Sodium Thiosulphate
Na₂S₂O₃ | CAS: 7772-98-7 | HS: 28321000
Product Description
Sodium Thiosulphate is chemically distinct from sulphites — its thiosulphate anion is a powerful complexing agent for silver halides (photographic fixing) and a reducing agent for halogens (dechlorination). Its pharmaceutical use as an antidote for cyanide poisoning and as a treatment for calciphylaxis (calcification disorder) makes it an essential hospital drug. In analytical chemistry, standardised sodium thiosulphate solution is the reagent for iodometric titration. MITCHEM supplies technical and pharma grades with appropriate documentation for industrial and pharmaceutical end users.
Applications by Industry
The classic photographic fixing agent (hypo) — dissolves unexposed silver halide crystals from photographic emulsions after development, making images stable and permanent.
Rapidly reduces chlorine and chloramine to chloride in water treatment and aquaculture systems; used to neutralise chlorinated process water before discharge and in emergency dechlorination.
IV sodium thiosulphate is administered as part of the cyanide poisoning antidote protocol — reacts with cyanide (via rhodanese enzyme) to form non-toxic thiocyanate for renal excretion.
Standardised thiosulphate solution is the titrant in iodometric titrations for quantifying oxidising agents (iodine, hypochlorite, dichromate) and dissolved oxygen (Winkler method).