Sodium Thiosulphate Pentahydrate 99%

Sodium thiosulfate (Na2S2O3), also spelled sodium thiosulphate, is a colorless crystalline compound that is more familiar as the pentahydrate, Na2S2O35H2O, an efflorescent, monoclinic crystalline substance also called sodium hyposulfite.

• As a component in hand warmers and other chemical heating pads that produce heat by exothermic crystallization of a supercooled solution.
• In bleach
• In pH testing of bleach substances.
• To dechlorinate tap water for aquariums or treat effluent from waste water treatments prior to release into rivers. The reduction reaction is analogous to the iodine reduction reaction. Treatment of tap water requires between 0.1 grams and 0.3 grams of pentahydrated (crystalline) sodium thiosulfate per 10 liters of water.
• To lower chlorine levels in swimming pools and spas following super chlorination.
• To remove iodine stains, e.g. after the explosion of nitrogen triiodide.
• In bacteriological water assessment.
• In the tanning of leather.
• To demonstrate the concept of reaction rate in chemistry classes.
• To demonstrate the concept of supercooling in physics classes. Melted sodium thiosulfate is very easy to overcool to room temperature and when crystallization is forced, the sudden temperature jump to 48.3 deg C can be experienced by touch.
• As part of patina recipes for copper alloys.
• Often used in pharmaceutical preparations as an anionic surfactant to aid in dispersion.
• It can also be used as a very interesting solute in supersaturation experiments.
• As an ingredient to table salt
• Gold Extraction
• Antidote to cyanide poisoning
• Photographic processing

Minimum Assay: >99.0%
Molecular Formula: Na2S2O3•5H2O 
Molecular Weight: 241.17 g/mol
Solubility in water (% weight): 79g/100 ml water @ 40 C
Melting Point: 48 °C
Calcium (Ca): <0.30%
Iron (Fe): <10ppm
Heavy Metals (as Pb): <10ppm
Acidity: <0.01%
Alkalinity: <0.06%

Cas Number: 10102-17-7

Einecs Number: 231-867-5

HS Code / Commodity Code: 2832300000

Hazard Phrases: H0001