Hybridization is the process of intermixing atomic orbitals in such a way as to form a new hybridized orbital. In simple words, hybridization is the preparation of an atom to make bonds. Similarly, sp3 hybridization is a process in which one s and three p atomic orbitals combine to create a set of four new sp3 hybrid orbitals. Each hybrid orbital consists of one large and a small lobe.
It is to be noted that the maximum electron density is concentrated in the big lobe. Therefore, the probability of finding the electron is negligible in the small lobe. Each Sp3 hybrid orbital has 25% s-character and 75% of p-character.
After hybridization, the four new sp3 hybrid orbitals combine in such a way as to give tetrahedral geometry. The equivalent hybrid orbitals are directed toward the four corners of the regular tetrahedrons.
For example, an sp3 hybridized orbital is shown here. Note that, for simplicity, the small lobes are not shown in geometry. The sp3 hybrid orbital arranges itself in such a manner the angle between them is 109.5°.
Stability of sp3 orbitals
On comparing the stabilities of the sp3, sp2, and sp hybrid orbitals, it is revealed that sp3 is the least stable. This is because the sp3 orbital has the least s-character which is closest to the nucleus and responsible for the stability. In addition to this, sp3 has a greater bond length than sp2 and sp hybrid orbitals.
Examples of sp3 hybridization
Sp3 hybridization of Methane (CH4)
In methane, the carbon atom is the central atom. It has two unpaired electrons in the ground state. During excitation, one electron of 2s is excited to the 2p orbital. The energy required for the excitation is satisfied by the energy released during hybridization.
All the bonds in methane are sigma bonds, which are formed by the head-to-head overlapping of hybrid orbitals of carbon and s orbital of hydrogen. The geometry of the methane molecule is tetrahedral and the bond angle is 109.5°.
Electronic configuration of the carbon:
6C= 1s22s22p1x2p1y2p0z
Sp3 hybridization of Ammonia (NH3)
In the ammonia molecule, nitrogen is the central atom. It has three unpaired electrons. One s and three p orbitals of nitrogen molecule form four new sp3 hybrid orbitals. One of the hybrid orbitals is completely filled whereas the other three hybrid orbitals are partially filled.
The nitrogen undergoes sp3-s overlap with hydrogen. So, the resulting shape of ammonia is a trigonal pyramid. In ammonia, three hydrogen atoms are present on the base, while the lone pair is present at the apex shown in the figure below:
The bond angle in ammonia is 107.5°. The deviation from the normal tetrahedral angle(109.5°) is due to repulsion between the bond pairs and lone pairs can be explained by VSEPR theory.
Hybridization of water (H2O)
In water, oxygen is the central atom. It has two unpaired electrons. However, out of the four hybrid orbitals, two are completely filled while the remaining two are half filled.
The oxygen undergoes sp3-s overlap. Hence, it forms two sigma bonds with hydrogen atoms. The two hydrogen atoms occupy two corners of the tetrahedron. Whereas the remaining is occupied by the lone pairs. The molecular geometry of water is bent or V-shape and the bond angle is 104.5°.
Related resources
- Molecular Geometry: A Complete Overview
- Wedge and Dash: The Ideal Model for Molecular Geometry
- Ball and Stick Model: A Convention
Concepts Berg
Among sp, sp2, and sp3, which hybrid orbital is more electronegative?
The ‘sp’ hybrid orbital is more electronegative than sp2 and sp3. This is due to the greater s character in the sp hybrid orbital. In the ‘sp’ hybrid orbital 50% s character and 50% p character is present and the s-orbital is closer to the nuclear than any other.
Why is the hybrid orbital during hybridization better than its parent atoms?
Hybrid orbitals are better than parent atomic orbitals in hybridization. This is because hybrid orbitals are more stable than parent atomic orbitals. They are formed by releasing the energy during mixing of atomic orbitals. However, they are also equivalent in energy and shape.
What is the percentage of s and p characters in sp, sp2, and sp3 hybrid orbital?
The s and p character in sp is 50% and 50% respectively. Whereas in sp2 s and p characters 33% and 67% respectively. In sp3 hybrid orbital s and p, the character is 25% and 75% respectively.
Explain sp3 Hybridization in Methane.
Methane is sp3 hybridized. It is formed by sp3-s overlapping of carbon and hydrogen respectively. It has tetrahedral geometry and the bond angle is 109.5°.
How does hybridization occur?
When atomic orbitals of different energy and shape intermix to form new hybrid orbitals of the same energy and shape, this process is known as hybridization.
Why do we need hybridization?
Hybridization is necessary to stabilize the electrons in their orbitals.
What is the difference between sp3 and sp2?
The sp3 hybridization is the combination of one s and three p orbitals. Whereas the sp2 hybridization is the combination of one s and two p orbitals. The geometry of sp3 hybridization is tetrahedral. and the bond angle is 109.5° whereas the geometry of the sp2 is trigonal planar and the bond angle is 120°.
Examples of sp3 hybridization?
There are the following compounds show sp3 hybridization:
- Methane
- Ammonia
- Water
- Tetrachloro phosphonium
References
- Inorganic chemistry by Catherine E. Housecroft and Alan G. Sharpe
- Chapter 2 (University of Calgary)
