The pH-dependent structures of the 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) self-assembled monolayers (SAMs) on the silver surface were studied by surface enhanced Raman scattering (SERS) spectroscopy. The resulting SERS spectra show that the adsorption fashion of AMT monolayers formed at pH 1 could exhibit the strongest interaction with the silver surface among the investigated pH values at 1, 7, and 13. Electrochemical impedance spectroscopy (EIS) illuminates that the anticorrosive effect of AMT monolayers formed under pH 1 is the best. The inhibition efficiencies of AMT SAMs formed under pH 1, 7 and 13 are 72.2, 39.1 and 4.97%, respectively, according to experimental results of their Tafel plots. (C) 2008 Elsevier B.V. All rights reserved.