Ion-Dipole Interactions

An ion-dipole interaction is the result of an electrostatic interaction between a charged ion and a molecule that has a dipole. It is an attractive force that is commonly found in solutions, especially ionic compounds dissolved in polar liquids. A cation can attract the partially negative end of a neutral polar molecule, while an anion attracts the positive end of a polar molecule. Ion-dipole attractions become stronger as the charge on the ion increases or as the magnitude of the dipole of the polar molecule increases. These interactions can be very significant factors in many chemical situations, so it is important to learn how to work with them.

Sodium only attracts the negatively charged end of water molecules, leading to the orientation shown. Public Domain Image.