$\begin{array}{1 1} Al_2Cl_6 : 3c-4e\; bond\; is\; present \\ Al_2(CH_3)_6 : All \;carbon\; atoms\; are\; sp^3 \;hybridised \\ I_2Cl_6 : Nonplanar \\ Al_2Br_6 : Nonpolar \end{array} $
