In Chemistry, hybridization is the process of combining atomic orbitals into new hybrid orbitals (with shapes, and energy different than the original atomic orbitals) appropriate for the pairing of electrons to form chemical bonds in valence bond theory. To understand the hybridization of methane (CH₄), we have to examine the atomic orbitals of distinct shapes and energy that are included in the hybridization process. In this article, we will explain how the CH₄ Hybridization occurs in detail, CH₄ shapes, CH₄ bond angles, the formation of CH₄, etc.
What is Hybridization of Methane?
In general, CH₄ is a combination of 1 carbon and 4 hydrogen atoms. However, to form this bond the central atom which includes 4 valence electrons obtains more electrons from 4 hydrogen atoms to complete its octet. The formation of covalent bonds gets more precise when the electrons are shared between carbon and hydrogen.
Now, if we talk about the hybridization of methane, the central carbon is sp³ hybridized. It is because three 2p orbitals and one 2s orbital in the valence shell of carbon combine to form four sp³ hybrid orbitals of carbon to form C-H sigma bonds which eventually leads to the formation of methane molecules.
Formation of Methane (CH₄)
Methane is an organic compound and is the most important component of natural gas. The structure of methane includes a central carbon atom with four single bonds to form hydrogen atoms. To maximize the distance from each other, the four groups of bonding atoms do not fall on the same plane. Alternatively, each carbon atom lies at the corners of a geometrical shape known as tetrahedral. The carbon atom lies in the middle of the tetrahedron. Each face of the tetrahedron is an equilateral triangle in shape.
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The molecular geometry of methane is tetrahedral. The H-C-H bond angle of methane is 109.5 degrees and is greater than 90 degrees. While drawing the structural formula of methane, it is beneficial to represent the three-dimensional character of its shape. The structural formula of methane given below is a frame of reference. The dotted line bond is to be examined as moving back into the page while the solid triangle bond is to be examined as emerging out of the page.
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During the formation of sp³ orbitals, they arrange themselves in such a way that they are as far away as possible from each other. This is known as a tetrahedral arrangement with a bond angle of 109.5º.
No changes can be seen in terms of shape when the hydrogen atom combines with the carbon atom, and so the methane molecule takes the shape of a tetrahedral with a bond angle of 109.5º. Hence, the CH₄ structure is tetrahedral.
CH₄ Bond Angles
There are 4 pairs of outer electrons around the central atom in methane. These pairs of electrons repel each other.
The H-C-H bond angle in methane is the tetrahedral angle, 109.5º. The angle is formed when all the four pairs of outer electrons repel each other equally. The bond angles in ammonia and in water are less than 109.5º, due to the stronger repulsion by the lone pairs of electrons. Hence, the CH₄ bond angle is 109.5º.
Important Points to Note
Each sp³ hybrid orbital of carbon crossway 1s-orbital of hydrogen to form C-H sigma bonds.
The hybridization contains the combination of 1 s orbital and 3 p orbitals and there are no lone pairs.
The energy and shape of the sp³ hybrid orbitals are equal. They contain one unpaired electron each.
CH₄ Molecular Geometry and Bond Angles
Determining the CH₄ molecular geometry will be easier now as we have already discussed the bond formation and the process of hybridization above. In methane, the four hybrid orbitals are placed in such a way to minimize the force of repulsion between them. However, the four orbitals do repel each other and get disposed of at the corners of a tetrahedron. The shape of the CH₄ is tetrahedral. The sp³ hybrid orbital retains a bond angle of 109.5º.