Hydrogen bond can be defined as the attractive force which binds hydrogen atom of one molecule with the electronegative atom (F, O or N) of another molecule. It is represented by dotted lines. The chains possess a zig-zag structure.
(Hydrogen bond is purely electrostatic and a weak bond. The strength of the strongest hydrogen bond is about 5-10 kcal per mol. The more the electronegativity of atom involved in H-bonding, the more is the bond strength, e.g.,
Types of hydrogen bonds are
- Intermolecular H-bonding: H-bonding involving two or more molecules.
- Intramolecular H-bonding: H-bonding within a molecule.
It is formed between two different molecules of the same or different compounds. For example, H-bond in case of HF molecule, alcohol or water molecules, etc.
It is formed when hydrogen atom is in between the two highly electronegative (F, O, N) atoms present within the same molecule. For example, in o-nitrophenol the hydrogen is in between the two oxygen atoms.
Strength of bonds
Ionic bond > covalent bond > metallic bond > H-bond