Hydrogen bond

Among polar molecules, those with hydrogen atoms sometimes have interactions that are stronger than Van der Waals forces.

The hydrogen atom forms a "bridge" between two or more atoms although it only has one electron. This hydrogen bond is therefore not an ordinary bond. It only occurs with strongly electronegative atoms. A hydrogen bond can be established between a hydrogen atom covalently bound to a strongly electronegative atom A (F, O, N) and a strongly electronegative atom B having a non-bonding lone pair.

The length of the hydrogen bond is approximately 200 pm.