The key difference between dipole dipole interactions and hydrogen bonding is that dipole dipole interactions occur when partially negatively charged molecules interact with a neighboring molecule with a positive charge, whereas hydrogen bonding is a special type of strong dipole dipole bonding that occurs between O, N, and F and H atoms.
Dipole-dipole interactions and hydrogen bonds are very important phenomena when studying molecular bonding, molecular behaviors, crystal structures, and many other chemical facts.
CONTENTS
1. Overview and Key Difference
2. What are Dipole Dipole Interactions
3. What is Hydrogen Bonding
4. Dipole Dipole Interactions vs Hydrogen Bonding in Tabular Form
5. Summary – Dipole Dipole Interactions vs Hydrogen Bonding
What are Dipole Dipole Interactions?
Dipole-dipole interactions or dipole-dipole forces are intermolecular forces that occur between polar molecules. These are electrostatic forces. When forming this type of force, polar molecules tend to be aligned so that the attraction between the molecules is maximized by reducing the potential energy. This alignment also reduces the repulsions between the molecules.
When considering a series of compounds with similar molar masses (which have dipole-dipole interaction forces between molecules), the strength of dipole-dipole forces increases as the polarity increases. That happens because the charge separation is high when the polarity is high. When the molecule has a high charge separation (highly charged positive and negative terminals in the same molecule), it tends to strongly attract opposite charges. This also leads to an increase in the boiling point of compounds. Greater the dipole-dipole forces, the greater the boiling point.
What is Hydrogen Bonding?
A hydrogen bond can be described as a type of attraction force between two atoms of two different molecules. It is a weak attraction force. However, when compared to other types of intramolecular forces, such as polar-polar interactions and nonpolar-nonpolar interactions like Vander Waal forces, the hydrogen bond is much stronger.
Typically, hydrogen bonds form between polar covalent molecules. These molecules contain polar covalent bonds, which form as a result of the difference in the electronegativity values of the atoms that are in the covalent bond. If this difference is high, the highly electronegative atom tends to attract the bond electrons toward itself. Thus, this creates a dipole moment where this highly electronegative atom gets a partial negative charge, whereas the other atom gets a partial positive charge. Then the bond becomes a polar covalent bond. When this molecule meets another molecule that has a dipole moment like this, the negative and positive charges tend to attract each other. This attraction force is called a hydrogen bond.
Moreover, hydrogen bonds are formed between highly electronegative atoms and less electronegative atoms. Further, they exist when we have O, N, and F in one molecule and positive charged H in the other molecule. This is because F, N, and O are the most electronegative atoms that are capable of forming hydrogen bonds.
What is the Difference Between Dipole Dipole Interactions and Hydrogen Bonding?
The key difference between dipole dipole interactions and hydrogen bonding is that dipole dipole interactions occur when partially negatively charged molecules interact with a neighboring molecule with a positive charge, whereas hydrogen bonding is a special type of strong dipole-dipole bonding that occurs between O, N, F, and H atoms.
The below infographic presents the differences between dipole dipole interactions and hydrogen bonding in tabular form for side-by-side comparison.
Summary – Dipole Dipole Interactions vs Hydrogen Bonding
Dipole-dipole interactions are intermolecular forces that occur between polar molecules, while hydrogen bonding is a type of attraction force between two atoms of two different molecules. The key difference between dipole dipole interactions and hydrogen bonding is that dipole dipole interactions occur when partially negatively charged molecules interact with a neighboring molecule with a positive charge, whereas hydrogen bonding is a special type of strong dipole dipole bonding that occurs between O, N, and F and H atoms.
Reference:
1. “Hydrogen Bonding.” Chemistry LibreTexts, Libretexts, 11 Sept. 2022.
Image Courtesy:
1. “Dipole interactions” By Adam Rędzikowski – file:Dipole_interactions.png (CC BY-SA 3.0) via Commons Wikimedia
2. “210 Hydrogen Bonds Between Water Molecules-01” By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia