Pyrophosphoric acid
1746240
224997830
2008-07-11T11:23:51Z
79.12.12.129
{{Chembox new
| ImageFile = Pyrophosphoric-acid-2D.png
| ImageName = Chemical structure of pyrophosphoric acid
| ImageFile1 = Pyrophosphoric-acid-3D-vdW.png
| ImageName1 = 3D model of pyrophosphoric acid
| IUPACName = diphosphoric acid<br />μ-oxido-bis(dihydroxidooxidophosphorus)
| OtherNames = diphosphoric acid
| Section1 = {{Chembox Identifiers
| SMILES = OP(=O)(O)OP(=O)(O)O
| CASNo = 2466-09-3
}}
| Section2 = {{Chembox Properties
| Formula = H<sub>4</sub>P<sub>2</sub>O<sub>7</sub>
| MolarMass = 177.98 g/mol
| Density =
| MeltingPt = 61 °C
| BoilingPt = °C
}}
}}
'''Pyrophosphoric acid''', also known under the name '''diphosphoric acid''', is a syrupy liquid or a viscous off-white solid.<ref>[http://www.sciencelab.com/xMSDS-Pyrophosphoric_acid-9924773 Material Safety Data Sheet: Pyrophosphoric acid MSDS]</ref> Pyrophosphoric acid is colorless, odorless, [[hygroscopic]] and is soluble in [[water (molecule)|water]], [[diethyl ether]], and [[ethyl alcohol]]. It is the [[anhydride]] of [[phosphoric acid]] and is produced from phosphoric acid by [[Dehydration reaction|dehydration]]. Pyrophosphoric acid slowly [[Hydrolysis|hydrolyzes]] in the presence of water into phosphoric acid.
: 2H<sub>3</sub>PO<sub>4</sub> ⇌ H<sub>4</sub>P<sub>2</sub>O<sub>7</sub> + H<sub>2</sub>O
Pyrophosphoric acid is a medium strong [[Inorganic chemistry|inorganic]] [[acid]]. The [[anion]], the [[salt]]s, and the [[ester]]s of pyrophosphoric acid are called [[pyrophosphate]]s.
==See also==
* [[Sodium pyrophosphate]]
* [[Calcium pyrophosphate dihydrate deposition disease]]
* [[Dimethylallyl pyrophosphate]]
* [[Adenosine diphosphate|ADP]]
* [[Adenosine triphosphate|ATP]]
* [[Ortho acid]]s
==References==
<references/>
==External links==
*[http://www.cem.msu.edu/~reusch/VirtualText/acidity.htm Dissociation constants]
*[http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=217793 Pyrophosphoric acid at PubChem]
[[Category:Phosphates]]
[[Category:Acids]]
[[de:Diphosphorsäure]]
[[es:Ácido pirofosfórico]]
[[fr:Acide pyrophosphorique]]
[[it:Acido pirofosforico]]
[[lt:Pirofosforo rūgštis]]
[[ja:ピロリン酸]]
[[pt:Ácido pirofosfórico]]
[[zh:焦磷酸]]