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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

The majority of data on physico-chemical properties of dipotassium disulfite were taken from handbooks (including CRC Handbook of Chemistry and Physics, 2007 and the Merck Index, 2006).

New testing in accordance with OECD or EU guidelines was conducted to obtain information about:particle size distribution,auto flammability, flammability and explosive properties.

Waivers are proposed for boiling point, vapour pressure, partition coefficient, surface tension, flash point, oxidizing properties, stability in organic solvents, dissociation constant and viscosity, as well as for auto flammability, flammability and explosiveness.

Dipotassium disulfite(K2O5S2, molecular weight 222.325 g/mol),CAS No. 16731 -55 -8, EC No. 240 -795 -3

Dipotassium disulfite is a white, microcrystalline and - by visual inspection - homogeneous powder.


Decomposition at 150 °C (reliable handbook data)

Relative density: 2.3 (reliable handbook data)

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

D50= 104.3 µm

D10= 11.0 µm

D90= 336.7 µm

Dustiness: 67.63 mg/g, MMAD (GSD): 28.91 µm (1.61)

Water solubility: 495 g/L at 25 °C (verly soluble, reliable handbook data)

Additional information