Ion-ion and hydrogen-bonding interactions in solutions of 1-ethyl-3-methylimidazolium trifluoromethansulfonate ([C(2)mim]Tf) and triflic acid (HTf) are investigated with infrared and Raman spectroscopy. Bands indicative of highly aggregated triflate anions appear in the vibrational spectra of solutions containing a large fraction of triflic acid. These species most likely consist of triflate anions that ire at least threefold coordinated by positive ions (i.e., {[C(2)mim](x)HyTf}(x+y-1) where x + y >= 3). Such coordination environments would be consistent with a larp,er, extended aggregate of Tf-, [C(2)mim](+), and H+ ions that may be charged or neutral, Evidence for hydrogen bonding between the protons and the oxygen atoms of the triflate atoms and between the hydrogen atoms of the [C(2)mim](+) and triflate anion is identified in the infrared and Raman spectra.