Title: Potassium Metabisulfite

CAS Registry Number: 16731-55-8

CAS Name: Potassium pyrosulfite

Molecular Formula: K2O5S2

Molecular Weight: 222.32

Percent Composition: K 35.17%, O 35.98%, S 28.85%

Line Formula: K2S2O5

Literature References: The article of commerce contains ~95% K2S2O5.

Properties: White crystals or cryst powder; sulfur dioxide odor; acid reaction; liberates SO2 with acids; oxidizes in air to sulfate, more readily in presence of moisture. It may catch fire if much heat develops in powdering it. Freely sol in water; insol in alcohol. Keep dry and well closed.

Use: As antifermentative in breweries and wineries; bleaching straw; preservative for fruits and vegetables.