Sodium Thiosulfate Pentahydrate

Sodium thiosulfate pentahydrate (Na2S2O3), also spelled Sodium Thiosulphate Pentahydrate, is a colorless crystalline compound that is more familiar as the pentahydrate, Na2S2O3•5H2O.  It is an efflorescent, monoclinic crystalline substance also called Sodium Hyposulphite or “Hypo.”
Sodium thiosulfate or Sodium Thiosulphate is generally used as pentahydrate, in certain applications like photography, pharmaceutical, table salt  and some other applications, it is used as anhydrous sodium thiosulfate or Sodium Thiosulphate Anhydrous.

Sodium Thiosulfate Pentahydrate

Typical Analysis

Crystal Photo


(Pea Shape)

Assay, Na2S203 .5H20 min.


PH of 10% solution


Sodium Sulfite (Na2S03) max.

10 ppm

Iron (Fe), Max % by wt. max.


Heavy Metals (as Pb) max.

10 ppm

Photographic industry- as solubilized undeveloped silver salts in fixing of films and print.
Paper industry and water treatment - as antichlor.
Textile industry -as mordant in dyeing and printing textiles.
Tanning industry - as reducer of hexavalent chromium.

Analytical chemistry - as reagent.

Other hot product: Sodium Metabisulphite |Sodium Bicarbonate