intermolecular forces

chemistry

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June 29, 2026

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Intermolecular forces are weak attractions between molecules that, despite chemical bonds being satisfied, cause gases to liquefy and liquids to exist. These forces are significantly weaker than chemical bonds.1

There are several types of intermolecular forces:
* Dipole-dipole interactions: Occur between polar molecules where opposite partial charges attract.1
* Dispersion interactions (London forces): Arise from temporary fluctuations in electron distribution, creating transient dipoles that induce dipoles in neighboring molecules. These forces are present in all molecules, polar or not.23
* Repulsive forces: Become significant when molecules get very close, due to the overlap of electron wave functions and the Pauli exclusion principle.4

These forces, collectively known as van der Waals forces, are crucial for the properties of gases, liquids, and solids, particularly those with lower melting points and softer textures compared to substances with ionic, covalent, or metallic bonds.152

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chromatography
Retention
…normal forces existing between molecules—intermolecular forces. There are five major classes of these forces: (1) the universal, but weak, interaction between all electrons in 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…
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…normal forces existing between molecules—intermolecular forces. There are five major classes of these forces: (1) the universal, but weak, interaction between all electrons in 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…
Read More

elastomer
Intermolecular association: thermoplastic elastomers
Other rubbery materials consist of elastomers having strong intermolecular associations but no real chemical interlinks. Examples are molecules containing a few hydrogen-bonding groups. If the associations between the molecules are strong enough to prevent flow under
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Other rubbery materials consist of elastomers having strong intermolecular associations but no real chemical interlinks. Examples are molecules containing a few hydrogen-bonding groups. If the associations between the molecules are strong enough to prevent flow under
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chemistry of industrial polymers
Linear, branched, and network
…linear molecules can; hence, the intermolecular forces binding these polymers together tend to be much weaker. This is the reason why the highly branched LDPE is very flexible and finds use as packaging film, while the linear HDPE is tough enough to be shaped into such objects as bottles or…
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…linear molecules can; hence, the intermolecular forces binding these polymers together tend to be much weaker. This is the reason why the highly branched LDPE is very flexible and finds use as packaging film, while the linear HDPE is tough enough to be shaped into such objects as bottles or…
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liquid
Thermodynamics and intermolecular forces in solutions
The properties of solutions depend, essentially, on two characteristics: first, the manner in which the molecules arrange themselves (that is, the geometric array in which the molecules occupy space) and, second, the nature and strength of the forces operating between the…
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The properties of solutions depend, essentially, on two characteristics: first, the manner in which the molecules arrange themselves (that is, the geometric array in which the molecules occupy space) and, second, the nature and strength of the forces operating between the…
Read More