Sodium Thiosulfate Anhydrous CAS 7772-98-7

2.Physical and Chemical Properties

• Appearance: Pentahydrate - colorless transparent crystals; anhydrous - white crystalline powder
• Melting point: Pentahydrate approximately 48.5 °C (melts in its own water of crystallization); anhydrous decomposes on heating
• Density: Anhydrous 1.667 g/cm³; pentahydrate 1.729 g/cm³
• Solubility: Highly soluble in water (pentahydrate about 70 g/100 mL at 20 °C); practically insoluble in ethanol Reducing property: A strong reducing agent that reacts readily with iodine, chlorine and hypochlorite Stability: Pentahydrate effloresces in dry air; store sealed in a cool, dry place

3.Main Functions and Applications (What are its uses?)

• Water treatment (core application): A dechlorination agent that removes residual chlorine, and a detoxifying agent for cyanide and heavy metals in wastewater.
• Photographic fixing agent (classic): Dissolves unexposed silver halides in film and print processing.
• Textile and dyeing: Used for dechlorination after bleaching and as a reducing agent.
• Pharmaceutical: Serves as an intravenous antidote for cyanide poisoning and as an anti-allergic agent.
• Gold extraction: Employed in thiosulfate leaching to recover gold from ores.
• Analytical chemistry: Used as a standard titrant in iodometric titrations.
• Leather tanning and electroplating: Applied as a reducing and complexing agent.

4.A Benchmark-Level Industrial Masterpiece - A Meticulously Crafted "Premium-Grade" Reducing Salt!

Na2S2O3·5H2O content reaches 99.0% or higher, meeting the premium grade and delivering dependable reducing power.

Low chloride, iron, sulfide and water-insoluble matter ensure clean dissolution and consistent dechlorination. High purity and rapid dechlorination/detoxification make it a trusted choice for water and effluent treatment. Available in both anhydrous and pentahydrate forms to suit specific process requirements.