Cyanogen gas released from Ooroo's tank during the Battle of Kirrek Cyanogen is a poisonous gas to humans and a number of other species. Conversely, certain species, notably the Celegians, required it to live. Trandoshans, Weequay, and Sullustans, among others, possessed immunity to its harmful effects.
During the Great Hyperspace War, it played a crucial role in the defeat of Naga Sadow's Massassi forces on Kirrek. The Celegian Jedi Master Ooroo made the ultimate sacrifice, releasing cyanogen from his chamber onto the Massassi. The chamber shattered, resulting in the deaths of many warriors. Tragically, Ooroo himself was subsequently poisoned by oxygen.
Around 3951 BBY, the Jekk'Jekk Tarr Cantina located on Nar Shaddaa catered to species capable of breathing the gas and used cyanogen as a deterrent to keep humans out of the establishment. The bounty hunter Mira managed to gain entry by using an enviro-suit she had previously stolen from Meetra Surik. This compelled Surik to enter without protection to save Mira. Although temporarily overcome by the gas, she overcame its effects due to her Jedi training and abilities in the Force.
Cyanogen silicate contains cyanogen as a component.