- Butyllithium may refer to one of three isomeric organolithium reagents used in chemical synthesis: n-Butyllithium, sec-Butyllithium, tert-Butyllithium.
- n-Butyllithium (abbreviated n-BuLi) is an organolithium reagent. It is widely used as a polymerization initiator in the production of elastomers such as polybutadiene or styrene-butadiene-styrene (SBS).
- Butyllithium is commercially available as solutions (15%, 25%, 2 M, 2.5 M, 10 M, etc.) in alkanes such as pentane, hexanes, and heptanes. Solutions in diethyl ether and THF can be prepared, but are not stable enough for storage.