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]]