Key Difference – Intermolecular vs Intramolecular Hydrogen Bonding
Hydrogen bonding is a form of attraction force between certain polar molecules. it is a type of weak bonding than ionic or covalent bonds, but are strong attraction forces when compared to dipole-dipole forces and Van der Waal forces. A hydrogen bond is formed if the polar molecule has a strongly electronegative atom having a lone electron pair (which can act as an electron donor) bonded to a hydrogen atom (an electron acceptor). since the strongly electronegative atom can attract the bond electron par towards itself than that of a hydrogen atom, the hydrogen atom gets a partial positive charge, resulting in a strong charge separation. Hence, the common hydrogen bond forming chemical bonds are O-H bond, N-H bond, and F-H bond. There are two forms of hydrogen bonds that can be formed; intermolecular hydrogen bonding that occurs between polar molecules and intramolecular hydrogen bonding that occurs in the same single molecule. The key difference between intermolecular and intramolecular hydrogen bonding is that intermolecular hydrogen bonding occurs in between two molecules whereas intramolecular hydrogen bonding occurs in a single molecule.
CONTENTS
1. Overview and Key Difference
2. What is Intermolecular Hydrogen Bonding
3. What is Intramolecular Hydrogen Bonding
4. Side by Side Comparison – Intermolecular vs Intramolecular Hydrogen Bonding in Tabular Form
5. Summary
What is Intermolecular Hydrogen Bonding?
Intermolecular hydrogen bonds occur between separate molecules in a substance. Therefore, the electron donor and electron acceptor should be present in two separate molecules. If proper electron donors and acceptors are present, any molecule can form hydrogen bonds.
Figure 01: Intermolecular Hydrogen Bonding in Water Molecules
A common example for molecules that can form intermolecular hydrogen bonds are water molecules (H2O).The hydrogen bonds in between the water molecules cause the formation of a rigid structure when liquid water is converted into solid ice.
What is Intramolecular Hydrogen Bonding?
Intramolecular hydrogen bonds are those occurring within a single molecule.This type of hydrogen bonding arises when two functional groups that are capable of forming hydrogen bonds with each other are present in the same single molecule. This means both electron donor and electron acceptor should be present in the same molecule.
Figure 02: Intramolecular Hydrogen Bonding in Salicylaldehyde
Moreover, these two functional groups should be positioned close enough to for this hydrogen bond. The most common example of a molecule that shows this type of hydrogen bonding is salicylaldehyde(C7H6O2).
What is the Difference Between Intermolecular and Intramolecular Hydrogen Bonding?
Intermolecular vs Intramolecular Hydrogen Bonding |
|
| Intermolecular hydrogen bonds occur between separate molecules in a substance. | Intramolecular hydrogen bonds are those that occur within one single molecule. |
| Components | |
| Intermolecular hydrogen bonds are formed between two molecules. | Intramolecular hydrogen bonds are formed between separate molecules. |
Summary – Intermolecular vs Intramolecular Hydrogen Bonding
Hydrogen bonding is a form of dipole-dipole interaction. But it is a weak bond type. There are two forms of hydrogen bonding as intermolecular and intramolecular hydrogen bonds. The difference between intermolecular and intramolecular hydrogen bonding is that intermolecular hydrogen bonding occurs in between two molecules whereas intramolecular hydrogen bonding occurs in a single molecule.
Reference:
1.“Hydrogen Bonding.” Chemistry LibreTexts, Libretexts, 21 July 2016. Available here
2.“Hydrogen Bond.” Wikipedia, Wikimedia Foundation, 14 Mar. 2018. Available here
Image Courtesy:
1.’Hydrogen-bonding-in-water-2D’ (Public Domain) via Commons Wikimedia
2.’Salicylaldehyd Wasserstoffbrücke’By NEUROtiker ⇌ – Own work, (Public Domain) via Commons Wikimedia