Tetrasodium pyrophosphate

Tetrasodium pyrophosphate
IUPAC name	Tetrasodium diphosphate
Identifiers
CAS number	7722-88-5 Y, 13472-36-1 (decahydrate)
Properties
Molecular formula	Na4P2O7
Molar mass	265.90 g/mol
Appearance	Colourless crystals
Hazards
EU Index	Not listed
Flash point	Non-flammable
Related compounds
Other anions	Trisodium phosphate Pentasodium triphosphate Hexasodium metaphosphate
Other cations	Tetrapotassium pyrophosphate
Related compounds	Disodium pyrophosphate
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Tetrasodium pyrophosphate, also called sodium pyrophosphate or tetrasodium phosphate, is a slightly toxic and mildly irritating colorless transparent crystalline chemical compound with the formula Na₄P₂O₇. It contains the pyrophosphate ion. Toxicity is approximately twice that of table salt when ingested orally.^[1]. There is also a hydrated form, Na₄P₂O₇.10(H₂O).^[2]

Sodium pyrophosphate is used as a buffering agent, an emulsifier, and a thickening agent, and is often used as a food additive. Common foods containing sodium pyrophosphate include chicken nuggets, marshmallows, pudding, crab meat, imitation crab, canned tuna, and soy-based meat alternatives. It is the active ingredient in Bakewell, the substitute for baking powder's acid component marketed during shortages in World War II.

In toothpaste and dental floss, sodium pyrophosphate acts as a tartar control agent, serving to remove calcium and magnesium from saliva and thus preventing them from being deposited on teeth. Sodium pyrophosphate is sometimes used in household detergents to prevent similar deposition on clothing, but due to its phosphate content it causes eutrophication of water, promoting algae growth.

Calcium pyrophosphate is the crystal deposited in joints in the medical condition pseudogout.^[3]

See also

• pseudogout
• food allergy

References

1. ^ http://books.google.com/books?id=Mk-IdNTTJB0C&pg=PA259&lpg=PA259&dq=tetrasodium+phosphate+toxicity&source=web&ots=UTcG2wT0y9&sig=_c9T9HRdwiV7pMk01T8ZLTzFkl8#PPA260,M1
2. ^ D.L. Perry S.L. Phillips (1995) Handbook of inorganic compounds CRC Press ISBN 0849386713
3. ^ Clinical Medicine, Kumar and Clark, 6th Ed., p. 571