Sodium thiosulfate
CAS 7772-98-7
EC 231-867-5
Formula H2O3S2.2Na
MW 158.11 g/mol
Salts & Minerals Water TreatmentPharmaceuticals & HealthcareTextile, Leather & PaperPrinting & Packaging Bleaching & WhiteningAntioxidant & StabilizerChelation & Sequestration
Description
Sodium thiosulfate (CAS 7772-98-7) is an inorganic sodium salt commercially known as Hypo or Antichlor, also referenced under trade designations such as BETZ 0235. It carries no E-code designation and is supplied as a white crystalline powder with the molecular formula H2O3S2.2Na.
In water treatment, sodium thiosulfate neutralises residual chlorine by reducing it to chloride ions, making treated water safe for discharge or reuse. In textile and paper processing, it terminates chlorine-based bleaching sequences by reacting stoichiometrically with hypochlorite, preventing fibre degradation. Pharmaceutical manufacturers also use it as an antioxidant stabiliser in injectable formulations.
Sodium thiosulfate is available in technical and pharmaceutical grades, with the latter conforming to Ph.Eur. and FCC monographs. The substance is registered under REACH and classified under HS code 28323000. Typical supply formats include 25 kg bags and bulk quantities for industrial procurement.
In water treatment, sodium thiosulfate neutralises residual chlorine by reducing it to chloride ions, making treated water safe for discharge or reuse. In textile and paper processing, it terminates chlorine-based bleaching sequences by reacting stoichiometrically with hypochlorite, preventing fibre degradation. Pharmaceutical manufacturers also use it as an antioxidant stabiliser in injectable formulations.
Sodium thiosulfate is available in technical and pharmaceutical grades, with the latter conforming to Ph.Eur. and FCC monographs. The substance is registered under REACH and classified under HS code 28323000. Typical supply formats include 25 kg bags and bulk quantities for industrial procurement.
Physical Properties
| Melting Point | 48 °C |
| Boiling Point | 100 °C |
| Density | 1.667 g/cm³ |
| Appearance | White powder |
| Color | White |
| Form | Solid |
| Water Solubility | Soluble in water. Insoluble in alcohol. |
| pH | 6.0-8.5 (25℃, 50mg/mL in H2O) |
| Log P | -0.428 (est) |
Trade & Regulatory
| HS Code | 28323000 |
| Storage Class | 11 - Combustible Solids |
| WGK (Germany) | 1 |
Other Names
HYPO'HYPO'ANTICHLORSODIUN THIOSULFATESODIUM HYPOSULFITESODIUM THIOSULPHATE
Related Products
Raw Materials
Derivatives
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