Ion-dipole interactions

Simply put an ion can be attracted to the end of the dipole that has a charge opposite the charge of the ion.

Induced dipole interactions

If a molecule remains close to a dipole or a charged particle a dipole can be induced. An analogy can be made between an induced dipole and an iron magnet; iron can be made into a magnet by leaving it in contact with a magnet. The ability of a substance to have a dipole induced in it is often referred to as its polarizability. The more polarizable the substance the easier it is to induce a dipole in the substance.

(A) non-polar iodine. The bonding electrons are distributed evenly between the two nuclei. (B) a dipole in iodine induced by Na+. The positive charge on the sodium ion attracts the electrons. Once the electrons move the electron distribution is uneven; thus the iodine molecule is now polar.

 

(A) non-polar iodine. The bonding electrons are distributed evenly between the two nuclei. (B) a dipole in iodine induced by the dipole of H₂O. The positive end of the dipole attracts the iodine's electrons. Once the electrons move the electron distribution is uneven; thus the iodine molecule is now polar.