What is the difference between sigma bond and Pi bond?
Sigma bond and Pi bond are chemical covalent bond formed by the overlap of atomic orbitals. Both of these bonds are acquire named from Greek letter and the bond is viewed down the bond axis.
The article provides the core difference between sigma bond and Pi bond with the comparison table as well as point form for easier understanding.
What Is Sigma Bond?
Sigma bond is a chemical covalent bond formed from end to end overlapping of half-filled atomic orbitals of atoms participating in bonding.
The electron cloud formed as a result of axial overlap is cylindrically symmetrical about an internuclear axis.
What Is Pi Bond?
A pi bond is a chemical covalent bond formed by lateral overlapped of half-filled atomic orbitals of the atoms participating in bonding.
The bond consists of two charged clouds below and above the plane of the atoms involved in bond formation.
Comparison Chart
| Basic Terms | Sigma Bond | Pi Bond |
| Definition | A covalent bond formed by the end to end overlapping of half-filled atomic orbitals of atoms participating in bonding. | A covalent bond formed by lateral overlapped of half-filled atomic orbitals of the atoms participating in bonding. |
| Formation | Combination of s orbitals in different atoms. | Combination of p and similar orbitals in different atoms. |
| Molecular Orbital | It is symmetrical about the intermolecular axis. | It is discontinuous and consists of two charged clouds above and below the plane of atoms. |
| Reactivity | More reactive | Less reactive |
| Strength | Quite strong | Less strong |
| Number Of Bonds | Double bond | Triple bond |
| Symmetrical Rotation | Rotate symmetrically around the internuclear axis. | Cannot rotate symmetrically around an internuclear. |
| Effect of on Length of Molecule | Decides the shape of the molecule | Decides the length of the molecule |
| Relativity Of Compound Formed | It is inversely proportional to some sigma bonds whereas the stability of the compound is directly proportional to the number of sigma bonds. | It is directly proportional to some Pi bonds whereas the stability of the compound is inversely proportional to the number of pi bonds. |
| Formed | When the head of atomic orbitals overlaps with each other along the internuclear axis of the atoms. | Formed by the overlapping of atomic orbitals. |
| Occurrence First | When atoms get closer sigma bonds are formed first. | The formation of a pi bond is preceded by the formation of sigma bonds. |
Core Difference between Sigma Bond and Pi Bond
- Sigma bond tends to be stronger than Pi bond
- Sigma bond tends to have an independent existence in molecules while Pi bond is formed as an additional to sigma bond.
- Sigma bond decides the shape of the molecule while Pi bond decides the length of the molecule.
- Sigma bond has overlapping orbitals are oriented along the internuclear axis while Pi bond has overlapping orbitals are oriented laterally along the internuclear axis.
- Pi bond only p orbitals are formed in this bond while sigma bond both a and p are formed.
- Sigma bond is rationally symmetrical around the internuclear axis while Pi bond is not rationally symmetrical.
Similarities between Sigma Bond and Pi Bond
- Both are a chemical covalent bond
- Both based on specific molecular orbitals
- Both are formed from the overlapping of particular atomic orbitals
- Both are either stable or unstable
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Comparison Video
Summary
The difference between sigma bond and Pi bond with the comparison chart highlighted in the article is worth reading. I hope the information written has answered the question. Use the comment section to share your views and suggestions.
More Sources and References
- Pi Bond. Wikipedia
- Sigma Bond and Pi Bond. Butane