London force

References

London force

intermolecular force

Also known as: dispersion force, induced-dipole-induced dipole interaction(Show More)

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 30, 2026

Quick Summary

The term "London force" refers to a type of intermolecular force, also known as dispersion interaction or induced-dipole–induced-dipole interaction. These are relatively weak electric forces that attract neutral molecules to one another.12

London forces arise from fluctuations in electron density within molecules. Even in nonpolar molecules, electrons are constantly moving, creating temporary, instantaneous dipoles. These transient dipoles can then induce corresponding dipoles in neighboring molecules, leading to a weak attractive force between them. This interaction is present in all types of molecules, whether polar or nonpolar, and is a primary reason why gases can liquefy and why many molecular compounds exist as solids. These forces are generally weaker than chemical bonds like ionic, covalent, or metallic bonds.21

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

3 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

chemical association
…low temperatures the relatively weak London forces (i.e., forces acting between any two atoms brought close together) may also be strong enough to produce molecular association.
Read More
…low temperatures the relatively weak London forces (i.e., forces acting between any two atoms brought close together) may also be strong enough to produce molecular association.
Read More

chromatography
Retention
…neighbouring atoms and molecules, called dispersion forces, (2) the induction effect, by which polar molecules (those having an asymmetrical distribution of electrons) bring about a charge asymmetry in other molecules, (3) an orientation effect, caused by the mutual attraction of polar molecules resulting from alignment of dipoles (positive charges separated…
Read More
…neighbouring atoms and molecules, called dispersion forces, (2) the induction effect, by which polar molecules (those having an asymmetrical distribution of electrons) bring about a charge asymmetry in other molecules, (3) an orientation effect, caused by the mutual attraction of polar molecules resulting from alignment of dipoles (positive charges separated…
Read More

van der Waals forces
…fluctuations in molecules (known as London forces, or dispersion forces) are present even between permanently polar molecules and produce, generally, the largest of the three contributions to intermolecular forces.
Read More
…fluctuations in molecules (known as London forces, or dispersion forces) are present even between permanently polar molecules and produce, generally, the largest of the three contributions to intermolecular forces.
Read More

chemical bonding
Dispersion interaction
The third type of interaction acts between all types of molecule, polar or not. It is also somewhat stronger than the two attractive interactions discussed thus far and is the principal force responsible for the existence of the condensed phases of certain molecular…
Read More
The third type of interaction acts between all types of molecule, polar or not. It is also somewhat stronger than the two attractive interactions discussed thus far and is the principal force responsible for the existence of the condensed phases of certain molecular…
Read More

liquid
Nonpolar molecules
…intermolecular forces of attraction called London (or dispersion) forces. All molecules, charged or not, polar or not, interact by London forces. To a first approximation, the London force between two molecules is inversely proportional to the seventh power of the distance of separation; it is therefore short-range, decreasing rapidly as…
Read More
…intermolecular forces of attraction called London (or dispersion) forces. All molecules, charged or not, polar or not, interact by London forces. To a first approximation, the London force between two molecules is inversely proportional to the seventh power of the distance of separation; it is therefore short-range, decreasing rapidly as…
Read More