* Binary: It consists of only two elements: aluminum (Al) and chlorine (Cl).
* Ionic: Aluminum is a metal, and chlorine is a nonmetal. Metals tend to lose electrons and form cations (positively charged ions), while nonmetals tend to gain electrons and form anions (negatively charged ions). In aluminum chloride, aluminum forms a +3 cation (Al³⁺) and chlorine forms a -1 anion (Cl⁻). These ions are held together by electrostatic attraction, forming an ionic bond.
Therefore, aluminum chloride fulfills both criteria for being a binary ionic compound.
