This page contains information regarding Star Trek: Strange New Worlds, and thus may contain spoilers.
Trilithium resin was a highly toxic waste product that was produced by the engines of Starfleet vessels in the 24th century. It could be produced from trilithium, and might simply be called that. A volatile substance, its only possible use was as a weapon. Storing and moving it was a very delicate process and required specialized equipment. (TNG: "Starship Mine"; DS9: "For the Uniform")
In 2259, Captain Christopher Pike claimed to the Shepherds that, should they refuse to accept the USS Enterprise's surrender and it were destroyed, the trilithium resin in the starship's warp core would ignite and destroy the comet C/2260-Quentin that the Shepherds venerated. (SNW: "Children of the Comet")
In 2369, a group of weapons dealers led by Kelsey attempted to steal trilithium resin for later sale to terrorists from the warp core of the USS Enterprise-D while it was undergoing a baryon sweep at Arkaria Base. They were stopped by Captain Jean-Luc Picard. (TNG: "Starship Mine")
Trilithium resin was also had the effect of rendering a planet uninhabitable to Humans (but not Cardassians) when dispersed through the planet's atmosphere by a quantum torpedo detonation. Four hundred kilograms of trilithium used in this manner was enough to make a planet uninhabitable to Humans for fifty years. Captain Benjamin Sisko poisoned the atmosphere of Solosos III with trilithium resin in 2373 in response to Michael Eddington's use of cobalt diselenide, a biogenic weapon. (DS9: "For the Uniform")