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As per different websites on internet van der Waals force are of

  • Three types (Keesom force, Debye force and London dispersion force) @ Wikipedia
  • Two types (Dipole-dipole force/Keesome force and London dispersion force) @chemguide and chemwiki

While an expert website also explained H-bonds to be a van der Waals force.

I'm confused. What is originally correct?

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    $\begingroup$ Believe Wikipedia before some other "expert" website that says "van der Waals' forces are forces that exist between MOLECULES of the same substance." Since ethanol and water aren't the same substance, I was really surprised to learn that there can't be any hydrogen bonding between them. ;-) $\endgroup$ – MaxW Mar 31 '16 at 16:10
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    $\begingroup$ Wikipedia is right if you accept the IUPAC definitions:goldbook.iupac.org/V06597.html $\endgroup$ – user1420303 Apr 1 '16 at 0:27
  • $\begingroup$ When dealing with such forces and definitions, it is also important to remember that the distinctions are a bit artificial. In nature, you have the fundamental electromagnetic interaction and that's it. $\endgroup$ – TAR86 Apr 8 '17 at 8:20
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The definition of van der Waals forces according to IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8., is as follows:

The attractive or repulsive forces between molecular entities (or between groups within the same molecular entity) other than those due to bond formation or to the electrostatic interaction of ions or of ionic groups with one another or with neutral molecules. The term includes: dipole–dipole, dipole-induced dipole and London (instantaneous induced dipole-induced dipole) forces. The term is sometimes used loosely for the totality of nonspecific attractive or repulsive intermolecular forces.

The phrase "other than those due to bond formation or to the electrostatic interaction of ions or of ionic groups with one another or with neutral molecules" would seem to imply that according to the IUPAC Gold Book, if a force is not an ionic or covalent chemical bond or electrostatic interaction, then it is a van der Waals force.

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Slight correction on @airhuff's answer. "if a force is not an ionic or covalent chemical bond or electrostatic interaction, then it is a van der Waals force."

The IUPAC Gold Book's definition precludes "electrostatic interaction of ions or of ionic groups" from being VdW forces but all VdW forces are electrostatic in nature: forces between electrostatic dipoles, either permanent, induced or spontaneous.

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