Main Difference

When two atoms come in interaction with each other, they form a chemical bond between them by which they are held together. So, in the field of chemistry, a thing that is used to tie or anchor things together is called the chemical bond. Chemical bonds are classified into some types, which are: Ionic bond, Covalent bond, Polar bond, and Hydrogen bond. Here, we are going to discuss sigma bond and pi bond which are the types of covalent bond. Sigma bonds (σ bonds) are the strongest type of chemical bond (covalent bond) which are formed by overlapping of the head between orbits of the atom, whereas pi bonds (π bonds) are the weaker type of chemical bond (covalent bond) as compared to the sigma bonds (σ bonds). It is formed when two lobes of one orbit overlap two lobes of the second orbit involved.

Comparison Chart

What is Sigma Bond?

Sigma bond is also written as σ bond because symbol σ is a Greek letter used for sigma. Sigma bonds (σ bonds) are one of a type of covalent bonding of atom. It is the strongest type of covalent bond formed between two atoms. It is formed when the head of atomic orbital’s overlaps with each other along the internuclear axis of the atoms. The relativity of the compound formed is inversely proportional to some sigma bonds (σ bonds), whereas the stability of the compound is directly proportional to the number of sigma bonds (σ bonds). This bond decides the shape of the molecule, the overlapping at the internuclear axis allows the molecule to rotate around its axis which gives it a rotational symmetry. Sigma bonds (σ bonds) can be formed by an orbit as well as p orbit. The interesting thing is that a single bond contains only one sigma bonds (σ bonds), whereas multiple bonds like double bond and triple bond also contain only one sigma bonds (σ bonds). Examples of sigma bonds (σ bonds) are ammonia (NH3) and benzene ring etc.

What is Pi Bond?

A Pi Bond is also written as π bond because symbol π is Greek letter used for pi. Pi bonds (π bonds) are one of a type of covalent bonding in an atom. It is a weaker type of covalent bond as compared to sigma bonds (σ bonds). Pi Bond are formed by the overlapping of atomic orbital’s sidewise. Following that there is a partial overlapping due to which pi bond (π bond) becomes weaker as compared to the other bonds. The relativity of the compound formed is directly proportional to some pi bonds (π bonds) whereas the stability of the compound is inversely proportional to the number of pi bonds (π bonds). This shorter bond decides the length of the molecule. The orbital overlapping is perpendicular to the internuclear axis of the atom which does not allow any rotation in the atom, which means that this bond has a non-rotational symmetry. Pi bond (π bond) is formed only by p orbital. The interesting thing is that a single bond contains only one pi bond (π bond), whereas multiple bonds like double bond have two pi bonds (π bonds) and triple bond has three pi bonds (π bonds). Examples of pi bonds (π bond) are dicarbon (C2) and diborane (B2H2).

Sigma Bond vs. Pi Bond

• Sigma bond (σ bond) is the strongest type of covalent bond formed between two atoms, whereas pi bond (πbond) is a weaker type of covalent bond as compared to sigma bonds (σ bonds).
• Sigma bond (σ bond) is formed when the head of atomic orbitals overlaps with each other along the internuclear axis of the atoms while Pi bond(π bond) is formed by the overlapping of atomic orbitals.
• Sigma bond (σ bond) decides the shape of molecule whereas pi bond (πbond) decide the length of the molecule.
• Sigma bond (σ bond) can rotate around the internuclear axis while pi bond (πbond) cannot rotate around an internuclear.
• In sigma bond (σ bond), the relativity of the compound formed is inversely proportional to some sigma bonds (σ bonds) whereas the stability of the compound is directly proportional to the number of sigma bonds (σ bonds). While contrary to this in a pi bond (πbond), the relativity of the compound formed is directly proportional to some pi bonds (π bonds) whereas the stability of the compound is inversely proportional to the number of pi bonds (π bonds).
• In the case of sigma bond (σ bond), a single bond contains only one sigma bonds (σ bonds), following that multiple bonds like double bond and triple bond also contain only one sigma bonds (σ bonds). On the other hand, in the case of the pi bond (πbond), a single bond contains only one pi bond (π bond), whereas multiple bonds like double bond have two pi bonds (π bonds) and triple bond has three pi bonds (π bonds).