Interactions de Van der Waals

Van der Waals interactions are weak intermolecular forces that arise from electrostatic interactions between atoms and molecules that are electrically neutral overall.

These interactions are broadly classified into three types: London dispersion forces, dipole–dipole forces, and dipole-induced dipole forces.

All molecules, even nonpolar ones, have temporary partial charges.

Due to the varying distribution of electrons, a higher electron density in one region of the electron cloud results in an instantaneous dipole or a temporary dipole.

This then causes another instantaneous dipole in the neighboring molecule. The domino effect of dipoles gives rise to weak intermolecular attractive forces, which exist between all molecules, whether polar or nonpolar.

These interactions between temporary dipoles are called London dispersion forces.

Dipoles in polar molecules like water electrostatically interact through dipole-dipole forces.

Dipole-induced dipole forces happen when a polar molecule, like water, disturbs the electronic arrangement of a non-polar molecule, like diatomic oxygen, and causes a dipole.

All these interactions are attractive when the atoms are close enough for their electron clouds to just contact. If the atoms get any closer, these forces become repulsive.