Question

How is a dimer(AlCl3) formed?

Answer 1

Answer:

However, the electron deficiency of Aluminium atom in AlCl3 is compensated (completed) by formation of co-ordinate bond between lone pair of Chlorine atom of another AlCl3 molecule and the empty unhybridised p orbital of Aluminium atom, thus forming dimer ........like Kar ok

Answer 2

AlCl3 can form dimer and exists as Al2Cl6, aluminium has vacant d-orbitals which can accommodate electron from chlorine atom. AlCl3 is an electron deficient compound in Al (octet incomplete) thus behaves as Lewis acid and Al completes it by taking electron pair from Cl-atom as shown in figure.