Editing Sodium phosphate

{{Short description|Sodium salts of phosphoric acid}}
{{about||the chemical known as sodium phosphate|Trisodium phosphate}}
[[File:monosodium phosphate.png|thumb|right|150px|[[Sodium dihydrogen phosphate]]]]
[[File:disodium hydrogen phosphate.png|thumb|150px|right|[[Sodium hydrogen phosphate]]]]
[[File:trisodium phosphate.png|thumb|right|150px|[[Trisodium phosphate]]]]

A '''sodium phosphate''' is a generic variety of [[salt (chemistry)|salt]]s of [[sodium]] ({{chem2|Na+}}) and [[phosphate]] ({{chem2|PO4(3−)}}). Phosphate also forms families or condensed [[anion]]s including di-, tri-, tetra-, and [[polyphosphate]]s. Most of these salts are known in both [[anhydrous]] (water-free) and [[hydrated]] forms. The hydrates are more common than the anhydrous forms.<ref name=Ullmann>{{Ullmann|author1=Klaus Schrödter|author2=Gerhard Bettermann|author3=Thomas Staffel|author4=Friedrich Wahl|author5=Thomas Klein|author6=Thomas Hofmann|title=Phosphoric Acid and Phosphates|doi=10.1002/14356007.a19_465.pub3|year=2012}}</ref>

==Uses==
Sodium phosphates have many applications in food and for water treatment. For example, sodium phosphates are often used as [[emulsifier]]s (as in [[processed cheese]]),<ref>{{cite web |url=http://www.sodiumphosphateformula.com/tag/monosodium-phosphate |url-status=dead |archive-url=https://web.archive.org/web/20150402120338/http://www.sodiumphosphateformula.com/tag/monosodium-phosphate |archive-date=2015-04-02 |title=Monosodium Phosphate {{!}} Sodium Phosphate Formula}}</ref> [[thickening agent]]s, and [[leavening agent]]s for baked goods. They are also used to control pH of processed foods.<ref>{{cite journal | last1 = Lampila | first1 = Lucina E. | year = 2013 | title = Applications and functions of food-grade phosphates | journal =  Annals of the New York Academy of Sciences| volume = 1301 | issue = 1| pages = 37–44 | doi = 10.1111/nyas.12230 | pmid = 24033359 | bibcode = 2013NYASA1301...37L | s2cid = 206223856 | doi-access = free}}</ref> They are also used in medicine for [[constipation]] and to prepare the bowel for medical procedures. They are also used in detergents for softening water and as an efficient anti-[[rust]] solution.

==Adverse effects==
Sodium phosphates are popular in commerce in part because they are inexpensive and because they are nontoxic at normal levels of consumption.<ref>{{cite journal | pmc = 3120105| year = 2011| last1 = Razzaque| first1 = M. S.| title = Phosphate toxicity: New insights into an old problem| journal = Clinical Science| volume = 120| issue = 3| pages = 91–97| doi = 10.1042/CS20100377| pmid=20958267}}</ref> However, oral sodium phosphates when taken at high doses for [[bowel preparation]] for [[colonoscopy]] may in some individuals carry a risk of kidney injury under the form of [[phosphate nephropathy]]. There are several oral phosphate formulations which are prepared extemporaneously. Oral phosphate prep drugs have been withdrawn in the United States, although evidence of causality is equivocal.<ref>{{cite journal |last1= Markawitz |first1= GB |last2= Parezelli |first2= MA |date= Aug 12, 2007 |title= Acute Phosphate Nephropathyl |journal=Kidney International |volume= 76 |issue= 10 |pages= 1027–34 |doi= 10.1038/ki.2009.308 |pmid= 19675530 |doi-access= free }}</ref> Since safe and effective replacements for phosphate purgatives are available, several medical authorities have recommended general disuse of oral phosphates.<ref>{{Cite journal |last1= Mackey |first1= AC |last2= Breen |first2= L |last3= Amand |first3= KS |last4= Evigan |first4= M |date= August 2007 |title= Sodium phosphate tablets and acute Phosphate Nephropathy |journal= The American Journal of Gastroenterology|volume=104 |issue=8 |pages=1903–1906 |doi= 10.1038/ajg.2009.342 |pmid= 19661931 |s2cid= 12551005 |url= https://zenodo.org/record/1233245}}</ref>

==Monophosphates==
Three families of sodium monophosphates are common, those derived from orthophosphate ({{chem2|PO4(3−)}}), hydrogen phosphate ({{chem2|HPO4(2−)}}), and dihydrogenphosphate ({{chem2|H2PO4−}}). Some of the best known salts are shown in the following table.

{|class="wikitable"
|-
! name
! formula
! [[CAS registry number]]
|-
| [[monosodium phosphate]] (anhydrous) || {{chem2|NaH2PO4}}||7558-80-7
|-
| monosodium phosphate monohydrate|| {{chem2|NaH2PO4*H2O}}||10049-21-5
|-
| monosodium phosphate dihydrate|| {{chem2|NaH2PO4*2H2O}}||13472-35-0
|-
| [[disodium phosphate]] (anhydrous) || {{chem2|Na2HPO4}} || 7558–79–4
|-
| disodium phosphate dihydrate|| {{chem2|Na2HPO4*2H2O}}||10028-24-7
|-
| disodium phosphate heptahydrate|| {{chem2|Na2HPO4*7H2O}} || 7782–85–6
|-
| disodium phosphate octahydrate|| {{chem2|Na2HPO4*8H2O}}||
|-
| disodium phosphate dodecahydrate|| {{chem2|Na2HPO4*12H2O}} || 10039–32–4
|-
| [[trisodium phosphate]] (anhydrous, hexagonal) || {{chem2|Na3PO4}}||
|-
| trisodium phosphate (anhydrous, cubic) || {{chem2|Na3PO4}} || 7601–54–9
|-
| trisodium phosphate hemihydrate|| {{chem2|Na3PO4*0.5H2O}}||
|-
| trisodium phosphate hexahydrate|| {{chem2|Na3PO4*6H2O}} ||
|-
| trisodium phosphate octahydrate|| {{chem2|Na3PO4*8H2O}}||
|-
| trisodium phosphate dodecahydrate|| {{chem2|Na3PO4*12H2O}}||10101-89-0
|-
|}

==Di- and polyphosphates==
In addition to these phosphates, sodium forms a number of useful salts with [[pyrophosphate]]s (also called diphosphates), triphosphates and high polymers. Of these salts, those of the diphosphates are particularly common commercially.
{|class="wikitable"
|-
! name
! formula
! CAS Registry number
|-
| [[monosodium diphosphate]] (anhydrous) || {{chem2|NaH3P2O7}}||
|-
| [[disodium diphosphate]] (anhydrous) || {{chem2|Na2H2P2O7}}||7758-16-9
|-
| disodium diphosphate hexahydrate|| {{chem2|Na2H2P2O7*6H2O}}||
|-
| [[trisodium diphosphate]] (anhydrous) || {{chem2|Na3HP2O7}}||
|-
| trisodium diphosphate monohydrate|| {{chem2|Na3HP2O7*H2O}}||
|-
| trisodium diphosphate nonahydrate|| {{chem2|Na3HP2O7*9H2O}}||
|-
| [[tetrasodium diphosphate]] (anhydrous) || {{chem2|Na4P2O7}}||7722-88-5
|-
| tetrasodium diphosphate decahydrate|| {{chem2|Na4P2O7*10H2O}}||13472-36-1
|-
|}

Beyond the diphosphates, sodium salts are known triphosphates, e.g. [[sodium triphosphate]] and tetraphosphates. The cyclic polyphosphates, called metaphosphates, include the trimer [[sodium trimetaphosphate]] and the tetramer, {{chem2|Na3P3O9}} and {{chem2|Na4P4O12}}, respectively.

Polymeric sodium phosphates are formed upon heating mixtures of {{chem2|NaH2PO4}} and {{chem2|Na2HPO4}}, which induces a [[condensation reaction]]. The specific polyphosphate generated depends on the details of the heating and annealing. One derivative is the [[glass]]y (i.e., amorphous) '''Graham's salt''' ([[sodium hexametaphosphate]]). It is a cyclic polyphosphate with the formula {{chem2|Na6[(PO3)6]}}. Crystalline high molecular weight polyphosphates include '''Kurrol's salt''' and '''Maddrell's salt''' (CAS#10361-03-2). These species have the formula {{chem2|[NaPO3]_{''n''}[NaPO3(OH)]2}} where ''n'' can be as great as 2000, and it is a white powder practically insoluble in water. In terms of their structures, these polymers consist of {{chem2|PO3−}} units, with the chains are terminated by protonated phosphates.<ref name=Ullmann/><ref name=G&E>{{Greenwood&Earnshaw2nd|page=530}}</ref>

==References==
<references />

==External links==
* {{Cite patent
|inventor= Bell, Russel N
|pubdate= 1973
|title= Sodium Aluminum Phosphate Cheese Emulsifying Agent
|number= 3726960
|country=US
}}
* {{Cite journal |last1= Lien |first1= YH |title= Is bowel preparation before colonoscopy a risky business for the kidney? |volume= 4 |issue= 11 |pages= 606–14 |date= 16 July 2008 |journal= Nature Clinical Practice Nephrology |doi= 10.1038/ncpneph0939 |pmid= 18797448|s2cid= 340122}}

{{Sodium compounds}}
{{Phosphates}}

[[Category:Phosphates]]
[[Category:Sodium compounds]]
[[Category:Edible thickening agents]]