Question

Silicon forms SiF62^- ion where as corresponding fluoro compounds of carbon is not known

Answer 1

Dear Student,

Silicon has vacant 3d-orbitals in the valence shell and thus expands its octet giving sp³d² hybridisation accepting lone pair of electrons in vacant d orbitals, while vacant d-orbitals are not present in the valence shell of carbon atom. It cannot expand its octet. It can only form four bonds. Thus, carbon is unable to form CF₆^2- anion by accepting electrons like Silicon.

Regards
Rashmi Sheokand