In general, the infrared (IR) spectra of phthalate-containing ZN catalysts exhibit a broad ν(C=O) band around 1700 cm -1 . In the literature, 5 curve fitting resulted in five peaks, three of which, centered at 1707, 1680 and 1657 cm -1 , were assigned to phthalate coordinating with MgCl2 in different modes: Chelating on {110} overlapped with monodentate on {100}, monodentate on {110}, and chelating at defects, respectively. Given the dominance of chelate adsorption observed in Figure , we conducted a vibrational analysis on one of the most stable structures, to verify if it could explain the experimental spectrum. The band was found to be broad, though not as much as the experimental one, likely because the simulated spectrum was obtained from only one nanoplate (Figure ). However, the most crucial observation was the variation in the wavenumber of the C=O stretching vibration within the same chelate adsorption mode, ranging from 1705 to 1671 cm -1 . Subsequently, we performed a Hirshfeld charge analysis on the Mg 2+ cations binding to DEP in the chelate mode, after removing DEP molecules from the same nanoplate. The results revealed variations in the charge of Mg 2+ cations, reflecting differences in the local environment, where the positivity (acidity) and wavenumber were inversely correlated (Figure ). Based on these findings, we propose that the broad band observed in the experimental IR spectra of phthalate-containing ZN catalysts is not necessarily an indication of different adsorption modes, rather it could be the consequence of the charge of Mg 2+ cations binding to the ID being sensitive to the local environment and varying even when coordination and adsorption remain the same. bridging the edges and concavities. Such motifs were rarely seen in the absence of IDs.