Sodium thiosulfate is an inorganic compound, typically available as the white or colorless pentahydrate. The solid is an efflorescent (loses water readily) crystalline substance that dissolves well in water.

On an industrial scale, sodium thiosulfate is produced chiefly from liquid waste products of sodium sulfide or sulfur dye.
In the laboratory, this salt can be prepared by heating an aqueous solution of sodium sulfite with sulfur or by boiling aqueous sodium hydroxide and sulfur.

SynonymsSodium hyposulfite pentahydrate
Disodium thiosulfate pentahydrate
CAS no.10102-17-7
EINECS no.231-867-5
Molecular formulaH10Na2O8S2
Molecular weight248.19
We find various applications of sodium thiosulphate in different fields such as medicine, photography, gold extraction and many other areas. Some uses of it are below:

– Sodium thiosulfate is used in the manufacture of patinas.

– In industries, the chemical is used for the dechlorination of small water bodies like ponds, aquariums, etc.

– In photography, the chemical is used as a fixing agent to dissolve the silver salts from the negatives.

– The chemical can be utilized as a cleansing agent when dissolved in a vast quantity of warm water.

– It is well-used as an antidote agent concerning the cyanide poisoning.

– In the medical field, it is employed in the pharmaceutical preparations such as anionic surfactant aiding in dispersion.
Apart from the above uses, the chemical substance also finds its applications in the water treatment, leather tanning, neutralizing bleach, gold extraction, photographic film processing, and  in chemical heating pads.


AppearanceColorless Solid
Assay%NLT 99.0
pH of a 5% solution at 25 °C6.0 – 8.4
Insoluble matter%Max 0.005
Nitrogen compounds%Max 0.002
Sulfate and Sulfite (as SO4)%Max 0.1
Sulfide (S)Passes test
Potassium (K)%Max 0.1

25 kg HDPE bags.

Stored at ambient temperature.

REACH Status
Not registered yet.

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