The key difference between hybridization and overlapping is that hybridization refers to the formation of new hybrid orbitals via overlapping of atomic orbitals, whereas overlapping refers to the mixing of atomic orbitals.
Orbitals are hypothetical structures that can be filled with electrons. According to different discoveries, scientists proposed different shapes for these orbitals. There are three main types of orbitals: atomic orbitals, molecular orbitals, and hybrid orbitals. Hybrid orbitals form via the process of hybridization. Hybridization and overlapping are two related chemical concepts. Overlapping of atomic orbitals occurs during hybridization.
CONTENTS
1. Overview and Key Difference
2. What is Hybridization
3. What is Overlapping
4. Side by Side Comparison – Hybridization vs Overlapping in Tabular Form
5. Summary
What is Hybridization?
Hybridization is a chemical process in which hybrid orbitals form from the mixing of atomic orbitals. Hybridization theory is a technique we use to describe the orbital structure of a molecule. Basically, hybridization is the formation of hybrid orbitals by mixing two or more atomic orbitals. The orientation of these orbitals determines the geometry of the molecule. It is an expansion of the valence bond theory.
Before the formation of the atomic orbitals, they have different energies, but after the formation, all orbitals have the same energy. For example, an s atomic orbital, and a p atomic orbital can combine to form two sp orbitals. The s and p atomic orbitals have different energies (energy of s < energy of p). But, after hybridization, it forms two sp orbitals which have the same energy, and this energy lies between the energies of individual s and p atomic orbital energies. Moreover, this sp hybrid orbital has 50% s orbital characteristics and 50% p orbital characteristics.
Figure 01: Formation of Hybrid Orbitals
The idea of hybridization first came into the discussion because since the valence bond theory failed to correctly predict the structure of some molecules such as CH4. Although the carbon atom in CH4 has only two unpaired electrons according to its electron configuration, it can form four covalent bonds. To form four bonds, there must be four unpaired electrons.
The only way to explain this phenomenon was to think that s and p orbitals of carbon atom fuse with each other to form new orbitals called hybrid orbitals which have the same energy. Here, one s + three p gives 4 sp3 orbitals. Therefore, the electrons fill these hybrid orbitals evenly (one electron per hybrid orbital), obeying the Hund’s rule. Thus, there are four electrons for the formation of four covalent bonds with four hydrogen atoms.
What is Overlapping?
Overlapping is the chemical process in which atomic orbitals overlap with each other. In other words, it is the concentration of orbitals in the space between different atoms, which leads to the formation of chemical bonds. Linus Pauling first developed the theory about this orbital overlapping. He explained the molecular bond angles in different molecules, and this concept was the basis for hybridization theory.
What is the Difference Between Hybridization and Overlapping?
Hybridization and overlapping are two related chemical concepts. The key difference between hybridization and overlapping is that hybridization is the formation of new hybrid orbitals via overlapping of atomic orbitals, whereas overlapping is the mixing of atomic orbitals. Furthermore, in hybridization process, orbitals of the same atoms overlap to form hybrid orbitals while in overlapping process, the orbitals of the same atom overlap to form hybrid orbitals and orbitals of different atoms overlap to form chemical bonds.
The below infographic presents more facts on the difference between hybridization and overlapping.
Summary – Hybridization vs Overlapping
Hybridization and overlapping are two related chemical concepts. In summary, the key difference between hybridization and overlapping is that hybridization refers to the formation of new hybrid orbitals via overlapping of atomic orbitals, whereas overlapping means the mixing of atomic orbitals.
Reference:
1. Helmenstine, Anne Marie. “Hybrid Orbital Definition.” ThoughtCo, Jun. 22, 2018, Available here.
Image Courtesy:
1. “Sp hybridization” By Tem5psu – Own work (CC BY-SA 3.0) via Commons Wikimedia