PhosphateAphosphate(PO43) asaninorganicchemical isasalt of phosphoric acid. In organic chemistry, a phos-phate, or organophosphate, is an ester of phosphoric acid.Organic phosphates are important in biochemistry andbiogeochemistry or ecology. Inorganic phosphates aremined to obtain phosphorus for use in agriculture andindustry.[2] At elevated temperatures in the solid state,phosphates can condense to form pyrophosphates.1 Chemical propertiesR O OH POHOThis is the structural formula of the phosphoric acid functionalgroup as found in weakly acidic aqueous solution. In more basicaqueous solutions, the group donates the two hydrogen atoms andionizes as a phosphate group with a negative charge of 2.[3]The phosphate ion is a polyatomic ion with the empiricalformula PO43 and a molar mass of 94.97 g/mol. It con-sists of one central phosphorus atom surrounded by fouroxygen atoms in a tetrahedral arrangement. The phos-phate ion carries a negative-three formal charge and is theconjugate base of the hydrogen phosphate ion, HPO42,which is the conjugate base of H2PO4, the dihydrogenphosphate ion, which in turn is the conjugate base of H3PO4, phosphoric acid. A phosphate salt forms when a posi-tively charged ion attaches to the negatively charged oxy-gen atoms of the ion, forming an ionic compound. Manyphosphatesarenot solubleinwaterat standardtem-perature and pressure. The sodium, potassium, rubid-ium, caesium, and ammonium phosphates are all water-soluble. Most other phosphates are only slightly soluble orare insoluble in water. As a rule, the hydrogen and dihy-drogen phosphates are slightly more soluble than the cor-responding phosphates. The pyrophosphates are mostlywater-soluble.Aqueous phosphate exists in four forms.In strongly ba-sic conditions, the phosphate ion (PO43) predominates,whereas in weakly basic conditions, the hydrogen phos-phate ion (HPO42) is prevalent. In weakly acid condi-tions, the dihydrogen phosphate ion (H2PO4) is mostcommon. In strongly acidic conditions, trihydrogen phos-phate (H3PO4) is the main form.H3PO4Phosphoric acidH2PO4Dihydrogen phosphateHPO24Hydrogen phosphatePO34PhosphateMore precisely, considering these three equilibrium reac-tions:H3PO4 H+ + H2PO4H2PO4 H+ + HPO42HPO42 H+ + PO43the corresponding constants at 25 C (in mol/L) are (seephosphoric acid):Ka1=[H+][H2PO4][H3PO4]7.5 103(pK2.12)12 1 CHEMICAL PROPERTIESKa2=[H+][HPO24][H2PO4]6.2 108(pK7.21)Ka3=[H+][PO34][HPO24]2.14 1013(pK12.67)The speciation diagram obtained using these pK valuesshows three distinct regions. In eect, H3PO4, H2PO4 and HPO24 behave as separate weak acids. This is because thesuccessive pK values dier by more than 4. For eachacid, the pHat half-neutralization is equal to the pK valueof the acid. The region in which the acid is in equilib-rium with its conjugate base is dened by pH pK 2.Thus, the three pH regions are approximately 04, 59and 1014. This is idealized, as it assumes constant ionicstrength, which will not hold in reality at very low andvery high pH values.For a neutral pH as in the cytosol, pH=7.0[H2PO4 ][H3PO4] 7.5104,[HPO24][H2PO4 ] 0.62 ,[PO34][HPO24] 2.14106so that only H2PO4 and HPO24 ions are present in signicant amounts (62% H2PO4, 38% HPO24. Note that in the extracellular uid (pH=7.4), this pro-portion is inverted (61% HPO24, 39% H2PO4).Phosphate can formmany polymeric ions such aspyrophosphate), P2O47, and triphosphate, P3O510. The various metaphosphate ions (which are usuallylong linear polymers) have an empirical formula of PO3 and are found in many compounds.1.1 Biochemistry of phosphatesIn biological systems, phosphorus is found as a free phos-phate ion in solution and is called inorganic phosphate,to distinguish it from phosphates bound in various phos-phate esters. Inorganic phosphate is generally denoted Pand at physiological (neutral) pH primarily consists of amixture of HPO24 and H2PO4 ions.Inorganic phosphate can be created by the hydrolysis ofpyrophosphate, which is denoted PP:P2O47 + H2O 2 HPO24However, phosphates are most commonly found in theform of adenosine phosphates, (AMP, ADP, and ATP)and in DNAand RNA, and can be released by the hydrol-ysis of ATP or ADP. Similar reactions exist for the othernucleoside diphosphates and triphosphates. Phosphoan-hydride bonds in ADP and ATP,or other nucleosidediphosphates and triphosphates, contain high amounts ofenergy which give them their vital role in all living or-ganisms. They are generally referred to as high-energyphosphate, as are the phosphagens in muscle tissue. Com-pounds such as substituted phosphines have uses in or-ganic chemistry,but do not seem to have any naturalcounterparts.The addition and removal of phosphate from proteins inall cells is a pivotal strategy in the regulation of metabolicprocesses.3Referenceranges for bloodtests, showing'inorganicphosphorus in purple at right, being almost identical tothe molar concentration of phosphatePhosphate is useful in animal cells as a buering agent.Phosphatesalts that arecommonlyusedfor prepar-ing buer solutions at cell pHs include Na2HPO4,NaH2PO4, and the corresponding potassium salts.An important occurrence of phosphates in biological sys-tems is as the structural material of bone and teeth. Thesestructures are made of crystalline calcium phosphate inthe form of hydroxyapatite. The hard dense enamel ofmammalian teeth consists of uoroapatite, an hydroxycalcium phosphate where some of the hydroxyl groupshave been replaced by uoride ions.Plants take up phosphorus through several pathways: thearbuscular mycorrhizalpathway and the direct uptakepathway.2 Occurrence and miningPhosphate mine near Flaming Gorge, Utah, 2008Phosphates are the naturally occurring form of the ele-ment phosphorus, found in many phosphate minerals. Inmineralogy and geology, phosphate refers to a rock orore containing phosphate ions. Inorganic phosphates aremined to obtain phosphorus for use in agriculture andindustry.[2]Train loaded with phosphate rock, Metlaoui, Tunisia, 2012The largest phosphorite or rock phosphate deposits inNorth America lie in the Bone Valley region of cen-tral Florida, the Soda Springs region of Idaho, and thecoast of North Carolina. Smaller deposits are located inMontana, Tennessee, Georgia, and South Carolina nearCharleston along Ashley Phosphate road. The small is-land nation of Nauru and its neighbor Banaba Island,which used to have massive phosphate deposits of the bestquality, have been mined excessively. Rock phosphatecan also be found in Egypt, Israel, Morocco, Navassa Is-land, Tunisia, Togo, and Jordan, countries that have largephosphate-mining industries.Phosphorite mines are primarily found in:North America: United States, especially Florida,with lesser deposits in North Carolina, Idaho, andTennesseeAfrica: Algeria, Egypt, Morocco, mainlynearKhouribga and Youssoua;Niger, Senegal, Togo,Tunisia, and Western Sahara, at the town of Bu CraaMiddle East: Israel, Saudi Arabia, Jordan, Syria,and Iraq, at the town of Akashat, near the JordanianborderOceania: Australia, Makatea, Nauru, and BanabaIslandIn 2007, at the current rate of consumption, the supplyof phosphorus was estimated to run out in 345 years.[4]However, some scientists believed that a "peak phospho-rus" will occur in 30 years and Dana Cordell from In-stitute for Sustainable Futures said that at current rates,reserves will be depleted in the next 50 to 100 years.[5]Reserves refer to the amount assumed recoverable at cur-rent market prices, and, in 2012, the USGS estimated71 billion tons of world reserves, while 0.19 billion tonswere mined globally in 2011.[6] Phosphorus comprises0.1% by mass of the average rock[7] (while, for perspec-tive, its typical concentration in vegetation is 0.03% to0.2%),[8] and consequently there are quadrillions of tonsof phosphorus in Earths 3 * 1019ton crust,[9]albeit4 4 SEE ALSOat predominantly lower concentration than the depositscounted as reserves from being inventoried and cheaperto extract; if it is assumed that the phosphate mineralsin phosphate rock are hydroxyapatite and uoroapatite,phosphate minerals contain roughly 18,5 % phosphorusby weight and if phosphate rock contains around 20 % ofthese minerals, the average phosphate rock has roughly3,7 % phosphorus by weight.Some phosphate rock deposits are notable for their in-clusion of signicant quantities of radioactive uraniumisotopes. This syndrome is noteworthy because radioac-tivity can be released into surface waters[10] in the processof application of the resultant phosphate fertilizer (e.g. inmany tobacco farming operations in the southeast US).In December 2012, Cominco Resources announcedanupdatedJORCcompliant resourceoftheirHindaproject in Congo-Brazzaville of 531 Mt, making it thelargest measured and indicated phosphate deposit in theworld.[11]3 EcologySea surface phosphate from the World Ocean AtlasIn ecological terms, because of its important role in bi-ological systems, phosphate is a highly sought after re-source. Once used, it is often a limiting nutrient inenvironments, and its availability may govern the rate ofgrowth of organisms. This is generally true of freshwaterenvironments, whereas nitrogen is more often the limit-ing nutrient in marine (seawater) environments. Additionof high levels of phosphate to environments and to micro-environments in which it is typically rare can have signif-icant ecological consequences. For example, blooms inthe populations of some organisms at the expense of oth-ers, and the collapse of populations deprived of resourcessuch as oxygen (see eutrophication) can occur. In the con-text of pollution, phosphates are one component of totaldissolved solids, a major indicator of water quality, butnot all phosphorus is in a molecular form which algae canbreak down and consume.[12]Calcium hydroxyapatite and calcite precipitates can beRelationship of phosphate to nitrate uptake for photosynthesis invarious regions of the ocean. Note that nitrate is more often lim-iting than phosphate. See the Redeld ratio.found around bacteria in alluvial topsoil.[13] As clay min-erals promote biomineralization, the presence of bacteriaand clay minerals resulted in calcium hydroxyapatite andcalcite precipitates.[13]Phosphate deposits can contain signicant amounts ofnaturally occurring heavy metals. Mining operations pro-cessing phosphate rock can leave tailings piles contain-ingelevatedlevelsofcadmium, lead, nickel, copper,chromium, anduranium. Unlesscarefullymanaged,these waste products can leach heavy metals into ground-water or nearby estuaries. Uptake of these substances byplants and marine life can lead to concentration of toxicheavy metals in food products.[14]In Germany, the use of uranium-contaminated standardphosphate fertilizers in farming has been linked to sig-nicantly raised uranium levels in drinking water.[15] Insome areas, it has led to recommendations to use bottledwater, instead of tap water, to prepare food for babies andsmall children.4 See alsoPyrophosphate P2O74Polyphosphate PO(n+2)Metaphosphate - POnFertilizerHypophosphite H2PO2Organophosphorus compoundsPhosphate OP(OR)3, such as triphenyl phosphatePhosphate conversion coatingPhosphate soda, a soda fountain beverage5Phosphinate OP(OR)R2Phosphine PR3Phosphine oxide OPR3Phosphinite P(OR)R2Phosphite P(OR)3PhosphogypsumPhosphonate OP(OR)2RPhosphonite P(OR)2RPhosphorylationDisodium phosphate - Na2HPO4Monosodium phosphate - NaH2PO4Sodium tripolyphosphate - Na5P3O105 References[1] Phosphates PubChemPublic Chemical Database. ThePubChem Project. USA: National Center of Biotechnol-ogy Information.[2] Phosphate Primer.[3] Campbell, Neil A.; Reece, Jane B. (2005). Biology (Sev-enth ed.). San Francisco,California: Benjamin Cum-mings. p. 65. ISBN 0-8053-7171-0.[4] How Long Will it Last?". NewScientist 194 (2605):389. May 26, 2007. Bibcode:2007NewSc.194...38R.doi:10.1016/S0262-4079(07)61508-5. ISSN 0262-4079.[5] Leo Lewis (2008-06-23). Scientists warn of lack of vitalphosphorus as biofuels raise demand. The Times.[6] U.S. Geological Survey Phosphate Rock[7] U.S. Geological Survey Phosphorus Soil Samples[8] Floor Anthoni. Abundance of Elements.Seafriends.org.nz. Retrieved 2013-01-10.[9] American GeophysicalUnion, FallMeeting 2007, ab-stract #V33A-1161.Mass and Composition of the Con-tinental Crust[10] C.Michael Hogan. 2010. Water pollution.Encyclopedia of Earth. eds. MarkMcGinleyandC. Cleveland. National Council for ScienceandtheEnvironment. Washington DC.[11] Updated Hinda Resource Announcement:Now worldslargest phosphate deposit (04/12/2012)". Cominco Re-sources.[12] Hochanadel, Dave (December 10, 2010). Limitedamount of total phosphorus actually feeds algae,studynds. Lake Scientist. Retrieved June 10, 2012.[B]ioavailable phosphorus phosphorus that can be uti-lized by plants and bacteria is only a fraction of the total,according to Michael Brett, a UW engineering professor...[13] Schmittner KE, Giresse P (1999). Micro-environmentalcontrolsonbiomineralization: supercial processesofapatite and calcite precipitation in Quaternary soils,Roussillon, France. Sedimentology 46(3): 46376.doi:10.1046/j.1365-3091.1999.00224.x.[14] Gnandil, K.; Tchangbedjil, G.; Killil, K.; Babal, G.;Abbel, E. (March2006). TheImpact ofPhosphateMine Tailings on the Bioaccumulation of Heavy Metalsin Marine Fish and Crustaceans from the Coastal Zone ofTogo. Mine Water and the Environment 25 (1): 5662.doi:10.1007/s10230-006-0108-4.[15] Hintergrnde: Uran im Dnger. www.umweltinstitut.org. Retrieved 2013-01-10.6 External linksUS Minerals Databrowser provides data graphicscovering consumption, production, imports, exportsand price for phosphate and 86 other mineralsTaking Stock of Phosphorus and Biofuels,globalphosphate mining, use and shortages.Phosphate at Lab Tests OnlinePhosphate: analyte monograph - The Associationfor Clinical Biochemistry and Laboratory Medicine6 7 TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES7 Text and image sources, contributors, and licenses7.1 Text Phosphate Source:https://en.wikipedia.org/wiki/Phosphate?oldid=672281103 Contributors:AxelBoldt, Malcolm Farmer, Mark, Aldie,TomCerul, Heron, Ewen, Dwmyers, Looxix~enwiki, Ahoerstemeier, Elano, Uyanga, Ike9898, Wik, Tpbradbury, Fvw, Pollinator, Chris 73,Stewartadcock, Academic Challenger, CdaMVvWgS, Moink, GerardM, Pengo, Alan Liefting, Giftlite, Mboverload, Allstar86, Khalid has-sani, Pne, Kandar, Antandrus, Beland, Ravikiran r, MistToys, Chiu frederick, G3pro, Jossi, Rdsmith4, Kmweber, Guyincog, DanielCD,Discospinster, Vsmith, RoyBoy, West London Dweller, Adambro, Longhair, Duk, NightDragon, Nk, Haham hanuka, Alansohn, Quater-mass, Andrewpmk, Paleorthid, Plumbago, Benjah-bmm27, Howrealisreal, Walkerma, Yummifruitbat, Evil Monkey, Jheald, Henry W.Schmitt, BDD, Ceyockey, Mullet, Nuno Tavares, Mindmatrix, Madchester, GregorB, JohnJohn, EgonWillighagen, V8rik, Bsu0a7, Fre-plySpang, DePiep, BorgHunter, Rjwilmsi, PinchasC, GregAsche, Sango123, FlaBot, Margosbot~enwiki, Nihiltres, Physchim62, Bgwhite,The Rambling Man, Cuahl, YurikBot, Wavelength, Rob T Firey, RussBot, Sarranduin, Splette, Shaddack, Wimt, ENeville, Joel7687,Irishguy, MakeChooChooGoNow, Kyle Barbour, Psy guy, Private Butcher, Arthur Rubin, StealthFox, GraemeL, LeonardoRob0t, Amren,Ordinary Person, That Guy, From That Show!, DrFod, Luk, ChemGardener, Crystallina, KnightRider~enwiki, SmackBot, Saravask, Shoy,Edgar181, Mslimix, Gilliam, Hugo-cs, Chris the speller, Fuzzform, SchftyThree, Hibernian, Droll, Uthbrian, Can't sleep, clown will eatme, Julius Sahara, Solarapex, Blake-, Geor, Smokefoot, Fatal-, Drphilharmonic, DaiTengu, Ozhiker, Anlace, Kuru, John, PBarak, Breno,Cmh, IronGargoyle, Beetstra, Bendzh, Ryulong, LaMenta3, BeefontheBone, Wizard191, Iridescent, JoeBot, Tawkerbot2, Sleeping123,VoxLuna, Johner, Benzle, Ryan, Fuxya bxl, Chrislk02, Jsherwood0, Robert.Allen, ))ECB((, Epbr123, Daa89563, Ssspera, Sunjae429,Nonagonal Spider, Missvain, X201, Rfrohardt, Philippe, Natalie Erin, Mentisto, AntiVandalBot, Quintote, Antique Rose, TimVick-ers, Tillman, BeefRendang, JAnDbot, Igodard, Magioladitis, Freedomlinux, VoABot II, Jasonbrotherton, Twisted86, Quantockgoblin,Corpeter~enwiki, Ciaccona, Allstarecho, Spellmaster, DerHexer, Patstuart, Jfredrickson, NReitzel, Dbc334, Jay Litman, JTiago, Leyo,Tgeairn, J.delanoy, Trusilver, McSly, Bailo26, Mikael Hggstrm, Jayden54, DadaNeem, Smitjo, VolkovBot, Je G., AlnoktaBOT, So-liloquial, Philip Trueman, TXiKiBoT, Qxz, Shindo9Hikaru, KyleRGiggs, Melsaran, Axiosaurus, Pedvi, Yk Yk Yk, Ghetto booty, Was-sup2343, VanBuren, Jantaro, Petergans, SieBot, Mikemoral, Winchelsea, Keilana, Trang Oul, Oxymoron83, Wikidude95, Doovie, Won-derbiscuit, C'est moi, ClueBot, The Thing That Should Not Be, ImperfectlyInformed, Sigh NNNs, Lavenircestlautre, Ocer781, Excirial,Jusdafax, Capewellmj, Shinkolobwe, Wprlh, Mymj1, Muro Bot, Plasmic Physics, Ivan Akira, Rror, Andypandy2020, NellieBly, Noctibus,HexaChord, MatthewVanitas, Addbot, Wickey-nl, Nohomers48, 2corner, Quercus solaris, Rkemp, Rjm7730, Jarble, Jonathan Callahan,Luckas-bot, Ptbotgourou, CheMoBot, MauriManya, Amirobot, Yngvadottir, Tempodivalse, InterParNauru, VX, Jim1138, AdjustShift,Materialscientist, Citation bot, ArthurBot, Marshallsumter, Xqbot, Bwalke1639, , Srich32977, GrouchoBot, The rasberry,Green Cardamom, FrescoBot, HCPUNXKID, Ldkorving, Jamesooders, Georeybernardo, Nirmos, Pinethicket, Forp, 777sms, Amkil-patrick, Slippydoodle, Fema5, RjwilmsiBot, Ripchip Bot, Mburby, AchilleFouilleul, CodeXRT, Wikipelli, Dcirovic, JSquish, A930913,Tolly4bolly, Eric.archer, Snubcube, Wofuchem, DASHBotAV, Spicemix, ClueBot NG, Rbwilli, Norlns22, Rezabot, TurnspitDawg, Danim,Bibcode Bot, BG19bot, Nikos 1993, Rm1271, Driftcorn, BattyBot, Freesodas, TheJJJunk, Tyty4578, Wsydt1990, Faizan, Pranga69,Funbi, DavidLeighEllis, Arripay, Brad Dyer, Monkbot, AVeryFeynman, Trackteur, Welcome1To1The1Jungle, Kaseypeesho, Gorigoatand Anonymous: 3617.2 Images File:Blood_values_sorted_by_mass_and_molar_concentration.png Source: https://upload.wikimedia.org/wikipedia/commons/c/cb/Blood_values_sorted_by_mass_and_molar_concentration.png License: CC0 Contributors: Own work - see also References section aboveOriginal artist: Mikael Hggstrm File:Commons-logo.svg Source: https://upload.wikimedia.org/wikipedia/en/4/4a/Commons-logo.svg License: ? 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