ref>{{cite journal |vauthors=Cho H, Wang W, Kim R |title=BeF(3)(-) acts as a phosphate analog in proteins phosphorylated on aspartate: structure of a BeF(3)(-) complex with phosphoserine phosphatase |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=98 |issue=15 |pages=8525–30 |year=2001 |pmid=11438683 |doi=10.1073/pnas.131213698 |pmc=37469|bibcode = 2001PNAS...98.8525C |display-authors=etal|doi-access=free }}</ref>