Liquid hydrogen
Liquid hydrogen was the liquid form of hydrogen.

Pursued by Captain James T. Kirk and Lieutenant Commander Spock in 1968, Gary Seven fled his apartment via transporter and appeared inside a liquid hydrogen assembly area in the McKinley Rocket Base. ()

During Wesley Crusher's psych test on Relva VII in 2364, one of the technicians told Crusher that the liquid hydrogen was going to blow. The shutoff valve ruptured and would blow the environmental maintenance lab. ()

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Chemical compounds