Intermolecular force

forces of attraction or repulsion which act between neighboring particles

In physics, chemistry, and biology, intermolecular forces are forces that act between stable molecules or between functional groups of macromolecules.

These forces are generally much weaker than the chemical bonding forces. Their bonding energies are less than a few kcal/mol. But they are responsible for many different physical, chemical, and biological phenomena. In general one distinguishes short and long range intermolecular forces. (The molecule is a substance are held together by the forces acting between the molecules which are called inter-molecular forces)

Hydrogen bonding

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Hydrogen bonding is an intermolecular interaction with a hydrogen atom being present in the intermolecular bond.  

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Other websites

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Software for calculation of intermolecular forces

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