The boundary films generated oil a series of inorganic compounds, typical of native films oil metal and ceramic surfaces, when exposed to various ionic liquids (ILs) based oil the trihexyl(teti-adecyl)phosphonium cation have been characterized using multinuclear solid-state NMR. The NMR results indicate that SiO2 and Mg(OH)(2) interact strongly with the anion and cation of each IL through a mechanism of adsorption of the anion and subsequent close proximity of the cation in a surface double layer as observed through H-1-Si-29 cross polarization experiments). In contrast, Al2O3, MgO, ZnO, and ZrO2 appear less active, strongly suggesting the necessity of hydroxylated surface groups ill order to enhance the generation of these interfacial films. Using solid-state NMR to characterize Such interfaces not only has the potential to elucidate mechanisms of wear resistance and corrosion protection via iLs, but is also likely to allow their rapid screening for such durability applications.