What is the Difference Between Sigma and pi Bonds?

The main difference between sigma and pi bonds lies in the way atomic orbitals of two atoms overlap during the formation of these bonds. Here are the key differences between sigma and pi bonds:

1. Formation: Sigma bonds are formed by the linear or co-axial overlapping of atomic orbitals, while pi bonds are formed by the parallel or lateral overlapping of atomic orbitals.
2. Strength: Sigma bonds are generally stronger than pi bonds due to the direct head-to-head overlap between orbitals.
3. Independence: Sigma bonds can exist independently in single bonds, while pi bonds must coexist with a sigma bond and are only found in double and triple bonds.
4. Charge Symmetry: Sigma bonds have cylindrical charge symmetry around the axis of the bond, while pi bonds have no symmetry.
5. Reactivity: Atoms with sigma bonds are less reactive, while atoms with pi bonds are highly reactive compared to those with only sigma bonds.
6. Molecule Shape: Sigma bonds can be used to determine the shapes of molecules, while pi bonds cannot be used for the same purpose.

In summary, sigma bonds are formed by the linear or co-axial overlapping of atomic orbitals and are stronger than pi bonds, which are formed by the parallel or lateral overlapping of atomic orbitals. Sigma bonds can exist independently, while pi bonds must coexist with a sigma bond. Sigma bonds have cylindrical charge symmetry, while pi bonds have no symmetry. Atoms with sigma bonds are less reactive than atoms with pi bonds, and sigma bonds can be used to determine molecule shapes, while pi bonds cannot.

Comparative Table: Sigma vs pi Bonds

Here is a table comparing the differences between sigma and pi bonds:

In summary, sigma bonds are stronger and can exist independently in single bonds, while pi bonds are weaker and must coexist with a sigma bond in double and triple bonds. Sigma bonds have cylindrical charge symmetry, while pi bonds lack symmetry. Atoms with sigma bonds are less reactive than atoms with pi bonds.