The anion of Barium Chloride (BaCl₂) is chloride, which is represented by the symbol Cl⁻.

Here's why:

* Barium Chloride is an ionic compound. Ionic compounds are formed by the electrostatic attraction between positively charged ions (cations) and negatively charged ions (anions).

* Barium (Ba) is a metal and forms a cation with a +2 charge (Ba²⁺).

* Chlorine (Cl) is a nonmetal and forms an anion with a -1 charge (Cl⁻).

* To balance the charges and form a neutral compound, two chloride ions (2 x Cl⁻ = -2) are needed for every barium ion (Ba²⁺).

Therefore, the anion in Barium Chloride is the chloride ion (Cl⁻).