IR for Esters: The strong carbonyl (C=O) stretching vibration in esters typically appears in the region of 1735-1750 cm-1. This band is characteristic of esters and can be used to differentiate them from other functional groups. Additionally, the presence of an ester group can be confirmed by the appearance of a strong band in the region of 1200-1300 cm-1, which is attributed to the C-O stretching vibration.
