For the chemical compound, please see argonite.
Argon is a chemical element, number 18 on the periodic table.
The lifeform named Sluggo, taken aboard Enterprise NX-01 in 2151, came from a planet with an argon-rich atmosphere. To help him survive aboard the ship, an argon lamp was positioned close to Sluggo. (ENT: "Fight or Flight")
In 2267, the Galileo crash landed on Taurus II. The crew found the atmosphere breathable, an oxygen-nitrogen mixture, with traces of argon, neon, and krypton, not dissimilar to that of Earth. (TOS: "The Galileo Seven")
The same year, the atmosphere of Gamma Canaris N also was determined to be oxygen-nitrogen, with traces of krypton, argon and neon. (TOS: "Metamorphosis")
The Azure Nebula, a class 11 nebula, was composed primarily of oxygen and argon, with other compounds. (VOY: "Flashback")
Larger quantities of argon were found in atmospheres of class H planets or moons. (VOY: "Scorpion, Part II") Class L planets also had high quantities of argon in their atmospheres. (VOY: "The 37's")
The destruction of the Caretaker's array in 2371 left vapor composed of hydrogen, helium, mercury, and argon. (VOY: "The Voyager Conspiracy")
The planet Ahmedeen had seas of liquid argon. (VOY: "Course: Oblivion")
A class T nebula encountered by the USS Voyager in 2376 was composed of hydrogen, helium, and argon. (VOY: "Tinker Tenor Doctor Spy")