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Physical & Chemical properties

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The majority of data on the physical and chemical properties of sodium thiosulfate were taken from handbooks (including CRC Handbook of Chemistry and Physics and the Merck Index).

A study conducted in accordance with EU guidelines are available for: particle size distribution

Waivers are proposed for following endpoints: boiling point, vapour pressure, partition coefficient, surface tension, flash point, auto flammability, flammability, explosiveness, oxidising properties, stability in organic solvents, dissociation constant and viscosity as well as for pyrophoric properties and flammability in contact with water.

Sodium thiosulfate (Na2S2O3, molecular weight 158.11 g/mol), CAS number 7772-98-7, EC number 231-867-5

Sodium thiosulfate appears as a colourless monoclinic crystalline solid.

Decomposition temperature: Sodium thiosulfate decomposes during the measurement up to 500°C. (experimental study results, according to OECD guidelines 113 and 102); sodium thiosulfate decomposes at 100 °C (reliable handbook data).

Relative density: 1.69 (reliable handbook data)

Particle size distribution and dustiness of a representative sample (experimental study results):

D50 = 750.7 µm

D10 = 170.9 µm

D90 = 1453.9 µm

Dustiness: 23.78 mg/g, MMAD (GSD): 28.16 µm (1.89)

Water solubility: 764 g/L at 25°C (very soluble, reliable handbook data)