Question

Draw the structures of $BC{l}_3\cdot N{H}_3$ and $AlC{l}_3$ (dimer).

Answer 1

Structure of $BC{l}_3\cdot N{H}_3$

In $BC{l}_3\cdot N{H}_3$, there is one coordinate bond between the N atom and B atom.

B has one empty P orbital, so it accepts one lone pair of electrons from a nitrogen atom to complete its octet.


Structure of $AlC{l}_3$

In $AlC{l}_3$, $Al$ is an electron deficient species and achieves stability by forming a dimer. Here $Al$ is in $s{p}^3$ hybrid state. Two bridging $Cl$ are forming $3$ centre$-4$ electron bonds.