Types of Hybridization

Hybridization can be classified as sp³, sp², sp, sp³d, sp³d², or sp³d³ based on the types of orbitals involved in mixing.

sp Hybridization

It occurs when one s and one p orbital in an atom’s main shell combine to form two new equivalent orbitals. The newly formed orbitals are known as sp hybridized orbitals. It produces linear molecules at a 180° angle. It entails combining one’s orbital and one ‘p’ orbital of equal energy to produce a new hybrid orbital known as an sp hybridized orbital. 

• It’s also known as diagonal hybridization. 
• Each sp hybridized orbital contains the same amount of s and p characters. 
• All beryllium compounds, such as BeF₂, BeH₂, and BeCl₂, are examples.

sp² Hybridization

It occurs when one s and two p orbitals of the same atom’s shell combine to form three equivalent orbitals. The newly formed orbitals are known as sp² hybrid orbitals. It’s also known as trigonal hybridization. It entails combining one’s orbital with two ‘p’ orbitals of equal energy to create a new hybrid orbital known as sp². A trigonal symmetry mixture of s and p orbitals is kept at 120 degrees. All three hybrid orbitals remain in the same plane and form a 120° angle with one another. 

• Each hybrid orbital formed has a 33.33 % and a 66.66 % ‘p’ character. 
• The molecules with a triangular planar shape have a central atom that is linked to three other atoms and is sp² hybridized. Boron compounds are examples.

sp³ Hybridization

When one ‘s’ orbital and three ‘p’ orbitals from the same shell of an atom combine to form four new equivalent orbitals, the hybridization is known as tetrahedral hybridization or sp³. The newly formed orbitals are known as sp³ hybrid orbitals. These are pointed at the four corners of a regular tetrahedron and form a 109°28′ angle with one another. 

• The sp³ hybrid orbitals form a 109.28-degree angle. 
• Each hybrid orbital has a 25% s character and a 75% p character. 
• Ethane and methane are two examples.

sp³d Hybridization

The mixing of 1s orbitals, 3p orbitals, and 1d orbitals results in 5 sp3d hybridized orbitals of equal energy. Their geometry is trigonal bipyramidal. The combination of s, p, and d orbitals results in trigonal bipyramidal symmetry. The equatorial orbitals are three hybrid orbitals that are oriented at a 120° angle to each other and lie in the horizontal plane. 

• The remaining two orbitals, known as axial orbitals, are in the vertical plane at 90 degrees plane of the equatorial orbitals. 
• Hybridization in Phosphorus Pentachloride, for example (PCl₅).

sp³d² Hybridization

When 1s, 3p, and 2d orbitals combine to form 6 identical sp³d² hybrid orbitals, the hybridization is called sp³d² Hybridization. These seven orbitals point to the corners of an octahedron. They are inclined at a 90-degree angle to one another.

sp³d³ Hybridization

It has 1s, 3p, and 3d orbitals, which combine to form 7 identical sp³d³ hybrid orbitals. These seven orbitals point to the corners of a pentagonal bipyramidal. e.g. IF₆.

The concept of hybridization is defined as the process of combining two atomic orbitals to create a new type of hybridized orbitals. This intermixing typically results in the formation of hybrid orbitals with completely different energies, shapes, and so on. Hybridization is primarily carried out by atomic orbitals of the same energy level. However, both fully filled and half-filled orbitals can participate in this process if their energies are equal. The concept of hybridization is an extension of valence bond theory that helps us understand bond formation, bond energies, and bond lengths.