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Environmental fate & pathways

Adsorption / desorption

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Description of key information

Adsorption/desorption: Low potential for adsorption to organic carbon.

Key value for chemical safety assessment

Additional information

Testing is waived in accordance with Column 2 of REACH Annex IX. The substance has a low potential for adsorption

Hexachlorodisilane hydrolyses very rapidly to hexahydroxydisilane and HCl. The Si-Si bonds may also react to produce monosilicic acid and hydrogen gas. At concentrations above about 100-150 mg/l (measured as SiO2 equivalents), condensation products of monosilicic acid ((poly)silicic acid) and hexahydroxydisilane can form.

These hydrolysis products are inorganic substances which enter natural biogeochemical cycles

; adsorption/desorption studies are not relevant. Based on their structure and predicted water solubilities, the hydrolysis products will have a high affinity for water and a low affinity for organic carbon and so a low potential for adsorption to the organic carbon. However, they may interact with the mineral content of soil. Amorphous polysilicic acid is a constituent of most soils.