Question

What is the bond angle of the molecule undergoing ${\mathrm{sp}}^2$hybridization?

Answer 1

Bond angle:

• It is defined as the angle between the orbitals containing bonding electron pairs around the central atom in a molecule or complex ion.
• The bond angle is measured in degrees.
• It can be obtained experimentally using spectroscopic methods.

Hybridization:

• When an atom undergoes mixing and recasting of two atomic orbitals with almost the same energy levels to form new orbitals of equal number with equivalent energy, maximum symmetry, and a fixed orientation in space is known as hybridization.

${\mathrm{sp}}^2$ hybridization:

• When an atom undergoes mixing and recasting of one s and two p orbitals with similar energies to form three new ${\mathrm{sp}}^2$hybrid orbitals with equivalent energies, maximum symmetry, and fixed orientation in space is called ${\mathrm{sp}}^2$ hybridization.

The bond angle of ${\mathrm{sp}}^2$ hybridization:

• The molecules forming ${\mathrm{sp}}^2$hybridization have a bond angle of ${120}^{°}$and the geometry is trigonal planar.
• The repulsion between the bond pair and lone pair of electrons causes the atoms to be at the maximum distance apart causing the bond angle of ${120}^{°}$.
• A mixture of $\mathrm{s}\&\mathrm{p}$ orbitals formed in trigonal symmetry maintains the angle at ${120}^{°}$
• All the three hybrid orbitals remain in one plane and make an angle of ${120}^{°}$ with one another. Each of the hybrid orbitals formed has a $33.33\%\mathrm{s}$ character and $66.66\%\mathrm{p}$ character.
• Example: In boron trichloride ${\mathrm{BCl}}_3$ undergoes ${\mathrm{sp}}^2$hybridization where there are three sigma bonds with ${120}^{°}$bond angle and trigonal planar geometry.