Tantalum bi-lithium thalo-dihydroxide, also known as TLTDH gas, was a chemical that became a colorless, odorless, non-flammable gas at 1 ATM and temperatures within Human norm. Composed of molecules of tantalum, lithium, hydrogen and oxygen, TLTDH was an early anaesthetic amongst the Vulcan and Romulan civilizations. A noted effect was the production of laughter amongst them after exposure to the gas as well as feelings of exhilaration, euphoria and sometimes unconsciousness, somehow the way nitrous oxide affects humans.