Topics - Dipole-Dipole
Polar interactions between molecules can result from either dipole-dipole
interactions of dipole–induced dipole
interactions. Dipole-dipole interactions arise from localized permanent dipoles. The two opposite charges are on the same molecules and, thus, neutralize each other so there is no net
charge on the molecule as there is with an ion. However, the individual charges can interact with the individual charges of opposite sign on another molecule, and the interaction can be extremely strong. The energy of dipole-dipole interactions can approach the energy of a weak chemical bond. Due to the high energy of the dipole-dipole interactions, molecules can associate with each other (e.g., methanol-water association); this type of association is often called hydrogen bonding
. The energy of interaction is directly proportional to the product of the polarizability of the molecule and the square of the dipole moment. The interaction energy is also inversely proportional to the sixth power of the distance between the interacting charges.