Chemical Bonding and Molecular Structure Part 1

Charge of cation/Size of cation is called polarising power.
∴ (i) Polarising power ∝ charge of cation
(ii) Polarising power ∝‌

1

‌ size of cation ‌

Here the AICl3 is satisfying the above two conditions i.e., Al is in +3 oxidation state and also has small size. So it has more covalent character.