The HA/L pairs studied are those tested in this study, HCl/FeCl3, HBr/FeBr3, CF3COOH/FeCl3, as well as HF/BF3 (Table ). It should be noted that for the binary mineral acids studied, the HA-L is not stable relative to the separated HA and L species and so the energy calculated from equation 5 corresponds with the complexation energy between A -and L.