Zeiton-7

Zeiton-7 was a rare fuel which was used by TARDISes. It was used to generate orbital energy, which allowed the ship to move. It could be also used for fuel by other space-time vessels. It was generally found on Varos, though Galatron Mining Corporation had also found traces of Zeiton-7 on an asteroid. (DW: Vengeance on Varos) The Eighth Doctor once suggested it could be synthesised — perhaps using compressed nitrogen as a base —but the exact formula eluded him. (BFA: The Creed of the Kromon) Zeiton-7 could also be used to form part of a cold fusion generator. (NA: Lucifer Rising) Frying them along with other steps would blow up the TARDIS, but if done when a blackhole is about to open, saves the universe and the TARDIS. (DW: Time Crash)