Question

Alcl3 exist as dimer Explain it

Answer 1

••.•´¯`•.•• нєу ••.•´¯`•.••

AlCl3 is borderline for being ionic/covalent. When solid it is usually ionic. In vapor it is covalent. In this state 3 electrons from Al are shared with 3 Cl electrons. That makes only 6 electrons. To get to the very favorable 8 electron octet, it forms Al2Cl6 and thus the extra sharing from the dimer gives the necessary octet for all atoms.

Answer 2

Aluminium chloride is electron deficient so it is very unstable .
So, AlCl3 achieves stability by forming a dimer.

.
.