Give reasons: `SiF_(6)^(2-)` known, out `SiCl_(6)^(2-)` is not known.

Explanation

Silicon (Si) atom can not hold six atoms of chlorine (Cl) due to their large size. But it can hold six atoms of fluorine (F) due to its small size. Also F is highly electronegative (4.0), which can cause the transfer of electrons from filled to empty orbitals.