Chapter 17, Problem 8E

Aluminum chloride, ${\text{AlCl}}_{\text{3}}$, behaves more as a molecular compound than an ionic one. This is illustrated in its ability to form a fourth covalent bond with a chloride ion: ${\text{AlCl}}_{\text{3}}+{\text{ Cl}}^{-}\to {\text{AlCl}}_4{}^{-}$. From the Lewis diagram of the aluminum chloride molecule and the electron configuration of the chloride ion, show that this is an acid–base reaction in the Lewis sense, and identify the Lewis acid and the Lewis base.

Aluminum chloride is a white solid at room conditions, although it is typically manufactured mixed with some yellow iron(III) chloride. Its appearance is that of an ionic compound.