What kind of bond is created by a weak electrical attraction between polar molecules?

1 Answer
Aug 16, 2017

This would be called the dipole-dipole interaction.


The predominant intermolecular force between two polar molecules (unless it can undergo the stronger hydrogen bond) is the dipole-dipole interaction.

This type of force occurs between the positive end of one molecule and the negative end of another molecule:


In this image, the slightly positive hydrogen end (slightly positive because it has a lower electronegativity than #"Cl"#) is electrically attracted to the slightly negative chlorine end (slightly negative because it is more electronegative than #"H"#, which means electron density will be more concentrated toward #"Cl"#).

If the more electronegative atom (that is bonded to #"H"#) is #"N"#, #"O"#, or #"F"# (the nonmetals with the highest electronegativity), then the force is known as hydrogen bonding, which is stronger than dipole-dipole forces.

An example of this hydrogen bonding is seen in plain old water molecules: