Intermolecular forces (IMF) are the forces which mediate interaction between
The investigation of intermolecular forces starts from macroscopic observations which indicate the existence and action of forces at a molecular level. These observations include non-ideal-gas thermodynamic behavior reflected by
The first reference to the nature of microscopic forces is found in
Attractive intermolecular forces are categorized into the following types:
Information on intermolecular forces is obtained by macroscopic measurements of properties like viscosity,
Dipole–dipole interactions are electrostatic interactions between molecules which have permanent dipole(s).These interactions tend to align the molecules to increase attraction (reducing
Often molecules contain dipolar groups, but have no overall
Ion-dipole and ion-induced dipole forces are similar to dipole-dipole and dipole-induced dipole interactions but involve ions, instead of only polar and non-polar molecules. Ion-dipole and ion-induced dipole forces are stronger than dipole-dipole interactions because the charge of any ion is much greater than the charge of a dipole moment. Ion-dipole bonding is stronger than hydrogen bonding.
An ion–dipole force consists of an ion and a polar molecule interacting. They align so that the positive and negative groups are next to one another, allowing maximum attraction.
An ion-induced dipole force consists of an ion and a non-polar molecule interacting. Like a dipole-induced dipole force, the charge of the ion causes distortion of the electron cloud on the non-polar molecule.
A hydrogen bond is the attraction between the lone pair of an
Intermolecular hydrogen bonding is responsible for the high boiling point of