Abstract: A process for the chemical modification of the surfaces of inorganic solid bodies containing --OH groups, which comprises silanizing the free --OH groups with an alkylhalosilane to covalently bond the alkyl groups thereof to the oxygen atoms of the hydroxyl groups; halogenating or sulfochlorinating the resultant bound alkyl groups to form corresponding haloalkyl or sulfochloroalkyl groups; and replacing the halogen atoms of the resultant haloalkyl or sulfochloroalkyl groups by substitution with a functional group to form a chemically modified, inorganic solid body suitable for use as a stationary phase component in catalysis or chromatography.