Difference Between Sigma and Pi Bond : Have you ever wondered how molecules stick together? Well, that's where sigma (σ) and pi (π) bonds come into play. They're like the glue that holds atoms in a molecule together. If you are aiming to appear in NEET , understanding the Difference Between Sigma and Pi Bond will help you to understand the behavior of molecules.
Here in this post, we will look into the details of these bonds, and how molecules act and react, so that you can make a strong hold on organic chemistry for NEET UG Exam preparation.NEET Chemistry Syllabus | NEET Chemistry Important Questions with Answers |
NEET Chemistry Chapter wise Weightage | NEET Chemistry MCQs |
NEET Chemistry Notes | NEET Chemistry Formulas |
Difference Between Sigma and Pi Bond | ||
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Parameters | Sigma (σ) Bond | Pi (π) Bond |
Bond Formation | Head-on overlap of atomic orbitals | Side-to-side overlap of parallel atomic orbitals |
Orbital Overlap | Occurs along the internuclear axis | Occurs above and below the internuclear axis |
Strength | Stronger than pi bonds | Weaker than Sigma bonds |
Electron Density | Maximum electron density between the nuclei | Electron density is above and below the nuclei |
Number of Bonds Formed | Single sigma bond between two atoms | Can have one or more pi bonds in addition to sigma bonds |
Hybridization | Involves hybridized orbitals (sp, sp2, sp3) | Often involves unhybridized p orbitals |
Multiple Bonding | Exists in all types of bonds (single, double, triple) | Contributes to double and triple bonds |
Rotation | No free rotation around the Sigma bond axis | Free rotation is possible around the pi-bond axis |
Example Molecules | Ethane (C2H6) | Ethene (C2H4), Acetylene (C2H2) |
HσH
Here, the line (σ) represents the sigma bond between the two hydrogen atoms. It signifies the direct overlap of the 1s orbitals, resulting in the formation of the sigma bond in the hydrogen molecule.Definition: A pi bond is formed when two atomic orbitals with parallel alignment overlap, allowing for the sharing of electrons above and below the internuclear axis.
Example: Consider the formation of a pi bond in an ethene (C2H4) molecule. Ethene consists of two carbon atoms double-bonded to each other. Each carbon atom has three sp2 hybrid orbitals, with one forming a sigma bond and the other two forming pi bonds.
H − C = C − H
In this Lewis structure, the double bond between the two carbon atoms consists of one sigma bond and one pi bond. The sigma bond is formed by the head-on overlap of sp2 hybrid orbitals, while the pi bond is formed by the side-to-side overlap of the unhybridized p orbitals on each carbon. The pi bond is represented by the double line ( ). So, in ethene, there is one sigma bond and one pi bond between the carbon atoms in the double bond, contributing to the overall structure and stability of the molecule. Elevate your NEET preparation with our NEET Online Coaching , and get access to expert guidance, comprehensive study materials, and interactive sessions from the comfort of your home. Our teachers are dedicated to boost your confidence, clarifying doubts instantly, and acing the NEET exam.