SP Hybridisation

The hybridisation of orbitals was first introduced to explain the phenomenon of molecular structure. Before hybridisation, molecular structures were explained using the valence bond theory until they could not predict them correctly. The valence bond theory explained that the local bonds formed between two atoms due to losing electrons from each atom.

The VSEPR theory predicts the shape of a molecule, and the hybrid orbital theory explains how the shapes are achieved. sp hybridisation is formed when one atomic orbital of s and p combines to form an equivalent orbital. This type of hybridisation is also known as diagonal hybridisation and is seen in compounds like BeCl2. 

What is sp Hybridisation?

In chemistry, orbital hybridisations mix atomic orbitals to create new hybrid orbitals suitable for pairing electrons to form atomic orbitals. For example, in a carbon atom forming four single bonds, the valence shell orbitals combine with the p-orbitals of the three valence shells to form four equivalent sp3 mixtures around the carbon, with four different atoms combined to hybrid orbitals are symmetrically placed in space to help explain the molecular structure and atomic bond properties. Hybrid orbitals are usually formed by mixing atomic orbitals of equivalent energy.

Sp hybrids are observed when s and p orbitals mix within the same main shell of an atom to form two new equivalent orbitals. The newly formed orbital is called the sp hybrid orbital. It forms a linear molecule at an angle of 180 degrees. This hybrid type involves mixing equal energy “s” and “p” orbitals to give a new hybrid, the sp hybrid orbital. They are also called diagonal hybridisation. Each new sp hybrid orbital formed has the same amount of character of s and p, that is fifty per cent each.

Let’s look at the BeCl2 (beryllium dichloride) hybrid; here, Be is the central atom. The electronic configuration of Be is 1s2,2s2; the electronic configuration shows that there are two electrons in the valence or the outer shell.

In the formation of BeCl2, the beryllium atom will bond with the two chlorine atoms available via a concurrent single bond. There are two electron pairs around the central atom. No lone pair of electrons are available in the molecule. Analysing this information, we can say that BeCl2 exhibits sp hybridisation.

Another example of sp hybridisation is acetylene. Acetylene is also written as C2H2.

Here, looking at the electron configuration of carbon in the ground state, it is expressed as 1s2, 2s2, 2p2. One of the electrons moves or jumps from the 2s orbital to the 2pz orbital in the excited state. The electron configuration changes to 1s2 2s12px12py12pz1. On the other hand, since the CH molecule has only one hydrogen atom, the 2s1 orbital and the 2pz1 orbital are hybrid orbitals. It further leads to forming a 4sp hybrid orbital, with each CH molecule forming a 2sp hybrid orbital.

In the hybrid orbital, CC sigma bonds are formed when the sp orbitals of each carbon overlap and two CH bonds are formed when the second sp orbital of each carbon overlaps the 1s orbital of hydrogen. A carbon atom has two half-filled 2p orbitals; these pairs of p-orbitals do not play any role in hybrid orbitals formation but instead form a pair of pi bonds to form a triple bond.

Types of Hybridisation

Hybridisation is the product of two or many orbitals together. Before discussing the types of hybridisation, let’s discuss how many types of orbitals are known in chemistry. There are seven different types of orbitals observed in a molecule. They are s orbital, p orbital, d orbital, f orbital, g orbital and h orbital. Out of these seven orbitals, only four orbitals, namely; s, p, d and f, occupy the ground state of an atom. Therefore these four mentioned orbitals are of utmost importance, and we will discuss them.

The s orbital and the p orbital can create three hybridisation types: sp, sp2 and sp3. The sp hybridisation gives a linear shape to the molecule; the sp2 hybridisation will give a planer trigonal shape, while the sp3 type gives a tetrahedral shape to the molecule.

sp, sp2 and sp3 are the most important hybridizations studied in chemistry. If you search for types of hybridisation examples, most of the examples will be from these three types. One of the most studied examples of hybridisation is the BeCl2 hybridisation to form a linear shape or sp hybridisation.

Importance of Hybridisation

The concept of hybridisation is the opposite of what the electron always wants to achieve; that is, lower energy states and stability. However, the hybrid allows the molecule to have a shape that minimises energy. This bond also releases energy (dissociation) by stabilising itself. In other words, the formation of bonds tends to occur. Hybridisation is important to maintain the shape of the molecules during the movement of electrons from a lower orbit to a higher orbit. If the concept of hybridisation were not there, the resulting molecules would have distorted shapes that their native shape.

Conclusion

The hybridisation of orbitals is an important event to maintain the shape of a molecule when its energy is changing. Hybridisation is important because it allows the molecule to have a shape that minimises energy. It lowers the energy and creates a stable bond that helps maintain the molecule’s shape. sp hybridisation is a hybrid of s and p orbitals.

Here the hybrid orbital formed has a fifty percent character of s and fifty percent character of p. C2H2, and BeCl2 are the two well-known examples of sp hybridisation. Sp hybridisation and types of hybridisation notes will help you clear your concept of hybridisation type and importance.