Van der Waals force

The sum of the attractive or repulsive forces between molecules (or between parts of the same molecule) other than those due to covalent bonds, the hydrogen bonds, or the electrostatic interaction of ions is called in chemistry “The Van der Waals force” (named after Dutch scientist Johannes Diderik van der Waals).

The term refers to the force between two permanent dipoles (Keesom force), the force between a permanent dipole and a corresponding induced dipole (Debye force)and the force between two instantaneously induced dipoles (London dispersion force).

The term itself is sometimes used as a synonym for the totality of intermolecular forces. Van der Waals forces are relatively weak compared to covalent bonds, but they do  play an important  role in categories  as diverse as supramolecular chemistry, structural biology, nanotechnology etc. Van der Waals forces define many properties of organic compounds, including their solubility in polar and non-polar media.

In low molecular weight alcohols, the hydrogen-bonding properties of the polar hydroxyl group dominate the weaker van der Waals interactions.

In 2012, the first direct measurements of the strength of the van der Waals force for a single organic molecule bound to a metal surface was made via atomic force microscopy.


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