Answer:
sp^3
Explanation:
In valence bond theory, orbital hybridization around a central atom with a bond angle of less than 109.5° typically indicates sp³ hybridization. This hybridization involves the mixing of one s orbital and three p orbitals, resulting in four sp³ hybrid orbitals.
However, if the bond angle is slightly less than 109.5°, it is usually due to the presence of lone pairs of electrons on the central atom. These lone pairs exert greater repulsive forces compared to bonding pairs, thereby compressing the bond angles slightly below the ideal tetrahedral angle of 109.5°. A common example is the water molecule (H₂O), where the bond angle is approximately 104.5° due to the two lone pairs on the oxygen atom.
So, in summary, for a bond angle of less than 109.5°, the orbital hybridization around the central atom is typically sp³.
