Summary of typical FTIR peaks for diclofenac sodium are  around 3000–3100 cm⁻¹ is C-H stretch (aromatic), around 1600 cm⁻¹ is C=C stretch (aromatic), around 3300–3400 cm⁻¹ is N-H stretch (amine group), around 1700–1725 cm⁻¹ is C=O stretch (carboxylate group), around 1200–1300 cm⁻¹ is C-N stretch (amine), around 700–800 cm⁻¹ is C-Cl bending vibrations (chlorophenyl) and  around 1200–1400 cm⁻¹ is sodium ion interaction (if salt form is present).