Where are intermolecular forces found?

1 Answer
Jun 2, 2017

Intermolecular forces are found between molecules.


Molecules have a certain influence on their environment. You can, for example, have two molecules with a negative charge that will repel each other due to intermolecular Coulomb force.

There are many types of these interactions between molecules, if you want to know more about the different types, you could have a look at the list below!

  • Dipole-dipole interaction
    Two polar molecules (such as #H-Cl#) are attracted to each other by dipole-dipole forces, for example, #+ # and #-# are attracted to each other. These differences in partial charges are created by the difference in electronegativity of the atoms. See picture below.

  • Ion-dipole force
    This force also originates from the Coulomb force and is differs from the dipole-dipole interaction by having an ion (such as #Cl^-#) interaction with a dipole.

  • Ion-induced dipole force and dipole-induced dipole force.
    The principle of these two interactions is the same. On its own, an atom does not have a charge, but when placed close to an ion or dipole, the electron cloud gets deformed and the atom will become an induced dipole.

  • London dispersion force
    This force is created by electron collection. When two alkane molecules approach each other, repulsion of the electrons in one molecule by those in the other results in the correlation of their movement. Correlated electron motion in the bonds of the other induces polarisation in the opposite direction, resulting in attraction between the molecules.