Names | |
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IUPAC names
Diphosphoric acid
μ-oxido-bis(dihydroxidooxidophosphorus) | |
Other names
Pyrophosphoric acid
Phosphonophosphoric acid Phosphono dihydrogenphosphate | |
Identifiers | |
3D model (JSmol)
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ChEBI | |
ChEMBL | |
ChemSpider | |
DrugBank | |
ECHA InfoCard | 100.017.795 |
EC Number |
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82619 | |
KEGG | |
PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
H4P2O7 | |
Molar mass | 177.97 g/mol |
Melting point | 71.5 °C (160.7 °F; 344.6 K) |
Extremely soluble | |
Solubility | Very soluble in alcohol, ether |
Conjugate base | Pyrophosphate |
Hazards | |
GHS labelling:[1] | |
Danger | |
H302, H314 | |
P260, P264, P264+P265, P270, P280, P301+P317, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P321, P330, P363, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Pyrophosphoric acid, also known as diphosphoric acid, is the inorganic compound with the formula H4P2O7 or, more descriptively, [(HO)2P(O)]2O. Colorless and odorless, it is soluble in water, diethyl ether, and ethyl alcohol. The anhydrous acid crystallizes in two polymorphs, which melt at 54.3 and 71.5 °C. The compound is a component of polyphosphoric acid, an important source of phosphoric acid.[1] Anions, salts, and esters of pyrophosphoric acid are called pyrophosphates.