Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Disodium hexafluorosilicate undergoes dissociation as follows:

 Na2SiF6→ 2NaF + SiF4

After, it undergoes further hydrolysis, providing the following overall reaction:

Na2SiF6+ 4H2O → 6NaF + Si(OH)4

The extent that it occurs depends highly on the pH, since although dissociation of salts readily occurs in aqueous solution, hydrolysis is very much influenced by pH. However, at environmental pH, hydrolysis is complete affording 100% fluoride.

Since disodium hexafluorosilicate is an inorganic substance, it does not undergo biodegradation (microbial degradation to CO2and H2O) as it does not contain any C or H atoms. It is degradated by means other than biodegradation.

The total dissociation and hydrolysis of disodium hexafluorosilicate at environmental pH prevents that it adsorbs onto particulates or accumulate as such in living tissues.

Nonetheless, fluorides, as degradation products, may be absorbed in living tissues.Metabolism of fluoride has been studies in IPCS_INCHEM_1984.