Halogenation

$$\text{C}_6\text{H}_6 + \text{X}_2 \xrightarrow{\text{Anhy. FeX}_3 \text{ or } \text{AlX}_3} \text{C}_6\text{H}_5\text{X} + \text{HX} \quad (\text{X} = \text{Cl, Br})$$

Electrophile: Halogenonium ion ($$\text{Cl}^+$$or$$\text{Br}^+$$) generated via $$\text{X}_2 + \text{FeX}_3 \to \text{X}^+ + [\text{FeX}_4]^-$$