Aluminium chloride exist as dimer Al₂Cl₆ in solid state as well as in solution of non-polar solvent such as C₆H₆. When dissolved in water it gives

 → Anhydrous AlCl₃ fumes in air.

White fumes appear around the bottle of anhydrous aluminium chloride.
 Anhydrous aluminium chloride is partially hydrolysed with atmospheric moisture to liberate HCl gas. Moist HCl appears white in colour.

→ It has Al—Cl terminal bonds and Al—Cl bridge bonds.

Al—Cl bridge bond length > Al—Cl terminal bond length.

→ Bridge bond is non electron deficient bond i.e.,3C — 4e¯ bond.

→ In vapour state and in non polar solvents anhydrous AlCl₃ exist as dimer and shows covalent nature and acts as non conductor.

→ In polar solvents like H₂O dimer undergoes cleavage by hydrolysis and forms