Here, in both molecules i.e., NH₃ and NF₃, the central atom (N) has a lone pair electron and there are three bond pairs in total. Therefore, both the molecules have a pyramidal shape. Since fluorine is more electronegative than hydrogen, it is expected that the net dipole moment of NF₃ is greater than NH₃. But in real, the net dipole moment of NH₃ (1.46 D) is greater than that of NF₃ (0.24 D).

This phenomenon is explained on the basis of the direction of dipole moments extended by each individual bonds of the molecules

. These directions can be shown as:

From this figure, the net dipole moment of N-H bonds can be found greater than that of counterpart N-F bonds, where there is partial cancelling rather than adding up of moments. Hence, the net dipole moment of NF₃ is less than that of NH₃.