A type of chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond forms an electrostatic link with the more electreonegative atom of a polar covalent bond in the same or another molecule
A hydrogen bond is a weak type of chemical bond that is common in organisms. As the name suggests, this type of bond involves a hydrogen atom that is attracted to a strongly electronegative atom such as oxygen, fluorine, or nitrogen of a polar covalent bond in the same or another molecule. Nevertheless, the link between the hydrogen atom and an electronegative atom is a strong dipole-dipole attraction. However, this type of chemical attraction is weaker than other types of chemical bonds (such as covalent and ionic bonds).
Hydrogen bonds occur in inorganic molecules (e.g. water) and organic molecules (e.g. DNA and proteins). Hydrogen bonds in water accounts for the latter's high boiling point. Hydrogen bonds are also the ones responsible for the secondary and tertiary structures of important biomolecules such as nucleic acids and proteins. DNA, for instance, has a double helical structure that is largely due to the hydrogen bonds between paired nitrogenous bases.