Tantalum bi-lithium thalo-dihydroxide

Tantalum Bi-Lithium Thalo-Dihydroxide, also known as TLTDH gas, was a chemical that became a colorless, odorless, non-flammeable gas at 1 ATM and temperatures within Human norm. It was an early anaesthetic amongst the Vulcan's and Romulan species. A noted effect was the production of laughter amongst them after exposure to the gas as well as feelings of exhiliration, euphoria and sometimes unconsciousness.

In the post industrial but pre space flight era, a social problem emerged when crude TLTDH became popular to "cook up" from non-conductive Tantalo-Lithial compounds that were commonly used as electrical insulation.

In the 2260's, it was sythesized by the crew of the USS Enterprise in order to cure the accidental infection of Spock and Romulans at the ARK-7 facility by the Oroborus virus. The effects of the virus knocked out the Romulan invaders that had boarded the starbase.