Tetrasodium pyrophosphate, also called sodium pyrophosphate, tetrasodium phosphate or TSPP, is an inorganic compound with the formula Na4P2O7. As a salt, it is a white, water-soluble solid. It is composed of pyrophosphate anion and sodium ions.
Molar mass: 265.900 g·mol−1
Appearance: Colorless or white crystals
Density: 2.534 g/cm3
Melting point: 988 °C (1,810 °F; 1,261 K) (anhydrous);79.5 °C (decahydrate)
Boiling point: decomposes
Solubility in water:2.61 g/100 mL (0 °C);6.7 g/100 mL (25 °C);42.2 g/100 mL (100 °C)
Solubility: insoluble in ammonia, alcohol
Refractive index (nD):1.425
Crystal structure:monoclinic (decahydrate)
Sodium pyrophosphate is used in water softener, detergent, emulsifying agent, metal cleaner and nutritional supplement. It acts as a buffering agent, thickening agent and dispersing agent. It also acts as a tartar control agent in toothpaste and dental floss. In addition, it is used as a chelating agent in antimicrobial studies. It is also used as a food additive in common foods such as chicken nuggets, crab meat and canned tuna.