Molybdenum disulfide is one of the best known solid lubricants. The chemical substance gained notice by aerospace and military applications, bt nowadays it is found in a variety of tribological systems. It is widely used as an additive for greases and assembly pastes, in fluid lubricants like industrial gear oils, in dry solid film lubricants including bonded coatings.

Molybdenum disulfide exists in two crystalline forms, hexagonal and rhombohedral. The hexagonal form is by far the most common and being the only type found in commercial ores. Also, the hexagonal form has been found in synthetic MoS2.