Thiosulfate is an oxyanion of sulfur with the chemical formula S2O32−. Thiosulfate also refers to the compounds containing this anion, which are the salts of thiosulfuric acid, such as sodium thiosulfate and ammonium thiosulfate. Thiosulfate salts occur naturally. Thiosulfate rapidly dechlorinates water, and is used to halt bleaching in the paper-making industry. Thiosulfate salts are mainly used for dyeing in textiles, and bleaching of natural substances.