Krypton, neon, and xenon are rare atmospheric gases.
Each is odorless, colorless, tasteless, nontoxic, monatomic, and chemically inert. All three together constitute less than 0.002 percent of the atmosphere, with approximately concentration in atmosphere of 18 ppm for neon, 1.1 ppm for krypton, and 0.09 ppm for xenon.
Neon, Krypton, and xenon are used principally to fill lamp bulb and tubes. The electronic industries uses them singly or in mixture in many types of gas-filled electron tubes (among them, voltage regulator tubes, starter tubes, phototubes, counter tube, T.R. Tubes, xenon thyratron tubes, half wave xenon rectifier tube and Geiger Muller tubes. Large quantities of neon (as well as a atmospheric helium and specially purified argon) are employed as fill gases in illuminated signs. Small quantities of Krypton and Xenon are used for effects.
In the lamp industry, the three gases serve as fill gas in specialty lamps, neon glow lamps, 100-watt fluorescent lamps, ultraviolet sterilizing lamps, and very high output lamps. The three gases have additional applications in the atomic energy field as fill gas for ionization chambers, bubble chamber, gaseous scintillation counters, and other detection and measurement devices