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1.1.2.1. Van der Waals forces

Van del Waals forces

The Van der Waals force are weak electrostatic interactions attraction and short range.

We distinguish between:

  • Dipole-dipole forces: These are forces that appear between polar molecules (permanent dipoles). The greater the dipole moment of the molecule, the greater the attractive force.
  • Induced dipole-dipole forces: Polar molecules in the vicinity of nonpolar molecules can produce a charge shift in them, transforming it into a dipole. A weak attractive force appears between the permanent and the armature dipole.
  • Scattering forces: Scattering forces arise between apolar molecules. At a given moment, a molecule can suffer an asymmetry in its charge distribution, originating an instantaneous dipole, which can act on another neighboring molecule creating an induced dipole in it. Induction progresses to other chain molecules, giving rise to weak attractive forces. These forces increase with molecular size, since larger molecules deform more easily.