Intermolecular forces are the forces of attraction or repulsion which act between neighboring particles (atoms, molecules, or ions ).

There are three types of intermolecular forces: London dispersion forces (LDF), dipole- dipole interactions, and hydrogen bonding. Molecules can have any mix of these three kinds of intermolecular forces, but all substances at least have LDF.

Covalent Bonds The three types of intramolecular forces are covalent, ionic, and metallic bonding.

Van der Waals forces’ is a general term used to define the attraction of intermolecular forces between molecules. There are two kinds of Van der Waals forces: weak London Dispersion Forces and stronger dipole-dipole forces.

Ion-dipole forces are stronger than dipole interactions because the charge of any ion is much greater than the charge of a dipole; the strength of the ion-dipole force is proportionate to ion charge. Ion-dipole bonding is also stronger than hydrogen bonding.

Ion-Dipole Interactions. Ion-Dipole Forces are involved in solutions where an ionic compound is dissolved into a polar solvent, like that of a solution of table salt (NaCl) in water.

Intermolecular forces are the forces that exist between molecules. An ion-dipole force is a force between an ion and a polar molecule. A hydrogen bond is a dipole-dipole force and is an attraction between a slightly positive hydrogen on one molecule and a slightly negative atom on another molecule.

Instantaneous dipole-induced dipole forces or London dispersion forces: forces caused by correlated movements of the electrons in interacting molecules, which are the weakest of intermolecular forces and are categorized as van der Waals forces.

Van der Waals forces, relatively weak electric forces that attract neutral molecules to one another in gases, in liquefied and solidified gases, and in almost all organic liquids and solids.

The van der Waals force is the term used to describe weak but general forces acting between neutral atoms or molecules. Forces due to covalent bonds or electrostatic interactions between ions or ionic groups with one another or with neutral molecules are not included.

Van der Waals forces include attractive forces arising from interactions between the partial electric charges and repulsive forces arising from the Pauli exclusion principle and the exclusion of electrons in overlapping orbitals.

Van der Waals (VDW) forces are unique in one respect: they are always present, like gravitational forces. This is in contrast to other types of interatomic forces, such as covalent and ionic forces, which may or may not be present depending on the properties of the interacting atoms.