 Ionic liquids, IELs, are molten salts that have been shown to provide excellent protection against wear and friction reduction in lubricant applications. Researchers have demonstrated that certain IEL compounds can also be used as added as a non-polar base oils, maintaining the same level of performance as the neat IEL. These IELs contain large asymmetric ions, which adhere to metal surfaces and form a protective layer under boundary lubrication conditions. In addition, certain IEL compounds can also react to form a protective tribofilm when fluorine, phosphorus or boron atoms are present in the constituent ions. This article was authored by Anthony E. Summers, Patrick C. Howlett, Douglas R. McFarlane and others.