reaction (1) in Scheme 2) via phosphonate groups. This process results in the loss of surface hydroxyl groups (≡Mn-OH) due to ligand-exchange reactions. IS complexes are identified by the appearance of IR frequencies in the phosphonate region (1200 -900 cm -1 ; ν(PO)). As illustrated in Figure , the phosphonate groups of glyphosate can form various IS complex configurations, including mononuclear monodentate (MM), mononuclear bidentate (MB), and binuclear bidentate (BB). Peak assignments and fitting for the various P-O-Mn configurations are detailed in Figure and Table . The relative absorbance of P-O-Mn vibrational modes indicates that pH and protein associations influence the type of IS configuration glyphosate forms or prefers (Figures and). At pH 4.6, the simultaneous disappearance of the ν(POH) band at 917 cm⁻¹ and the emergence of peaks at ~980 and ~930 cm⁻¹ signify the development of bidentate BB and MB coordination modes, respectively (Table and Figure ). Additionally, the appearance of a phosphonate stretching vibrational mode at ~1109 cm -1 , along with the ν(P=O) band at ~1130 cm -1 , indicates the formation of an MM configuration (Figure ). This MM configuration more likely occur in the presence of BSA association at pH 4.6 and under both BSA-associated and non-associated conditions at pH 7.2. Overall, these results indicate weaker retention and a higher likelihood of glyphosate release from BSA-Mn oxide surfaces.