In the context of the Hofmeister series , the anions I -, ClO - 4 , and SCN -have especially large binding constants to protein , which is historically associated with the definition of chaotropes or "structure breakers" , whereas Cl -binds more weakly . That said, NO - 3 is usually categorized as a structure-breaker on par with Br -in the Hofmeister series , and as weakly surface-active on the basis of VSFG measurements , yet the mean values of E CT that we obtain for NO - 3 are essentially identical in the bulk and interfacial environments, albeit with larger outliers in the interfacial case. The hypochlorite ion (ClO -) stands out in this analysis, with a significantly larger mean value of |E CT | in the interfacial environment. This species is not typically discussed in the context of the Hofmeister series or in VSFG studies of the air/water interface, due to its limited stability in aqueous solution.