Disodium pyrophosphate
| Names | |
|---|---|
| IUPAC name Disodium dihydrogen diphosphate | |
| Other names Diphosphoric acid, disodium salt Disodium dihydrogen pyrophosphate Disodium diphosphate Sodium acid pyrophosphate, SAPP | |
| Identifiers | |
| 3D model (JSmol) | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.028.941 | 
| EC Number | 
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| E number | E450(i) (thickeners, ...) | 
| PubChem CID | |
| UNII | |
| CompTox Dashboard (EPA) | |
| 
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| 
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| Properties | |
| Na2H2P2O7 | |
| Molar mass | 221.936 g·mol−1 | 
| Appearance | White odorless powder | 
| Density | 2.31 g/cm3 | 
| Melting point | > 600 °C | 
| 11.9 g/(100 mL) (20 °C) | |
| Refractive index (nD) | 1.4645 (hexahydrate) | 
| Hazards | |
| Flash point | Non-flammable | 
| Lethal dose or concentration (LD, LC): | |
| LD50 (median dose) | 2650 mg/kg (mouse, oral) | 
| Related compounds | |
| Other anions | |
| Other cations | 
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| Related compounds | Tetrasodium pyrophosphate | 
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references | |
Disodium pyrophosphate or sodium acid pyrophosphate (SAPP) is an inorganic compound with the chemical formula Na2H2P2O7. It consists of sodium cations (Na+) and dihydrogen pyrophosphate anions (H2P2O2−7). It is a white, water-soluble solid that serves as a buffering and chelating agent, with many applications in the food industry. When crystallized from water, it forms a hexahydrate, but it dehydrates above room temperature. Pyrophosphate is a polyvalent anion with a high affinity for polyvalent cations, e.g. Ca2+.
Disodium pyrophosphate is produced by heating sodium dihydrogen phosphate:
- 2 NaH2PO4 → Na2H2P2O7 + H2O