In chemistry, hybridization is defined as the process of combining two atomic orbitals to create a new type of hybridised orbitals. The formation of hybrid orbitals with completely different energies, shapes, and so on is frequently the outcome of this intermixing. Hybridization is mostly carried out by atomic orbitals of the same energy level. Fully filled and half-filled orbitals, however, can both participate in this process if their energies are equivalent.
What is Hybridization?
Hybridization is the idea that atomic orbitals combine to form newly hybridised orbitals which will in turn influence molecular geometry and bonding properties. We can say that hybridization is also an expansion of the valence bond theory. In order to explore this idea further we will utilise three types of hydrocarbon compounds to illustrate sp3, sp2, and sp hybridization.
Characteristics of Hybridization
Some of the following characteristics of Hybridization is give below-:
1.Hybridization occurs when orbitals belonging to the same atom or ion have similar energies.
2.The number of hybrid orbitals equals the number of orbitals involved in the hybridization process.
3.In terms of energy and shape, hybrid orbitals are always comparable.
4.In comparison to pure atom orbitals, hybrid orbitals generate more stable bonds.
5.The goal of hybridization is to create equivalent orbitals that have the most symmetry.
6.It is unknown whether or not hybridization actually occurs. It’s a theory that describes how molecules behave in the real world.
7.The hybrid orbitals are directed in space in the same desired direction in order to have a stable arrangement and provide the molecule a proper shape.
Types Of Hybridization
The types of hybridization are as follows:
1) (sp) Hybridisation
In sp hybridization one s- and one p-orbital are combined together to generate two sp – hybrid orbitals with a linear structure and a bond angle of 180 degrees.
Each sp hybridised orbital has the same proportion of s and p characters – 50 percent s character and 50 percent p character.
For example, when BeCl2 is formed, the first atom is in the excited state 2s12p1, which is then hybridised to generate two sp – hybrid orbitals. BeCl2is formed when these hybrid orbitals collide with the two p-orbitals of two chlorine atoms.
2) (sp2) Hybridisation
One s- and one p-orbital are combined together to generate three sp2– hybrid orbitals with a triangular planar shape and a bond angle of 120 degrees.These three hybrid orbitals remain in the same plane and form a 120° angle with one another. The hybrid orbitals have a 33.3 percent ‘s’ character and a 66.66 percent ‘p’ character in each of them.
A triangle planar form is found in all the molecules through which the central atom is connected to three other atoms and is sp2 hybridised
3) (sp3) Hybridisation
One s- and three p-orbitals are merged in this hybridization to generate four sp3– hybrid orbitals with a tetrahedral structure.These are aimed at the four corners of a conventional tetrahedron and form a 109°28′ angle with each other.
The sp3 hybrid orbitals have a 109.280 degree angle between them.
Each sp3 hybrid orbital contains 25% s character and 75% p character.
Ethane and methane are two examples of sp3 hybridization.
The inter mixing of 1s, 3p, and 1d orbitals to generate 5 sp3d hybridised orbitals of equal energy is known as sp3d hybridization. Their geometry is trigonal bipyramidal.
The trigonal bipyramidal symmetry is formed by combining the s, p, and d orbitals.
The equatorial orbitals are three hybrid orbitals in the horizontal plane that are inclined at a 120° angle to each other.
The remaining two orbitals, known as axial orbitals, are located in the vertical plane at 90 degrees to the equatorial orbitals.
Hybridization in Phosphorus Pentachloride as an example (PCl5).
5) sp3d2 Hybridization
The 1s, 3p, and 2d orbitals of sp3d hybridization are intermixed to generate six identical sp3d2 hybrid orbitals.
These six orbitals are aimed at the octahedron’s corners.
They are angled at a 90-degree angle to one another.
Hybridization explains not just atom-to-atom bonding, but also molecular shapes. Hybridization is the process of mixing (hybridising) two or more separate pure atomic orbitals of the same energy level to produce two or more identical hybrid atomic orbitals.
Hybridization is regarded as a powerful evolutionary force because it can result in following
(1) increased intraspecific genetic diversity among participating populations
(2) the emergence of new species
(3) the extinction of species due to genetic assimilation