Na2S2O3 – sodium thiosulfate – is an odorless compound, and can be either white or colorless. Sodium thiosulfate typically forms crystals together with 5 molecules of water, forming Na2S2O3 * 5H2O crystallohydrate. It is used in medicine to treat skin diseases. In addition, the substance boasts anti-toxic, anti-inflammatory, and anti-burn qualities. It is also used as a photographic fixer, as a reagent in analytical chemistry, and to remove iodine from fabrics.