Chemical database: Potassium metabisulphite

Chemical formula K2S2O5 Molar mass 222.32 g mol -1 Density 2.34 g cm -3 Melting point decomposition (~ 150 °C) Boiling point - Solubility 45.0 g in 100 mL H2O (20 °C) CAS number 16731-55-8 Hazards

Potassium metabisulphite is an inorganic compound which comes in form of small white crystals at standard conditions. Potassium metabisulphite is used as an antioxidant and as a chemical sterilant. The mentioned properties are useful in the production of wine and beer. Sulphur dioxide, which K₂S₂O₅ releases, inhibits the growth of microorganisms. This compound is also used in photographic processing.

Since potassium metabisulphite is used in the sterilization of wine barrels, it can be bought in stores which sell equipment for winemaking. It can also often be found in stores which sell agricultural equipment, but sometimes in common grocery stores as well. Potassium metabisulphite of higher purity can be ordered from specialized chemical selling companies, usually only in larger amounts.