Question

Dimeric structure of aluminium chloride

Answer 1

This change in structure is related to the lower density of the liquid phase (1.78 g/cm3) vs solidaluminium trichloride (2.48 g/cm3). Al2Cl6 dimersare also found in the vapour phase. At higher temperatures, the Al2Cl6 dimers dissociate into trigonal planar AlCl3, which is structurally analogous to BF3.

Answer 2

The dimeric structure of $Al_2Cl_6$ is as follows-

• The compound $AlCl_3$ unit dimerise to form $Al_2Cl_6$.
• In this compound, there are four covalent bonds present between Al and Cl atoms. Two chlorine atoms act as a bridge and connect the two Al atoms by bridging.
• $Al_2Cl_6$ can exist in the vapour phase and at high temperatures, it disassociates to $AlCl_3$ units.
• #SPJ6