weakly coordinating anions. Both cationic and anionic components have been widely varied. Cations Room-temperature ionic liquids (RTILs) are dominated by salts derived from 1-methylimidazole, i.e., 1-alkyl-3-methylimidazolium. Examples include 1-ethyl-3-methyl- (EMIM), 1-butyl-3-methyl- (BMIM), 1-octyl-3 methyl (OMIM), 1-decyl-3-methyl-(DMIM), 1-dodecyl-3-methyl- docecylMIM). Other imidazolium cations are 1-butyl-2,3-dimethylimidazolium (BMMIM or DBMIM) and 1,3-di(N,N-dimethylaminoethyl)-2-methylimidazolium (DAMI). Other N-heterocyclic cations are derived from pyridine: 4-methyl-N-butyl-pyridinium (MBPy) and N-octylpyridinium (C8Py). Conventional quaternary ammonium cations also form ILs, e.g. tetraethylammonium (TEA) and tetrabutylammonium (TBA). Anions Typical anions in ionic liquids include the following: tetrafluoroborate (BF4), hexafluorophosphate (PF6), bis-trifluoromethanesulfonimide (NTf2), trifluoromethanesulfonate (OTf), dicyanamide (N(CN)2), hydrogen sulphate (HSO4), and ethyl sulphate (EtOSO3). Magnetic ionic liquids can be synthesized by incorporating paramagnetic anions, illustrated by 1-butyl-3-methylimidazolium tetrachloroferrate. Specialized IL's Protic ionic liquids are formed via a proton transfer from an acid to a base. In contrast to other ionic liquids, which generally are formed through a sequence of synthesis steps, protic ionic liquids can be created more easily by simply mixing the acid and base. Phosphonium cations (R4P+) are less common but offer some advantageous properties. Some examples of phosphonium cations are trihexyl(tetradecyl)phosphonium (P6,6,6,14) and tributyl(tetradecyl)phosphonium (P4,4,4,14). Poly(ionic liquid)s Polymerized ionic liquids, poly(ionic liquid)s or polymeric ionic liquids, all abbreviated as PIL is the polymeric form of ionic liquids. They have half of the ionicity of ionic liquids since one ion is fixed as the polymer moiety to form a polymeric chain. PILs have a similar range of applications, comparable with those of ionic liquids but the polymer architecture provides a better chance for controlling the ionic conductivity. They have extended the applications of ionic liquids for designing smart materials or solid electrolytes. Commercial applications Many applications have been considered, but few have been commercialized. ILs are used in the production of gasoline by catalyzing alkylation. An IL based on tetraalkylphosphonium iodide is a solvent for tributyltin iodide, which functions as a catalyst to rearrange the monoepoxide of butadiene. This process was commercialized as a route to 2,5-dihydrofuran, but later discontinued. Potential applications Catalysis ILs improve the catalytic performance of palladium nanoparticles. Furthermore, ionic liquids can be used pre-catalysts for chemical transformations. In this regard dialkylimidazoliums such as [EMIM]Ac have been used in the combination with a base to generate N-heterocyclic carbenes (NHCs). These imidazolium based NHCs are known to catalyse a number transformations such as the Benzoin condensation and the OTHO reaction. Pharmaceuticals Recognizing that approximately 50% of commercial pharmaceuticals are salts,