Hybrid orbitals form on the central atom and can either be sp, sp2, sp3, sp3d, or sp3d2.
The type of hybrid orbitals that are used is dictated by the electron domain geometry.
Sigma bonds are formed by the end-to-end overlap of bonding orbitals. Pi bonds are formed by the side-to-side overlap of p orbitals.
Oxygen is sp3 hybridized. It forms 2 bonds with chlorine and has two lone pair of electrons present. Hence, a total of 4 hybrid orbitals are required.
In sp³ hybridization, one s orbital and three p orbitals hybridize to form four sp³ orbitals, each consisting of 25% s character and 75% p character. This type of hybridization is required whenever an atom is surrounded by four groups of electrons.
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