Fumed silica, also known as colloidal silicon dioxide, is made by high-temperature hydrolysis in a hydrogen-oxygen flame of silicon halides,
mainly methyl silicochloroform (CH3SiCl3) or tetrachlorosilane (SiCl4).
It is an amorphous nanoscale white powder with surface hydroxyl groups.
Fumed silica appears as white fluffy powder. It is a non-toxic, odorless, tasteless, and non-polluting inorganic oxide.