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Revision as of 15:00, 10 January 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Saving copy of the {{chembox}} taken from revid 470620432 of page Phosphoric_acid for the Chem/Drugbox validation project (updated: '').		Latest revision as of 13:27, 13 December 2024 edit DMacks (talk | contribs)Edit filter managers, Autopatrolled, Administrators186,052 edits Moving from Category:Hydrogen compounds to Category:Oxoacids using Cat-a-lot
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			{{Short description|Chemical compound (PO(OH)3)}}
	{{ambox | text = This page contains a copy of the infobox ({{tl|chembox}}) taken from revid of page ] with values updated to verified values.}}
			{{About|orthophosphoric acid|other acids commonly called "phosphoric acid" |Phosphoric acids and phosphates}}
	{{chembox
			{{Distinguish | Phosphorous acid}}
	| Verifiedfields = changed
			{{Use dmy dates|date=January 2020}}
	| verifiedrevid = 409759369
			{{chembox|Verifiedfields=changed
	| ImageFile = Phosphoric-acid-2D-dimensions.png
			|Watchedfields=changed
	| ImageSize = 180px
			|verifiedrevid=470622096
	| ImageName = Structural formula of phosphoric acid, showing dimensions
			|Name=
	| ImageFile1 = Phosphoric-acid-3D-balls.png
			|ImageFile=Phosphoric-acid-2D-dimensions.svg
	| ImageSize1 = 150px
			|ImageSize=150px
	| ImageName1 = Ball-and-stick model
			|ImageName=Structural formula of phosphoric acid, showing dimensions
	| IUPACName = trihydroxidooxidophosphorus<br/>phosphoric acid
			|ImageFileL1=Phosphoric-acid-3D-balls.png
	| OtherNames = Orthophosphoric acid
			|ImageSizeL1=120px
	| Section1 = {{Chembox Identifiers
			|ImageNameL1=Ball-and-stick model
			|ImageFileR1=Phosphoric-acid-3D-vdW.png
			|ImageSizeR1=120px
			|ImageNameR1=Space-filling model
			|IUPACName=Phosphoric acid
			|OtherNames=Orthophosphoric acid, hydrogen phosphate
			|SystematicName=
			|Section1={{Chembox Identifiers
	| PubChem = 1004		| PubChem = 1004
	| UNII_Ref = {{fdacite|correct|FDA}}		| UNII_Ref = {{fdacite|correct|FDA}}
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	| InChI = 1/H3O4P/c1-5(2,3)4/h(H3,1,2,3,4)		| InChI = 1/H3O4P/c1-5(2,3)4/h(H3,1,2,3,4)
	| InChIKey = NBIIXXVUZAFLBC-UHFFFAOYAI		| InChIKey = NBIIXXVUZAFLBC-UHFFFAOYAI
	| ChEBI_Ref = {{ebicite|changed|EBI}}		| ChEBI_Ref = {{ebicite|correct|EBI}}
	| ChEBI = 26078		| ChEBI = 26078
	| SMILES = OP(=O)(O)O		| SMILES = OP(=O)(O)O
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	| CASNo = 7664-38-2		| CASNo = 7664-38-2
	| CASNo_Ref = {{cascite|correct|CAS}}		| CASNo_Ref = {{cascite|correct|CAS}}
	| CASOther = <br/>16271-20-8 (hemihydrate)
	| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}		| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
	| ChemSpiderID = 979		| ChemSpiderID = 979
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	| UNNumber = 1805		| UNNumber = 1805
	| RTECS = TB6300000		| RTECS = TB6300000
			}}|Section2={{Chembox Properties
			| Formula = {{chem2|H3PO4}}
			| H=3|P=1|O=4
			| Appearance = Colorless solid
			| Odor = Odorless
			| Density = 1.6845 g/cm<sup>3</sup> (25&nbsp;°C, 85%),<ref name="Density 85%">{{Cite journal| author=Christensen, J. H.| author2=Reed, R. B. | year=1955| title=Design and Analysis Data—Density of Aqueous Solutions of Phosphoric Acid Measurements at 25&nbsp;°C.| journal=Ind. Eng. Chem.| volume=47 | issue=6 | pages=1277–1280| doi=10.1021/ie50546a061}}</ref> 1.834 g/cm<sup>3</sup> (solid)<ref name="Density solid">{{Cite web| url=https://cameochemicals.noaa.gov/chemical/4231| title=CAMEO Chemicals Datasheet – Phosphoric Acid| access-date=15 August 2019| archive-date=15 August 2019| archive-url=https://web.archive.org/web/20190815155917/https://cameochemicals.noaa.gov/chemical/4231| url-status=live}}</ref>
			| MeltingPtC = 42.35
			| MeltingPt_notes = anhydrous<ref name="Greenwood">{{cite journal |last1=Greenwood |first1=N. N. |last2=Thompson |first2=A. |title=701. The mechanism of electrical conduction in fused phosphoric and trideuterophosphoric acids |journal=Journal of the Chemical Society (Resumed) |date=1959 |pages=3485 |doi=10.1039/JR9590003485}}</ref><br><!--
			-->{{convert|29.32|C|F K}} ]<ref name="Ross"/>
			| BoilingPt = {{ubl|212&nbsp;°C (414&nbsp;°F)<ref name=chemspider>{{cite web|url=http://www.chemspider.com/Chemical-Structure.979.html|title=Phosphoric acid|website=www.chemspider.com|access-date=3 March 2020|archive-date=12 March 2020|archive-url=https://web.archive.org/web/20200312003851/http://www.chemspider.com/Chemical-Structure.979.html|url-status=live}}</ref>(only water evaporates)<ref>{{Cite journal|url=https://pubs.acs.org/doi/pdf/10.1021/ie50507a050|doi=10.1021/ie50507a050|title=Vapor Pressure of Phosphoric Acids|year=1952|last1=Brown|first1=Earl H.|last2=Whitt|first2=Carlton D.|journal=Industrial & Engineering Chemistry|volume=44|issue=3|pages=615–618}}</ref>
			}}
			| Solubility = {{ubl|392.2 g/(100 g) (−16.3&nbsp;°C)|369.4{{nbsp}}g/(100 mL) (0.5&nbsp;°C)|446 g/(100 mL) (15&nbsp;°C)<ref name=sioc>{{cite book|last1 = Seidell|first1 = Atherton|last2 = Linke|first2 = William F.|year = 1952|title = Solubilities of Inorganic and Organic Compounds|publisher = Van Nostrand|url = https://books.google.com/books?id=k2e5AAAAIAAJ|access-date = 2 June 2014|archive-date = 11 March 2020|archive-url = https://web.archive.org/web/20200311230632/https://books.google.com/books?id=k2e5AAAAIAAJ|url-status = live}}</ref>|548{{nbsp}}g/(100 mL) (20&nbsp;°C)<ref name=crc>Haynes, p. 4.80</ref>
			}}
			| SolubleOther = Soluble in ]
			| pKa = {{ubl|p''K''<sub>a1</sub> = 2.16<ref>Haynes, p. 5.92</ref>|p''K''<sub>a2</sub> = 7.20|p''K''<sub>a3</sub> = 12.32}}
			| ConjugateBase = ]
			| Viscosity = 2.4–9.4{{nbsp}}] (85% {{abbr|aq. soln.|aqueous solution}}) <br />147 cP (100%)
			| RefractIndex = {{ubl|1.3420 (8.8% w/w {{abbr|aq. soln.|aqueous solution}})<ref name="Refractive Index">{{Cite journal|author=Edwards, O. W.| author2=Dunn, R. L.|author3=Hatfield, J. D. |year=1964|title=Refractive Index of Phosphoric Acid Solutions at 25 C.|journal=J. Chem. Eng. Data|volume=9|issue=4|pages=508–509|doi=10.1021/je60023a010}}</ref>
			| 1.4320 (85% aq. soln) 25&nbsp;°C
			}}
			| VaporPressure = 0.03{{nbsp}}mmHg (20{{nbsp}}°C)<ref name=PGCH/>
			| MagSus = −43.8·10<sup>−6</sup>{{nbsp}}cm<sup>3</sup>/mol<ref>Haynes, p. 4.134</ref>
			| LogP = −2.15<ref name="chemsrc">{{Cite web|url=https://www.chemsrc.com/en/cas/7664-38-2_329226.html|title=phosphoric acid_msds|access-date=2 May 2018| archive-date=4 July 2017|archive-url=https://web.archive.org/web/20170704022858/http://www.chemsrc.com/en/cas/7664-38-2_329226.html| url-status=live}}</ref>
	}}		}}
	| Section2 = {{Chembox Properties		|Section3={{Chembox Structure
			| CrystalStruct = Monoclinic
	| Formula = H<sub>3</sub>PO<sub>4</sub>
			| MolShape = Tetrahedral
	| MolarMass = 98.00 g/mol
	| Appearance = white solid or colourless, viscous liquid (>42 °C)
	| Density = 1.885 g/mL (liquid)<br/>1.685 g/mL (85 % solution)<br/>2.030 g/mL (crystal at 25 °C)
	| MeltingPt = 42.35 °C (anhydrous)<br/>29.32 °C (hemihydrate)
	| BoilingPt = 158 °C (decomp)
	| Solubility = 5.48 g/mL
	| pKa = 2.148, 7.198, 12.375
	| Viscosity = 2.4–9.4 ] (85% aq. soln.)<br/>147 ] (100 %)
	}}		}}
	| Section7 = {{Chembox Hazards		|Section4={{Chembox Thermochemistry
			| Thermochemistry_ref=<ref>Haynes, p. 5.13</ref>
	| ExternalMSDS =
			| DeltaHf = −1271.7 kJ/mol
	| EUIndex = 015-011-00-6
			| DeltaGfree = −1123.6 kJ/mol
	| EUClass = Corrosive ('''C''')
			| Entropy = 150.8 J/(mol⋅K)
	| NFPA-H = 2
			| HeatCapacity =145.0 J/(mol⋅K)
			}}|Section5=|Section6=|Section7={{Chembox Hazards
			| GHSPictograms = {{GHS05}}<ref name="sigma">{{Sigma-Aldrich|id=466123|name=Phosphoric acid|access-date=9 May 2014}}</ref>
			| GHSSignalWord = Danger
			| HPhrases = {{H-phrases|290|314}}<ref name="sigma" />
			| PPhrases = {{P-phrases|280|305+351+338|310}}<ref name="sigma" />
			| ExternalSDS =
			| NFPA-H = 3
	| NFPA-R = 0		| NFPA-R = 0
	| NFPA-F = 0		| NFPA-F = 0
	| NFPA-O = COR		| NFPA-S =
	| RPhrases = {{R34}}
	| SPhrases = {{S1/2}} {{S26}} {{S45}}
	| FlashPt = Non-flammable		| FlashPt = Non-flammable
			| LD50 = 1530 mg/kg (rat, oral)<ref>{{IDLH|7664382|Phosphoric acid}}</ref>
			| IDLH = 1000 mg/m<sup>3</sup><ref name=PGCH>{{PGCH|0506}}</ref>
			| REL = TWA 1 mg/m<sup>3</sup> ST 3 mg/m<sup>3</sup><ref name=PGCH/>
			| PEL = TWA 1 mg/m<sup>3</sup><ref name=PGCH/>
			}}|Section8={{Chembox Related
			| OtherFunction = {{ubl
			| ]
			| ]
			| ]
			| ]
			| ]
			| ]
			}}
			| OtherFunction_label = ] ]s
			}}
	}}		}}
	| Section8 = {{Chembox Related
			'''Phosphoric acid''' (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless ]-containing ], and ] with the ] {{chem2|]3]]4}}. It is commonly encountered as an 85% ], which is a colourless, odourless, and non-] syrupy liquid. It is a major industrial chemical, being a component of many fertilizers.
	| OtherFunctn = ]<br/>]<br/>]<br/>]<br/>]<br/>]
	| Function = ] ]s
			The compound is an ]. Removal of all three {{chem2|H+}} ions gives the ] ion {{chem2|PO4(3−)}}. Removal of one or two protons gives ] ion {{chem2|H2PO4−}}, and the ] ion {{chem2|HPO4(2−)}}, respectively. Phosphoric acid forms ], called ]s.<ref name="Westheimer">{{Cite journal|last=Westheimer |first=F.H. |author-link=Frank Westheimer |title=Why nature chose phosphates |journal=] |volume=235 |issue=4793 |pages=1173–1178 (see pp. 1175–1176) |date=6 June 1987 |doi=10.1126/science.2434996 |bibcode=1987Sci...235.1173W|citeseerx=10.1.1.462.3441 |pmid=2434996 }}</ref>
	}}
	}}
			The name "orthophosphoric acid" can be used to distinguish this specific acid from other "]", such as ]. Nevertheless, the term "phosphoric acid" often means this specific compound; and that is the current ].
			=={{Anchor|Manufacture}}Production==
			Phosphoric acid is produced industrially by one of two routes, wet processes and dry.<ref>{{cite book |last1=Becker |first1=Pierre |title=Phosphates and phosphoric acid |date=1988 |publisher=Marcel Dekker |location=New York |isbn=978-0824717124}}</ref><ref>{{cite book |last1=Gilmour |first1=Rodney |title=Phosphoric acid: purification, uses, technology, and economics |date=2014 |publisher=CRC Press |location=Boca Raton |url=https://books.google.com/books?id=lDMTAgAAQBAJ&pg=PP1 |isbn=9781439895108 |pages=44–61}}</ref><ref>{{cite journal |last1=Jupp |first1=Andrew R. |last2=Beijer |first2=Steven |last3=Narain |first3=Ganesha C. |last4=Schipper |first4=Willem |last5=Slootweg |first5=J. Chris |title=Phosphorus recovery and recycling – closing the loop |journal=Chemical Society Reviews |date=2021 |volume=50 |issue=1 |pages=87–101 |doi=10.1039/D0CS01150A|pmid=33210686 |doi-access=free}}</ref>
			=== Wet process ===
			In the wet process, a phosphate-containing mineral such as calcium ] and ] are treated with ].<ref>{{Greenwood&Earnshaw2nd|pages=520–522}}</ref>
			:{{chem2|Ca5(PO4)3OH + 5 H2SO4 → 3 H3PO4 + 5 ] + H2O}}
			:{{Chem2|Ca5(PO4)3F + 5 H2SO4 → 3 H3PO4 + 5 ] + HF}}
			] (gypsum, {{Chem2|CaSO4}}) is a by-product, which is removed as ]. The ] (HF) gas is streamed into a ] producing ]. In both cases the phosphoric acid solution usually contains 23–33% {{chem2|P2O5}} (32–46% {{chem2|H3PO4}}). It may be concentrated to produce ''commercial-'' or ''merchant-grade'' phosphoric acid, which contains about 54–62% ] (75–85% {{chem2|H3PO4}}). Further removal of water yields ''superphosphoric acid'' with a {{chem2|P2O5}} concentration above 70% (corresponding to nearly 100% {{chem2|H3PO4}}). The phosphoric acid from both processes may be further purified by removing compounds of arsenic and other potentially toxic impurities.
			=== Dry process===
			To produce food-grade phosphoric acid, phosphate ore is first reduced with ] in an ], to give elemental ]. This process is also known as the thermal process or the electric furnace process. Silica is also added, resulting in the production of ] slag. Elemental phosphorus is distilled out of the furnace and burned with air to produce high-purity ], which is dissolved in water to make phosphoric acid.<ref>{{cite journal |doi=10.1021/acscentsci.0c00332|title=Let's Make White Phosphorus Obsolete |year=2020 |last1=Geeson |first1=Michael B. |last2=Cummins |first2=Christopher C. |journal=ACS Central Science |volume=6 |issue=6 |pages=848–860 |pmid=32607432 |pmc=7318074 }}</ref> The thermal process produces phosphoric acid with a very high concentration of {{chem2|P2O5}} (about 85%) and a low level of impurities.
			However, this process is more expensive and energy-intensive than the wet process, which produces phosphoric acid with a lower concentration of {{chem2|P2O5}} (about 26-52%) and a higher level of impurities. The wet process is the most common method of producing phosphoric acid for fertilizer use.<ref></ref> Even in China, where the thermal process is still used quite widely due to relatively cheap coal as opposed to the sulfuric acid, over 7/8 of phosphoric acid is produced with wet process.<ref>{{Cite journal |last=Minpeng |last2=Chen |last3=Fu |last4=Sun |last5=Xu |last6=Xia |last7=Ji-ning |title=The Phosphorus Flow in China : A Revisit from the Perspective of Production |journal=Global Environmental Research |volume=19 |issue=1 |pages=19-25 |s2cid=201655549 |url=https://airies.wikiplus.net/attach.php/6a6f75726e616c5f31392d31656e67/save/0/0/19_1-4.pdf}}</ref>
			== Purification ==
			Phosphoric acids produced from ] or thermal processes often requires purification. A common purification methods is liquid-liquid extraction, which involves the separation of phosphoric acids from water and other impurities using organic solvents, such as ] (TBP), ] (MIBK), or ]. Nanofiltration involves the use of a premodified nanofiltration membrane, which is functionalized by a deposit of a high molecular weight polycationic polymer of polyethyleneimines. Nanofiltration has been shown to significantly reduce the concentrations of various impurities, including cadmium, aluminum, iron, and rare earth elements. The laboratory and industrial pilot scale results showed that this process allows the production of food-grade phosphoric acid.<ref>{{cite journal |last1=Wet Process Phosphoric Acid Purification |title=Wet Process Phosphoric Acid Purification Using Functionalized Organic Nanofiltration Membrane |journal=Separations |date=2022 |volume=9 |issue=4 |page=100 |doi=10.3390/separations9040100 |doi-access=free }}</ref>
			Fractional crystallization can achieve highest purities typically used for semiconductor applications. Usually a static crystallizer is used. A static crystallizer uses vertical plates, which are suspended in the molten feed and which are alternatingly cooled and heated by a heat transfer medium. The process begins with the slow cooling of the heat transfer medium below the freezing point of the stagnant melt. This cooling causes a layer of crystals to grow on the plates. Impurities are rejected from the growing crystals and are concentrated in the remaining melt. After the desired fraction has been crystallized, the remaining melt is drained from the crystallizer. The purer crystalline layer remains adhered to the plates. In a subsequent step, the plates are heated again to liquify the crystals and the purified phosphoric acid drained into the product vessel. The crystallizer is filled with feed again and the next cooling cycle is started.<ref></ref>
			==Properties==
			===Acidic properties===
			In aqueous solution phosphoric acid behaves as a triprotic acid.
			:{{chem2|H3PO4 ⇌ H2PO4- + H+}}, p''K''<sub>a1</sub> = 2.14
			:{{chem2|H2PO4- ⇌ HPO4(2-) + H+}}, p''K''<sub>a2</sub> = 7.20
			:{{chem2|HPO4(2-) ⇌ PO4(3-) + H+}}, p''K''<sub>a3</sub> = 12.37
			The difference between successive ] values is sufficiently large so that salts of either monohydrogen phosphate, {{chem2|HPO4(2-)}} or dihydrogen phosphate, {{chem2|H2PO4-}}, can be prepared from a solution of phosphoric acid by adjusting the ] to be mid-way between the respective p''K''<sub>a</sub> values.
			===Aqueous solutions===
			Aqueous solutions up to 62.5% {{chem2|H3PO4}} are ], exhibiting freezing-point depression as low as -85°C. When the concentration of acid rises above 62.5% the freezing-point increases, reaching 21°C by 85% {{chem2|H3PO4}} (w/w; the ]). Beyond this the ] becomes complicated, with significant local maxima and minima. For this reason phosphoric acid is rarely sold above 85%, as beyond this adding or removing small amounts moisture risks the entire mass freezing solid, which would be a major problem on a large scale. A local maximum at 91.6% which corresponds to the ] 2H<sub>3</sub>PO<sub>4</sub>•H<sub>2</sub>O, freezing at 29.32°C.<ref>{{cite journal |last1=Ross |first1=William H. |last2=Jones |first2=Russell M. |title=The Solubility and Freezing-Point Curves of Hydrated and Anhydrous Orthophosphoric Acid |journal=Journal of the American Chemical Society |date=August 1925 |volume=47 |issue=8 |pages=2165–2170 |doi=10.1021/ja01685a015}}</ref><ref>{{cite web |title=Purified Phosphoric Acid H3PO4 Technical Information Bulletin |url=http://www.waterguardinc.com/files/90712047.pdf |publisher=] |access-date=11 February 2023}}</ref> There is a second smaller eutectic depression at a concentration of 94.75% with a freezing point of 23.5°C. At higher concentrations the freezing point rapidly increases. Concentrated phosphoric acid tends to ] before crystallization occurs, and may be relatively resistant to crystallisation even when stored below the freezing point.<ref name="Ross">{{Cite journal |last1=Ross |first1=Wm. H. |last2=Jones |first2=R. M. |last3=Durgin |first3=C. B. |date=October 1925 |title=The Purification of Phosphoric Acid by Crystallization. |url=https://pubs.acs.org/doi/abs/10.1021/ie50190a031 |journal=Industrial & Engineering Chemistry |language=en |volume=17 |issue=10 |pages=1081–1083 |doi=10.1021/ie50190a031 |issn=0019-7866}}</ref>
			===Self condensation===
			Phosphoric acid is commercially available as aqueous solutions of various concentrations, not usually exceeding 85%. If concentrated further it undergoes slow self-condensation, forming an equilibrium with ]:
			:{{chem2|2 H3PO4 <-> H2O + H4P2O7}}
			Even at 90% concentration the amount of pyrophosphoric acid present is negligible, but beyond 95% it starts to increase, reaching 15% at what would have otherwise been 100% orthophosphoric acid.<ref>{{Citation |last1=Korte |first1=Carsten |title=Phosphoric Acid and its Interactions with Polybenzimidazole-Type Polymers |date=2016 |url=http://link.springer.com/10.1007/978-3-319-17082-4_8 |work=High Temperature Polymer Electrolyte Membrane Fuel Cells |pages=169–194 |editor-last=Li |editor-first=Qingfeng |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-17082-4_8 |isbn=978-3-319-17081-7 |access-date=2023-02-12 |last2=Conti |first2=Fosca |last3=Wackerl |first3=Jürgen |last4=Lehnert |first4=Werner |editor2-last=Aili |editor2-first=David |editor3-last=Hjuler |editor3-first=Hans Aage |editor4-last=Jensen |editor4-first=Jens Oluf}}</ref>
			As the concentration is increased ] are formed, culminating in the formation of ].<ref>{{cite journal |last1=Jameson |first1=R. F. |title=151. The composition of the "strong" phosphoric acids |journal=Journal of the Chemical Society (Resumed) |date=1 January 1959 |pages=752–759 |doi=10.1039/JR9590000752}}</ref> It is not possible to fully dehydrate phosphoric acid to ], instead the polyphosphoric acid becomes increasingly polymeric and viscous. Due to the self-condensation, pure orthophosphoric acid can only be obtained by a careful fractional freezing/melting process.<ref name="Ross" /><ref name="Greenwood" />
			==Uses==
			{{also|Phosphorus#Food additive}}
			The dominant use of phosphoric acid is for ]s, consuming approximately 90% of production.<ref name=Ullmann>{{Ullmann|first1=Klaus|last1=Schrödter|first2=Gerhard|last2=Bettermann|first3=Thomas |last3=Staffel|first4=Friedrich|last4=Wahl|first5=Thomas|last5=Klein|first6=Thomas|last6=Hofmann|title=Phosphoric Acid and Phosphates|year=2008|doi=10.1002/14356007.a19_465.pub3}}</ref>
			{| class="wikitable"
			|-
			! Application
			! Demand (2006) in thousands of tons
			! Main phosphate derivatives
			|-
			| Soaps and detergents || 1836 || ]
			|-
			| Food industry || 309 || ] ({{chem2|Na5P3O10}}), ], ], ], ], ], ] ({{chem2|Na2HPO4}}), {{chem2|H3PO4}}
			|-
			| ] || 164 || SHMP, ], ], ] ({{chem2|NaH2PO4}}), DSP
			|-
			| ]s || 68 || ] ({{chem2|CaHPO4}}), IMP, ]
			|-
			| Other applications || 287 || ] ({{chem2|Na3P3O9}}), TCP, APP, DAP, ] ({{chem2|Zn3(PO4)2}}), ] ({{chem2|AlPO4}}), {{chem2|H3PO4}}
			|}
			Food-grade phosphoric acid (additive ]<ref name=fgovuk>{{cite web|url=http://www.food.gov.uk/policy-advice/additivesbranch/enumberlist#h_7|title=Current EU approved additives and their E Numbers|date=14 March 2012|publisher=Foods Standards Agency|access-date=22 July 2012|archive-date=21 August 2013|archive-url=https://web.archive.org/web/20130821045312/http://food.gov.uk/policy-advice/additivesbranch/enumberlist#h_7|url-status=live}}</ref>) is used to acidify foods and beverages such as various ]s and jams, providing a tangy or sour taste. The phosphoric acid also serves as a ].<ref>{{Cite web|title=Why is phosphoric acid used in some Coca‑Cola drinks?{{!}} Frequently Asked Questions {{!}} Coca-Cola GB|url=https://www.coca-cola.co.uk/our-business/faqs/why-is-phosphoric-acid-used-in-coca-cola-drinks-diet-coke-coke-zero|access-date=2021-08-31|website=www.coca-cola.co.uk|language=en-GB|archive-date=2 August 2021|archive-url=https://web.archive.org/web/20210802114054/https://www.coca-cola.co.uk/our-business/faqs/why-is-phosphoric-acid-used-in-coca-cola-drinks-diet-coke-coke-zero|url-status=live}}</ref> Soft drinks containing phosphoric acid, which would include ], are sometimes called ]s or phosphates. Phosphoric acid in soft drinks has the potential to cause dental erosion.<ref>{{Cite journal|title=Dietary advice in dental practice|journal=British Dental Journal|volume=193|issue=10|pages=563–568|date=23 November 2002|doi=10.1038/sj.bdj.4801628|pmid=12481178|last1=Moynihan|first1=P. J.|doi-access=free}}</ref> Phosphoric acid also has the potential to contribute to the formation of ], especially in those who have had kidney stones previously.<ref name=Qa2014>{{cite journal |last1= Qaseem |first1= A |last2= Dallas |first2= P |last3= Forciea |first3= MA |last4= Starkey |first4= M |last5= Denberg |first5= TD |display-authors= 4 |title= Dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults: A clinical practice guideline from the American College of Physicians |journal= ] |date= 4 November 2014 |volume= 161 |issue= 9 |pages= 659–67 |doi= 10.7326/M13-2908 |pmid=25364887|doi-access= |s2cid= 3058172 }}</ref>
			Specific applications of phosphoric acid include:
			* in anti-rust treatment by ] or ]
			* to prevent ] ] by means of the ] process
			* as an external standard for ]
			* in ]s
			* in ] production<ref>{{Cite journal | last1 = Toles | first1 = C. | last2 = Rimmer | first2 = S. | last3 = Hower | first3 = J. C. | doi = 10.1016/S0008-6223(96)00093-0 | title = Production of activated carbons from a washington lignite using phosphoric acid activation | journal = Carbon | volume = 34 | issue = 11 | pages = 1419 | year = 1996 | bibcode = 1996Carbo..34.1419T }}</ref>
			* in ] processing, to etch ] selectively with respect to ]<ref> {{Webarchive|url=https://web.archive.org/web/20120925075407/http://terpconnect.umd.edu/~browns/wetetch.html |date=25 September 2012 }} umd.edu.</ref>
			* in ] to etch ] selectively with respect to ]<ref name="Wolf">{{cite book |title =Silicon processing for the VLSI era: Volume 1 – Process technology |last = Wolf |first = S. |author2=R. N. Tauber |year=1986 |page=534 |publisher = Lattice Press |isbn=978-0-9616721-6-4}}</ref>
			* in ] to etch ]
			* as a pH adjuster in cosmetics and skin-care products<ref>{{cite web|publisher = Paula's Choice|title = Ingredient dictionary: P|work = Cosmetic ingredient dictionary|access-date = 16 November 2007|url = http://www.cosmeticscop.com/learn/cosmetic_dictionary.asp?id=21&letter=P|archive-url = https://web.archive.org/web/20080118084632/http://www.cosmeticscop.com/learn/cosmetic_dictionary.asp?id=21&letter=P|archive-date = 18 January 2008|df = dmy-all}}</ref>
			* as a sanitizing agent in the dairy, food, and brewing industries<ref>{{cite web|url=http://www.fivestarchemicals.com/wp-content/uploads/StarSanTech-HB2.pdf|title=Star San|publisher=Five Star Chemicals|access-date=17 August 2015|archive-date=8 February 2016|archive-url=https://web.archive.org/web/20160208134008/http://www.fivestarchemicals.com/wp-content/uploads/StarSanTech-HB2.pdf|url-status=live}}</ref>
			Phosphoric acid may also be used for ] (]) of metals like aluminium or for ] of steel products in a process called ].<ref>{{Cite web |date=February 2021 |title=Phosphates - Metal Finishing |url=https://phosphatesfacts.org/wp-content/uploads/2021/02/Phosphates-Metal-Finishing.pdf |publisher=Phospates for Americas}}</ref>
			== Safety ==
			Phosphoric acid is not a ]. However, at moderate concentrations phosphoric acid solutions are irritating to the skin. Contact with concentrated solutions can cause severe skin burns and permanent eye damage.<ref name=":0">{{Cite web|url=http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=345245&brand=ALDRICH&PageToGoToURL=http%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F345245%3Flang%3Den|title=Phosphoric Acid, 85 wt.% SDS|date=5 May 2016|website=Sigma-Aldrich|access-date=16 January 2017|archive-date=18 January 2017|archive-url=https://web.archive.org/web/20170118123759/http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=345245&brand=ALDRICH&PageToGoToURL=http%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F345245%3Flang%3Den|url-status=live}}</ref>
			A link has been shown between long-term regular cola intake and ] in later middle age in women (but not men).<ref>{{cite journal|vauthors=Tucker KL, Morita K, Qiao N, Hannan MT, Cupples LA, Kiel DP | title=Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study| journal=American Journal of Clinical Nutrition| volume=84| pages=936–942| issue = 4| date = 1 October 2006| pmid = 17023723 | doi=10.1093/ajcn/84.4.936| doi-access=free}}</ref>
			==See also==
			* Phosphate ]s, such as ] fertilizers
			* ]
			==References==
			{{Reflist|30em}}
			==Cited sources==
			*{{cite book | editor= Haynes, William M. | year = 2011 | title = CRC Handbook of Chemistry and Physics | edition = 92nd | publisher = ] | isbn = 978-1439855119| title-link = CRC Handbook of Chemistry and Physics }}
			==External links==
			{{Commons category|Phosphoric acid|lcfirst=yes}}
			*
			*
			{{Authority control}}
			{{Hydrogen compounds}}
			{{DEFAULTSORT:Phosphoric Acid}}
			]
			]
			]
			]
			]
			]
			]
			]
			]
			]