If B–Cl bond has a dipole moment, explain why BCI3 molecule has zero dipole moment.


As a result of the difference in the electronegativities of B and Cl, the B–Cl bond is polar in nature. However, the BCI3 molecule is non-polar. This is because BCI3 is trigonal planar in shape. It is a symmetrical molecule. Hence, the respective dipole-moments of the B–Cl bond cancel each other, thereby causing a zero-dipole moment.