Ion-Induced Dipole Attractions

The attraction that develops between an ion and non-polar molecule is called ion-dipole attractions and depends on the idea of induction.

In this case a negative ion gets close to a non-polar particle (NPP in the diagram)

and since the negative charge repels the electrons in the non-polar particle, it induces a charge in the non-polar particle.

In the diagram, the letters "NPP" represent the nucleus. Note that the nucleus has NOT moved. Only the electrons moves. This is what causes the non-polar particle to behave as if it is polar.

The ion and the (formerly) non-polar particle can then attract.

This attraction is called an ion-induced dipole attraction, because the ion has induced (forced) the non-polar particle to behave as a dipole.

This attraction can, of course, also happen with positive ions which attract (rather than push away) the electrons in the non-polar particle

Once the electrons in the NPP have shifted, the ion and the "induced" particle can attract.

This is, of course, also an ion-induced dipole attraction.