Cyanogen

Cyanogen was a gas that was poisonous to humans and some other species. However, a few species needed it for survival, in particular the Celegians. Other species, such as Trandoshans, Weequay, and Sullustans were immune to its toxic effects.

It was an important factor in the defeat of Naga Sadow's Massassi forces on Kirrek during the Great Hyperspace War. The Celegian Jedi Master Ooroo sacrificed himself by tipping his chamber filled with cyanogen into the Massassi and, as it shattered, it killed many warriors. He was subsequently poisoned by oxygen.

Around 3951 BBY the Jekk'Jekk Tarr Cantina on Nar Shaddaa was oriented towards clientele from species that could breathe the gas, and circulated cyanogen as a deterrent against humans entering the bar. The bounty hunter Mira was able to enter using an enviro-suit that she had stolen from Meetra Surik. This forced Surik to enter without protection to rescue Mira. She was temporarily subdued by the gas but overcame it due to her Jedi training and Force abilities.

Cyanogen was a constituent of cyanogen silicate.