| Revision as of 14:38, 5 January 2014 editSmokefoot (talk | contribs)Autopatrolled, Extended confirmed users, Pending changes reviewers, Rollbackers74,236 edits Kurrol’s salt, Graham’s salt, Maddrell’s salt Sodium trimetaphosphate← Previous edit | Revision as of 16:54, 5 January 2014 edit undoSmokefoot (talk | contribs)Autopatrolled, Extended confirmed users, Pending changes reviewers, Rollbackers74,236 edits expanding the mention of the polyphosphatesNext edit → | ||
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| '''Sodium phosphate''' is a generic term for a variety of ]s of ] and ] (PO<sub>4</sub><sup>3-</sup>), hydrogen phosphate (HPO<sub>4</sub><sup>-</sup>), and dihydrogenphosphate (H<sub>2</sub>PO<sub>4</sub><sup>-</sup>). |
'''Sodium phosphate''' is a generic term for a variety of ]s of ] and ] (PO<sub>4</sub><sup>3-</sup>), hydrogen phosphate (HPO<sub>4</sub><sup>-</sup>), and dihydrogenphosphate (H<sub>2</sub>PO<sub>4</sub><sup>-</sup>). Phosphate also forms families or condensed anions including di-, tri-, tetra-, and polyphosphates. 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>Klaus Schrödter, Gerhard Bettermann, Thomas Staffel, Friedrich Wahl, Thomas Klein, Thomas Hofmann "Phosphoric Acid and Phosphates" in ''Ullmann’s Encyclopedia of Industrial Chemistry'' 2008, Wiley-VCH, Weinheim. {{DOI|10.1002/14356007.a19_465.pub3}}</ref> | ||
| ==Monophosphates== | |||
| Three families of sodium monophosphates are common, those derived from PO<sub>4</sub><sup>3-</sup>), hydrogen phosphate (HPO<sub>4</sub><sup>-</sup>), and dihydrogenphosphate (H<sub>2</sub>PO<sub>4</sub><sup>-</sup>). Some of the most well known salt are shown in the table. | |||
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| ==Di- and polyphosphates== | |||
| In addition to these phosphates, sodium forms a number of useful salts with ]s (called diphosphates) |
In addition to these phosphates, sodium forms a number of useful salts with ]s (called diphosphates), triphosphates and high polymers. Of these salts, those of the diphosphates are particularly common commercially. | ||
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| Beyond the |
Beyond the diphosphates, sodium salts are known triphosphates, e.g. ] and tetraphospates. The cyclic polyphosphates, called metaphosphates, include the trimer ] and the tetramer, Na<sub>3</sub>P<sub>3</sub>O<sub>9</sub> and Na<sub>4</sub>P<sub>4</sub>O<sub>12</sub>, respectively. | ||
| Polymeric sodium phosphates are also well known, these include Kurrol’s salt, Graham’s salt, and Maddrell’s salt. These species have the formula <sub>n</sub><sub>2</sub> where n can be as great as 2000. These polymers consist of PO<sub>3</sub><sup>-</sup> "monomers", but the chains are terminated by protonated phosphates.<ref name=Ullmann/> | |||
| ==Applications== | ==Applications== | ||
Revision as of 16:54, 5 January 2014
Sodium phosphate is a generic term for a variety of salts of Na and phosphate (PO4), hydrogen phosphate (HPO4), and dihydrogenphosphate (H2PO4). Phosphate also forms families or condensed anions including di-, tri-, tetra-, and polyphosphates. Most of these salts are known in both anhydrous (water-free) and hydrated forms. The hydrates are more common than the anhydrous forms.
Monophosphates
Three families of sodium monophosphates are common, those derived from PO4), hydrogen phosphate (HPO4), and dihydrogenphosphate (H2PO4). Some of the most well known salt are shown in the table.
| name | formula | CAS registry number |
|---|---|---|
| monosodium phosphate (anhydrous) | NaH2PO4 | 7558-80-7 |
| monosodium phosphate (monohydrate) | NaH2PO4(H2O) | |
| monosodium phosphate (dihydrate) | NaH2PO4(H2O)2 | |
| disodium phosphate (anhydrous) | Na2HPO4 | 7558-79-4 |
| disodium phosphate (dihydrate) | HNa2PO4(H2O)2 | 10028-24-7 |
| disodium phosphate (heptahydrate) | HNa2PO4(H2O)7 | 7782-85-6 |
| disodium phosphate (octahydrate) | HNa2PO4(H2O)8 | |
| disodium phosphate (dodecahydrate) | HNa2PO4(H2O)12 | 10039-32-4 |
| trisodium phosphate (anhydrous, hexagonal) | Na3PO4 | |
| trisodium phosphate (anhydrous, cubic) | Na3PO4 | 7601-54-9 |
| trisodium phosphate (hemihydrate) | Na3PO4(H2O)0.5 | |
| trisodium phosphate (hexahydrate) | Na3PO4(H2O)6 | |
| trisodium phosphate (octahydrate) | Na3PO4(H2O)8 | |
| trisodium phosphate (dodecahydrate) | Na3PO4(H2O)12 | 10101-89-0 |
Di- and polyphosphates
In addition to these phosphates, sodium forms a number of useful salts with pyrophosphates (called diphosphates), triphosphates and high polymers. Of these salts, those of the diphosphates are particularly common commercially.
| name | formula |
|---|---|
| monosodium diphosphate (anhydrous) | NaH3P2O7 |
| disodium diphosphate (anhydrous) | Na2H2P2O7 |
| disodium diphosphate (hexahydrate) | Na2H2P2O7(H2O)6 |
| trisodium diphosphate (anhydrous) | Na3HP2O7 |
| trisodium diphosphate (hydrate) | Na3HP2O7(H2O) |
| trisodium diphosphate nonahydrate | Na3HP2O7(H2O)9 |
| tetrasodium phosphate (anhydrous) | Na4P2O7 |
| tetrasodium diphosphate (decahydrate) | Na4P2O7(H2O)10 |
Beyond the diphosphates, sodium salts are known triphosphates, e.g. sodium triphosphate and tetraphospates. The cyclic polyphosphates, called metaphosphates, include the trimer sodium trimetaphosphate and the tetramer, Na3P3O9 and Na4P4O12, respectively.
Polymeric sodium phosphates are also well known, these include Kurrol’s salt, Graham’s salt, and Maddrell’s salt. These species have the formula n2 where n can be as great as 2000. These polymers consist of PO3 "monomers", but the chains are terminated by protonated phosphates.
Applications
Sodium phosphates have many applications in the food industry and for water treatment. For example, sodium phosphates are often used as leavening agents for baked goods. They are used to control pH of processed foods.
Safety
Sodium phosphates are popular in commerce in part because they are inexpensive and nontoxic.
Oral sodium phosphates 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. Since safe and effective replacements for phosphate purgatives are available, several medical authorities have recommended general disuse of oral phosphates.
References
- ^ Klaus Schrödter, Gerhard Bettermann, Thomas Staffel, Friedrich Wahl, Thomas Klein, Thomas Hofmann "Phosphoric Acid and Phosphates" in Ullmann’s Encyclopedia of Industrial Chemistry 2008, Wiley-VCH, Weinheim. doi:10.1002/14356007.a19_465.pub3
- Lucina E. Lampila "Applications and functions of food-grade phosphates" Ann. N.Y. Acad. Sci. 2013, vol. 1301, pp. 37–44. doi:10.1111/nyas.12230
-
Markowitz, GS; Perazella, MA (Aug 12), "Acute Phosphate Nephropathy", Kidney Int., vol. 76, no. 10, pp. 1027–34, doi:10.1038/ki.2009.308, PMID 19675530
{{citation}}: Check date values in:|date=and|year=/|date=mismatch (help) -
Mackey, AC; Green, L; Amand, KS; Avigan, M (2009), "Sodium phosphate tablets and acute Phosphate Nephropathy", Am J Gastroenterol, vol. 104, no. 8 (published Aug), pp. 1903–6, doi:10.1038/ajg.2009.342, PMID 19661931
{{citation}}: Check date values in:|publication-date=(help)
External links
- Bell, Russel N (1973), "SODIUM ALUMINUM PHOSPHATE CHEESE EMULSIFYING AGENT", US Patent 3726960 (published April)
{{citation}}: Check date values in:|publication-date=(help) - Lien, YH (2008), "Is bowel preparation before colonoscopy a risky business for the kidney?", Nature Clinical Practice Nephrology, 4 (11): 606–14, doi:10.1038/ncpneph0939, PMID 18797448.
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