Phosphate: Difference between revisions
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{{Short description|Anion, salt, functional group or ester derived from a phosphoric acid}}
{{About|the orthophosphate ion|the organophosphorus derivatives|Organophosphate|other phosphates|phosphoric acids and phosphates}}
{{Distinguish|phosphate soda|phosphonate|phosphorus}}
{{Chembox
| Watchedfields = changed
| verifiedrevid = 458267616
| ImageFile1 = Phosphat-Ion.svg
| ImageFile1_Ref = {{chemboximage|correct|??}}
| ImageSize1 = 140
| ImageName1 = Stereo skeletal formula of phosphate
| ImageFileL1 = Phosphate-3D-balls.png
| ImageFileL1_Ref = {{chemboximage|correct|??}}
| ImageNameL1 = Aromatic ball and stick model of phosphate
| ImageFileR1 = Phosphate-3D-vdW.png
| ImageFileR1_Ref = {{chemboximage|correct|??}}
| ImageNameR1 = Space-filling model of phosphate
| IUPACName = Phosphate<ref>{{cite web|title = Phosphates – PubChem Public Chemical Database|url = https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=1061&loc=ec_rcs|work = The PubChem Project|location = USA|publisher = National Center of Biotechnology Information}}</ref>
| OtherNames = Orthophosphate<br />Tetraoxophosphate(V)<br />Tetraoxidophosphate(V)
| Section1 = {{Chembox Identifiers
| CASNo = 14265-44-2
| CASNo_Ref = {{cascite|correct|CAS}}
|
| ChemSpiderID = 1032
|
| MeSHName = Phosphates
| ChEBI_Ref = {{ebicite|correct|EBI}}
|
| ChEMBL =
| ChEMBL_Ref =
| Beilstein = 3903772
| Gmelin = 1997
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = NK08V8K8HR
| SMILES = [O-]P([O-])([O-])=O
| SMILES_Comment = hypervalent form
|
| SMILES1_Comment = ionic form
| StdInChI = 1S/H3O4P/c1-5(2,3)4/h(H3,1,2,3,4)/p-3
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = NBIIXXVUZAFLBC-UHFFFAOYSA-K
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
| Section2 = {{Chembox Properties
|
| ConjugateAcid = [[Monohydrogen phosphate]]
|
}}
}}
In [[chemistry]], a '''phosphate''' is an [[anion]], [[salt (chemistry)|salt]], [[functional group]] or [[ester]] derived from a [[phosphoric acids and phosphates|phosphoric acid]]. It most commonly means '''orthophosphate''', a [[derivative]] of orthophosphoric acid, {{aka}} [[phosphoric acid]] {{chem2|H3PO4}}.
The '''phosphate''' or '''orthophosphate''' ion {{chem|[PO|4|]|3−}} is derived from phosphoric acid by the removal of three [[proton]]s {{chem|H|+}}. Removal of one proton gives the '''dihydrogen phosphate''' ion {{chem|[H|2|PO|4|]|−}} while removal of two protons gives the '''hydrogen phosphate''' ion {{chem|[HPO|4|]|2−}}. These names are also used for salts of those anions, such as [[ammonium dihydrogen phosphate]] and [[trisodium phosphate]].
<gallery heights="110" mode="packed">
File:3-phosphoric-acid-3D-balls.png|{{chem|H|3|PO|4}}<br />[[Phosphoric acid|Phosphoric<br />acid]]
File:2-dihydrogenphosphate-3D-balls.png|{{chem|[H|2|PO|4|]|-}}<br />[[Dihydrogen phosphate|Dihydrogen<br />phosphate]]
File:1-hydrogenphosphate-3D-balls.png|{{chem|[HPO|4|]|2−}}<br />[[Monohydrogen phosphate|Hydrogen<br />phosphate]]
File:0-phosphate-3D-balls.png|{{chem|[PO|4|]|3−}}<br />'''Phosphate''' or '''orthophosphate'''
</gallery>
In [[organic chemistry]], '''phosphate''' or '''orthophosphate''' is an [[organophosphate]], an ester of orthophosphoric acid of the form {{chem|PO|4|RR′R″}} where one or more hydrogen atoms are replaced by [[organic compound|organic]] groups. An example is [[trimethyl phosphate]], {{chem|(CH|3|)|3|PO|4}}. The term also refers to the [[valence (chemistry)|trivalent]] functional group {{chem|OP|(O-)|3}} in such esters. Phosphates may contain sulfur in place of one or more oxygen atoms ([[thiophosphate]]s and [[organothiophosphate]]s).
Orthophosphates are especially important among the various [[phosphoric acids and phosphates|phosphates]] because of their key roles in [[biochemistry]], [[biogeochemistry]], and [[ecology]], and their economic importance for [[agriculture]] and industry.<ref name=PhosphatePrimer>{{cite web |url=http://www.fipr.state.fl.us/about-us/phosphate-primer/ |title=Phosphate Primer |url-status=live |archive-url=https://web.archive.org/web/20170829055956/http://www.fipr.state.fl.us/about-us/phosphate-primer/ |archive-date=29 August 2017 |website=Florida Industrial and Phosphate Research Institute |publisher=Florida Polytechnic University |access-date=30 March 2018 }}</ref> The addition and removal of phosphate groups ([[phosphorylation]] and [[dephosphorylation]]) are key steps in [[cell (biology)|cell]] [[metabolism]].
[[Orthophosphate|Orthophosphates]] can [[Condensation reaction|condense]] to form [[pyrophosphate]]s.
==Chemical properties==
The phosphate ion has a [[molar mass]] of 94.97 g/mol, and consists of a central [[phosphorus]] atom surrounded by four [[oxygen]] atoms in a [[tetrahedron|tetrahedral]] arrangement. It is the [[conjugate acid|conjugate base]] of the hydrogen phosphate ion {{chem|H(PO|4|)|2−}}, which in turn is the conjugate base of the dihydrogen phosphate ion {{chem|H|2|(PO|4|)|−}}, which in turn is the conjugate base of [[phosphoric acid|orthophosphoric acid]], {{chem|H|3|PO|4}}.
===Equilibria in solution===
[[File:PiSpeciation.svg|alt=|thumb|265x265px|Phosphoric acid [[Ion speciation|speciation]]]]
In water solution, orthophosphoric acid and its three derived anions coexist according to the dissociation and recombination equilibria below<ref>{{cite book|last = Campbell|first = Neil A.|author-link = Neil Campbell (scientist)|author2=Reece, Jane B.|title = Biology|edition = Seventh|publisher = [[Benjamin Cummings]]|year = 2005|location = San Francisco, California|page = 65|isbn = 0-8053-7171-0 }}</ref>
{| class="wikitable"
! Equilibrium
! Dissociation constant ''K''<sub>a</sub><ref name=pow2005/>
! p''K''<sub>''a''</sub>
|-
| {{chem2|H<sub>3</sub>PO<sub>4</sub> <-> H2PO4- + H+}}
| <math chem>K_{a1} = \frac{[\ce{H+}][\ce{H2PO4-}]}{[\ce{H3PO4}]} \approx 7.5 \times 10^{-3}</math>
| p''K''<sub>a1</sub> = 2.14
|-
| {{chem2|H2PO4- <-> HPO4(2-) + H+}}
| <math chem>K_{a2} = \frac{[\ce{H+}][\ce{HPO4^2-}]}{[\ce{H2PO4-}]} \approx 6.2 \times 10^{-8}</math>
| p''K''<sub>a2</sub> = 7.20
|-
| {{chem2|HPO4(2-) <-> PO4(3-) + H+}}
| <math chem>K_{a3} = \frac{[\ce{H+}][\ce{PO4^3-}]}{[\ce{HPO4^2-}]} \approx 2.14 \times 10^{-13}</math>
| p''K''<sub>a3</sub> = 12.37
|}
Values are at 25{{nbsp}}°C and 0 ionic strength.
The p''K''<sub>''a''</sub> values are the [[pH]] values where the concentration of each species is equal to that of its [[conjugate base]]s. At pH 1 or lower, the phosphoric acid is practically undissociated. Around pH 4.7 (mid-way between the first two p''K''<sub>''a''</sub> values) the dihydrogen phosphate ion, {{chem|[H|2|PO|4|]|−}}, is practically the only species present. Around pH 9.8 (mid-way between the second and third p''K''<sub>''a''</sub> values) the monohydrogen phosphate ion, {{chem|[H||PO|4|]|2−}}, is the only species present. At pH 13 or higher, the acid is completely dissociated as the phosphate ion, {{chem|(PO|4|)|3−}}.
This means that salts of the mono- and di-phosphate ions can be selectively crystallised from aqueous solution by setting the pH value to either 4.7 or 9.8.
In effect, {{chem|H|3|PO|4}}, {{chem|H|2|(PO|4|)|−}} and {{chem|H(PO|4|)|2−}} behave as separate [[weak acid]]s because the successive p''K''<sub>''a''</sub> differ by more than 4.
Phosphate can form many [[polymer]]ic ions such as [[pyrophosphate]], {{chem|(P|2|O|7|)|4-}}, and [[Sodium triphosphate|triphosphate]], {{chem|(P|3|O|10|)|5-}}. The various [[metaphosphate]] ions (which are usually long linear polymers) have an empirical formula of {{chem|(PO|3|)|−}} and are found in many compounds.
===Biochemistry of phosphates===
<!-- This heading is an anchor linked from other articles -->
In [[biological system]]s, phosphorus can be found as free phosphate anions in solution ('''inorganic phosphate''') or bound to organic molecules as various [[organophosphate]]s.
Inorganic phosphate is generally denoted '''P<sub>i</sub>''' and at physiological ([[Homeostasis|homeostatic]]) [[pH]] primarily consists of a mixture of {{chem|[HPO|4|]|2−}} and {{chem|[H|2|PO|4|]|−}} ions. At a neutral pH, as in the [[cytosol]] (pH = 7.0), the concentrations of the orthophoshoric acid and its three anions have the ratios
<math chem display=block>\begin{align}
\frac{[\ce{H2PO4-}]}{[\ce{H3PO4}]} &\approx 7.5 \times 10^4 \\[4pt]
\frac{[\ce{HPO4^2-}]}{[\ce{H2PO4-}]} &\approx 0.62 \\[4pt]
\frac{[\ce{PO4^3-}]}{[\ce{HPO4^2-}]} &\approx 2.14 \times 10^{-6}
\end{align}</math>
Thus, only {{chem|[H|2|PO|4|]|−}} and {{chem|[HPO|4|]|2−}} ions are present in significant amounts in the cytosol (62% {{chem|[H|2|PO|4|]|−}}, 38% {{chem|[HPO|4|]|2−}}). In extracellular fluid (pH = 7.4), this proportion is inverted (61% {{chem|[HPO|4|]|2−}}, 39% {{chem|[H|2|PO|4|]|−}}).
Inorganic phosphate can also be present as [[pyrophosphate]] anions {{chem|[P|2|O|7|]|4-}}, which give orthophosphate by [[hydrolysis]]:
:{{chem|[P|2|O|7|]|4-}} + H<sub>2</sub>O {{eqm}} 2 {{chem|[HPO|4|]|2−}}
Organic phosphates are commonly found in the form of esters as [[nucleotide]]s (e.g. [[Adenosine monophosphate|AMP]], [[Adenosine diphosphate|ADP]], and [[Adenosine triphosphate|ATP]]) and in [[DNA]] and [[RNA]]. Free orthophosphate anions can be released by the hydrolysis of the [[phosphoanhydride]] bonds in ATP or ADP. These [[phosphorylation]] and [[dephosphorylation]] reactions are the immediate storage and source of energy for many [[metabolism|metabolic]] processes. ATP and ADP are often referred to as [[high-energy phosphate]]s, as are the [[phosphagen]]s in muscle tissue. Similar reactions exist for the other nucleoside [[nucleoside diphosphate|diphosphates]] and [[nucleoside triphosphate|triphosphates]].
===Bones and teeth===
An important occurrence of phosphates in biological systems is as the structural material of bone and teeth. These structures are made of crystalline [[calcium phosphate]] in the form of [[hydroxylapatite|hydroxyapatite]]. The hard dense enamel of [[mammalian teeth]] may contain [[fluoroapatite]], a [[hydroxyl|hydroxy]] calcium phosphate where some of the [[hydroxyl]] groups have been replaced by [[fluoride]] ions.
===Medical and biological research uses===
Phosphates are medicinal salts of phosphorus. Some phosphates, which help cure many [[urinary tract infection]]s, are used to make urine more acidic. To avoid the development of [[calcium stone]]s in the urinary tract, some phosphates are used.<ref name=":0">{{Cite web|title=Phosphate Supplement (Oral Route, Parenteral Route) Description and Brand Names - Mayo Clinic|url=https://www.mayoclinic.org/drugs-supplements/phosphate-supplement-oral-route-parenteral-route/description/drg-20070193|access-date=2020-11-20|website=www.mayoclinic.org}}</ref> For patients who are unable to get enough phosphorus in their daily diet, phosphates are used as dietary supplements, usually because of certain disorders or diseases.<ref name=":0" /> Injectable phosphates can only be handled by qualified health care providers.<ref name=":0" />
===Plant metabolism===
Plants take up phosphorus through several pathways: the [[arbuscular mycorrhizal]] pathway and the direct uptake pathway.
== Adverse health effects ==
{{More citations needed|date=July 2022}}
[[Hyperphosphatemia]], or a high blood level of phosphates, is associated with elevated [[Mortality rate|mortality]] in the general population. The most common cause of hyperphosphatemia in people, dogs, and cats is kidney failure. In cases of hyperphosphatemia, limiting consumption of phosphate-rich foods, such as some meats and dairy items and foods with a high phosphate-to-protein ratio, such as soft drinks, fast food, processed foods, condiments, and other products containing phosphate-salt additives is advised.<ref>Renal Dietitian Team, ''[https://www.ouh.nhs.uk/patient-guide/leaflets/files/56112Pphosphate.pdf Reducing phosphate in your diet]'', Oxford University Hospitals NHS Foundation Trust, 2022 review </ref>
Phosphates induce vascular [[calcification]], and a high concentration of phosphates in blood was found to be a predictor of [[Cardiovascular disease|cardiovascular events]].<ref name=":1">{{Cite journal|last1=Ritz|first1=Eberhard|last2=Hahn|first2=Kai|last3=Ketteler|first3=Markus|last4=Kuhlmann|first4=Martin K.|last5=Mann|first5=Johannes|date=January 2012|title=Phosphate additives in food--a health risk|journal=Deutsches Ärzteblatt International|volume=109|issue=4|pages=49–55|doi=10.3238/arztebl.2012.0049|issn=1866-0452|pmc=3278747|pmid=22334826}}</ref>
==Production==
===Geological occurrence===
[[File:Phosphate Mine Panorama.jpg|thumb|upright=1.7|Phosphate mine near [[Flaming Gorge, Utah]], US, 2008]]
[[File:Train loaded with phosphate rock, Metlaoui Tunisia-4298B.jpg|thumb|Train loaded with phosphate rock, [[Métlaoui]], Tunisia, 2012]]
Phosphates are the naturally occurring form of the element [[phosphorus]], found in many [[phosphate mineral]]s. In mineralogy and geology, phosphate refers to a rock or ore containing phosphate ions. Inorganic phosphates are [[mining|mined]] to obtain phosphorus for use in agriculture and industry.<ref name=PhosphatePrimer/>
The largest global producer and exporter of phosphates is [[Morocco]]. Within North America, the largest deposits lie in the [[Bone Valley]] region of central [[Florida]], the [[Soda Springs, Idaho|Soda Springs]] region of southeastern [[Idaho]], and the coast of [[North Carolina]]. Smaller deposits are located in [[Montana]], [[Tennessee]], [[Georgia (U.S. state)|Georgia]], and [[South Carolina]]. The small island nation of [[Phosphate mining in Nauru|Nauru]] and its neighbor [[Banaba Island]], which used to have massive phosphate deposits of the best quality, have been mined excessively. Rock phosphate can also be found in Egypt, Israel, Palestine, Western Sahara, [[Navassa Island]], Tunisia, Togo, and Jordan, countries that have large phosphate-mining industries.
[[Phosphorite]] mines are primarily found in:
* '''North America''': {{main|Phosphate mining in the United States}} United States, especially Florida, with lesser deposits in [[North Carolina]], [[Idaho]], and [[Tennessee]]
* '''Africa''': [[Morocco]], [[Algeria]], [[Egypt]], [[Niger]], [[Senegal]], [[Togo]], [[Tunisia]], [[Mauritania]]
* '''Middle East''': [[Saudi Arabia]], [[Jordan]], [[Israel]], [[Syria]], [[Iran]] and [[Iraq]], at the town of [[Akashat]], near the Jordanian border.
* '''Central Asia''': [[Kazakhstan]]
* '''Oceania''': [[Australia]], [[Makatea]], [[Nauru]], and [[Banaba Island]]
In 2007, at the current rate of consumption, the supply of phosphorus was estimated to run out in 345 years.<ref>{{cite journal|date=May 26, 2007|journal = [[New Scientist]]|volume = 194|issue = 2605|pages = 38–9|title = How Long Will it Last?|doi=10.1016/S0262-4079(07)61508-5|bibcode = 2007NewSc.194...38R |last1 = Reilly|first1 = Michael}}</ref> However, some scientists thought that a "[[peak phosphorus]]" would occur in 30 years and [[Dana Cordell]] from Institute for Sustainable Futures said <!-- in Times --> that at "current rates, reserves will be depleted in the next 50 to 100 years".<ref name=Lewis>{{cite news|url = http://business.timesonline.co.uk/tol/business/industry_sectors/natural_resources/article4193017.ece|title = Scientists warn of lack of vital phosphorus as biofuels raise demand|date = 2008-06-23|author = Leo Lewis|newspaper = The Times}}</ref> Reserves refer to the amount assumed recoverable at current market prices. In 2012 the [[United States Geological Survey|USGS]] estimated world reserves at 71 billion tons, while 0.19 billion tons were mined globally in 2011.<ref>U.S. Geological Survey [http://minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/mcs-2012-phosp.pdf Phosphate Rock]</ref> Phosphorus comprises 0.1% by mass of the average rock<ref>[[U.S. Geological Survey]] {{cite web| url = http://pubs.usgs.gov/of/2004/1368/Soil_PDFs/P_soils_page.pdf| title = Phosphorus Soil Samples}}</ref> (while, for perspective, its typical concentration in vegetation is 0.03% to 0.2%),<ref>{{cite web|author=Floor Anthoni |url=http://www.seafriends.org.nz/oceano/abund.htm |title=Abundance of Elements |publisher=Seafriends.org.nz |access-date=2013-01-10}}</ref> and consequently there are quadrillions of tons of phosphorus in Earth's 3×10<sup>19</sup>-ton crust,<ref>[[American Geophysical Union]], Fall Meeting 2007, abstract #V33A-1161. [http://adsabs.harvard.edu/abs/2007AGUFM.V33A1161P Mass and Composition of the Continental Crust]</ref> albeit at predominantly lower concentration than the deposits counted as reserves, which are inventoried and cheaper to extract. If it is assumed that the phosphate minerals in [[phosphate rock]] are mainly hydroxyapatite and fluoroapatite, phosphate minerals contain roughly 18.5% phosphorus by weight. If phosphate rock contains around 20% of these minerals, the average phosphate rock has roughly 3.7% phosphorus by weight.
Some phosphate rock deposits, such as [[Mulberry, Florida#Economy|Mulberry]] in Florida,<ref name="Mulberry, Phosphate" /> are notable for their inclusion of significant quantities of radioactive uranium isotopes. This is a concern because radioactivity can be released into surface waters<ref>{{cite encyclopedia |author=C. Michael Hogan |year=2010 |url=http://www.eoearth.org/article/Water_pollution |title=Water pollution |encyclopedia=[[Encyclopedia of Earth]] |editor=Mark McGinley and C. Cleveland (Washington, DC.: [[National Council for Science and the Environment]]) |archive-url=https://web.archive.org/web/20100916050147/http://www.eoearth.org/article/Water_pollution |archive-date=2010-09-16}}</ref> from application of the resulting [[Fertilizer#Phosphate fertilizers|phosphate fertilizer]].
In December 2012, [[Cominco Resources]] announced an updated [[JORC]] compliant resource of their Hinda project in [[Republic of the Congo|Congo-Brazzaville]] of 531 million tons, making it the largest measured and indicated phosphate deposit in the world.<ref>{{cite web|title=Updated Hinda Resource Announcement: Now world's largest phosphate deposit (04/12/2012)|url=http://www.comincoresources.com/news/updated-hinda-resource-announcement-now-worlds-largest-phosphate-deposit-04|publisher=[[Cominco Resources]]|access-date=2013-05-03|archive-url=https://web.archive.org/web/20161005113748/http://www.comincoresources.com/news/updated-hinda-resource-announcement-now-worlds-largest-phosphate-deposit-04|archive-date=2016-10-05|url-status=dead}}</ref>
Around 2018, Norway discovered phosphate deposits almost equal to those in the rest of Earth combined.<ref>{{cite news |url=https://www.dw.com/en/eu-pins-hope-on-norway-raw-materials-discovery/a-56343829 |title=EU pins hope on Norway's raw materials |last1=Bushuev |first1=Mikhail |date=26 January 2021 |accessdate=2 July 2023}}</ref><ref>https://www.euractiv.com/section/energy-environment/news/great-news-eu-hails-discovery-of-massive-phosphate-rock-deposit-in-norway/</ref>
In July 2022 China announced quotas on phosphate exportation.<ref>{{cite news | url=https://www.reuters.com/article/china-fertilizers-quotas/china-issues-phosphate-quotas-to-rein-in-fertiliser-exports-analysts-idUSKBN2OQ0KY | title=China issues phosphate quotas to rein in fertiliser exports - analysts | newspaper=Reuters | date=15 July 2022 }}</ref>
The largest importers in millions of metric tons of phosphate are Brazil 3.2, India 2.9 and the USA 1.6.<ref>{{cite web | url=https://www.nationmaster.com/nmx/ranking/phosphate-fertilizer-imports | title=Top countries for Phosphate Fertilizer Imports }}</ref>
===Mining===
[[File:International Exchange of Phosphates in 1937 - DPLA - 03790fc57d3206e73683a68ec11c8fb2.jpg|thumb|right|Phosphate imports/exports in 1937]]
The three principal phosphate producer countries (China, Morocco and the United States) account for about 70% of world production.
{| class="wikitable centre sortable width=80%;"
|+ Production and global reserves of natural phosphate by country in 2019<br /><small>(USGS, 2021)</small><ref>{{cite web| url = https://pubs.usgs.gov/periodicals/mcs2021/mcs2021-phosphate.pdf| title = PHOSPHATE ROCK, usgs}}</ref>
! Country !! Production <br />(millions kg) !! Share of <br /> global <br /> production (%) !! Reserves<br />(millions kg)
|-
| [[Algeria]] || align="right" | {{formatnum:1300}} || align="right" | 0.54 || align="right" | {{formatnum:2200000}}
|-
| [[Australia]] || align="right" | {{formatnum:2700}} || align="right" | 1.17 || align="right" | {{formatnum:1100000}}
|-
| [[Brazil]] || align="right" | {{formatnum:4700}} || align="right" | 3.00 || align="right" | {{formatnum:1600000}}
|-
| [[China]] || align="right" | {{formatnum:95000}} || align="right" | 44.83 || align="right" | {{formatnum:3200000}}
|-
| [[Egypt]] || align="right" | {{formatnum:5000}} || align="right" | 2.47 || align="right" | {{formatnum:2800000}}
|-
|[[Finland]] || align="right" | {{formatnum:995}} || align="right" | - || align="right" | {{formatnum:1000000}}
|-
| [[India]] || align="right" | {{formatnum:1,480}} || align="right" | 0.49 || align="right" | {{formatnum:46000}}
|-
| [[Iraq]] || align="right" | {{formatnum:200}} || align="right" | 0.09 || align="right" | {{formatnum:430000}}
|-
| [[Israel]] || align="right" | {{formatnum:2,810}} || align="right" | 1.48 || align="right" | {{formatnum:57000}}
|-
| [[Jordan]] || align="right" | {{formatnum:9,220}} || align="right" | 3.36 || align="right" | {{formatnum:800000}}
|-
| [[Kazakhstan]] || align="right" | {{formatnum:1500}} || align="right" | 0.72 || align="right" | {{formatnum:260000}}
|-
| [[Mexico]] || align="right" | {{formatnum:558}} || align="right" | 0.76 || align="right" | {{formatnum:30000}}
|-
| [[Morocco]] and [[Western Sahara]] || align="right" |{{formatnum:35500}} || align="right" | 13.45 || align="right" | {{formatnum:50000000}}
|-
| [[Peru]] || align="right" | {{formatnum:4000}} || align="right" | 1.79 || align="right" | {{formatnum:210000}}
|-
| [[Russia]] || align="right" | {{formatnum:13100}} || align="right" | 5.60 || align="right" | {{formatnum:600000}}
|-
| [[Saudi Arabia]] || align="right" | {{formatnum:6500}} || align="right" | 1.48 || align="right" | {{formatnum:1400000}}
|-
| [[Senegal]] || align="right" | {{formatnum:3,420}} || align="right" | 0.45 || align="right" | {{formatnum:50000}}
|-
| [[South Africa]] || align="right" | {{formatnum:2100}} || align="right" | 0.99 || align="right" | {{formatnum:1400000}}
|-
| [[Syria]] || align="right" | {{formatnum:2000}} || align="right" | 0.34 || align="right" | {{formatnum:1800000}}
|-
| [[Togo]] || align="right" | {{formatnum:800}} || align="right" | 0.45 || align="right" | {{formatnum:30000}}
|-
| [[Tunisia]] || align="right" | {{formatnum:4,110}} || align="right" | 1.79 || align="right" | {{formatnum:100000}}
|-
|[[Uzbekistan]] || align="right" | {{formatnum:900}} || align="right" | - || align="right" | {{formatnum:100000}}
|-
| [[United States]] || align="right" | {{formatnum:23300}} || align="right" | 12.37 || align="right" | {{formatnum:1000000}}
|-
| [[Vietnam]] || align="right" | {{formatnum:4,650}} || align="right" | 1.21 || align="right" | {{formatnum:30000}}
|-class="sortbottom"
| Other countries || align="right" | {{formatnum:1,140}} || align="right" | 1.17 || align="right" | {{formatnum:840000}}
|-class="sortbottom" style="background: #EFEFEF"
| '''Total''' || align="right" | '''{{formatnum:227000}}''' || align="right" | '''100''' || align="right" | '''{{formatnum:71000000}}'''
|}
== Ecology ==<!-- Other articles link here -->
[[File:WOA09 sea-surf PO4 AYool.png|left|thumb|Sea surface phosphate from the [[World Ocean Atlas]]]]
[[File:PhosphatetoNitrate.png|thumb|upright=1.25|Relationship of phosphate to nitrate uptake for [[photosynthesis]] in various regions of the ocean. Note that nitrate is more often limiting than phosphate. See the [[Redfield ratio]].]]
In ecological terms, because of its important role in biological systems, phosphate is a highly sought after resource. Once used, it is often a limiting nutrient in [[Environment (biophysical)|environments]], and its availability may govern the rate of growth of organisms. This is generally true of [[freshwater]] environments, whereas nitrogen is more often the limiting nutrient in marine (seawater) environments. Addition of high levels of phosphate to environments and to micro-environments in which it is typically rare can have significant ecological consequences. For example, blooms in the populations of some organisms at the expense of others, and the collapse of populations deprived of resources such as oxygen (see [[eutrophication]]) can occur. In the context of pollution, phosphates are one component of [[total dissolved solids]], a major indicator of water quality, but not all phosphorus is in a molecular form that algae can break down and consume.<ref>{{cite web|last=Hochanadel|first=Dave|title=Limited amount of total phosphorus actually feeds algae, study finds|url=http://www.lakescientist.com/2010/limited-amount-of-total-phosphorus-actually-feeds-algae-study-finds|publisher=Lake Scientist|access-date=June 10, 2012|date=December 10, 2010|quote=[B]ioavailable phosphorus – phosphorus that can be utilized by plants and bacteria – is only a fraction of the total, according to Michael Brett, a UW engineering professor ...}}</ref>
Calcium hydroxyapatite and calcite precipitates can be found around [[bacteria]] in [[alluvial]] topsoil.<ref name=Schmittner>{{cite journal |author=Schmittner KE, Giresse P |title=Micro-environmental controls on biomineralization: superficial processes of apatite and calcite precipitation in Quaternary soils, Roussillon, France |journal=Sedimentology |volume=46 |issue=3 |year=1999 |pages=463–76 |doi=10.1046/j.1365-3091.1999.00224.x|bibcode=1999Sedim..46..463S |s2cid=140680495 }}</ref> As clay minerals promote biomineralization, the presence of bacteria and clay minerals resulted in calcium hydroxyapatite and calcite precipitates.<ref name=Schmittner/>
Phosphate deposits can contain significant amounts of naturally occurring heavy metals. Mining operations processing [[phosphate rock]] can leave [[tailings]] piles containing elevated levels of [[cadmium]], [[lead]], [[nickel]], [[copper]], [[chromium]], and [[uranium]]. Unless carefully managed, these waste products can leach heavy metals into groundwater or nearby estuaries. Uptake of these substances by plants and marine life can lead to concentration of toxic heavy metals in food products.<ref>{{cite journal|last1 =
==See also==
{{div col|colwidth=20em}}
* [[Diammonium phosphate]] - (NH<sub>4</sub>)<sub>2</sub>HPO<sub>4</sub>
* [[Disodium phosphate]] – Na<sub>2</sub>HPO<sub>4</sub>
* [[Fertilizer]]
* [[Hypophosphite]] – {{chem|H|2|(PO|2|)|−}}
* [[Metaphosphate]] – {{chem|(P|O|3|)|''n''}}
* [[
* [[Organophosphorus]] compounds
* [[Ouled Abdoun Basin]]
*
* [[Phosphate conversion coating]]
* [[Phosphate soda]], a soda fountain beverage
* [[
* [[Phosphine]] – PR<sub>3</sub>
* [[
* [[Phosphinite]] – P(OR)R<sub>2</sub>
* [[
* [[Phosphogypsum]]
* [[Phosphonate]] – OP(OR)<sub>2</sub>R
* [[Phosphonite]] – P(OR)<sub>2</sub>R
* [[
* [[Polyphosphate]] – {{chem|(H|P|O|3|)|''n''}}
* [[Pyrophosphate]] – {{chem|(P|2|O|7|)|4−}}
* [[Sodium tripolyphosphate]] – Na<sub>5</sub>P<sub>3</sub>O<sub>10</sub>
{{div col end}}
==References==
{{Reflist|refs=
<ref name=pow2005>Kipton J. Powell, Paul L. Brown, Robert H. Byrne, Tamás Gajda, Glenn Hefter, Staffan Sjöberg, Hans Wanner (2005): "Chemical speciation of environmentally significant heavy metals with inorganic ligands. Part 1: The {{chem|Hg|2+}}, Cl<sup>−</sup>, OH<sup>−</sup>, {{chem|CO|3|2−}}, {{chem|SO|4|2−}}, and {{chem|PO|4|3−}} aqueous systems". ''Pure and Applied Chemistry'', volume 77, issue 4, pages 739–800. {{doi|10.1351/pac200577040739}}</ref>
<ref name="Mulberry, Phosphate" >{{Cite book
|title=Central Florida Phosphate Industry: Environmental Impact Statement
|volume=2
|publisher=United States. Environmental Protection Agency
|year=1979
|url=https://books.google.com/books?id=Q_g0AQAAMAAJ&pg=SA2-PA26
}}</ref>
}}
==External links==
{{Commons category|Phosphates}}
* [https://web.archive.org/web/20110311113613/http://mazamascience.com/Minerals/USGS/ US Minerals Databrowser] provides data graphics covering consumption, production, imports, exports and price for phosphate and 86 other minerals
* [https://web.archive.org/web/20121113144350/http://www.acb.org.uk/docs/NHLM/Phosphate.pdf Phosphate: analyte monograph] – The Association for Clinical Biochemistry and Laboratory Medicine
{{Phosphates}}
{{Phosphate minerals}}
{{Authority control}}
[[Category:Functional groups]]
[[Category:
[[Category:Phosphates| ]]
[[Category:Industrial minerals]]
[[Category:Concrete admixtures]]
[[Category:Phosphorus(V) compounds]]
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