Xenon gas purity 99,999%
Atomic number 54
Molecular weight 131,293 g/mol
Group number 18
Group name Rare gases
CAS registry ID 7440-63-3
UN number UN 2036
History & Occurrence
Xenon (from the Greek word ξένος, meaning “strange”) was discovered in England by William Ramsay and Morris Travers on July 12, 1898, shortly after they had discovered the elements krypton and neon. They found it in the residue left over from evaporating components of liquid air.
Xenon is a trace gas in the Earth’s atmosphere, occurring in one part in twenty million. In addition, it is found in gases emitted from some mineral springs.
This element can be extracted by fractional distillation of liquid air or by selective adsorption (surface binding) on activated carbon. The isotopes Xe-133 and Xe-135 are synthesized by neutron irradiation within air-cooled nuclear reactors.
Xenon is most widely used in light-emitting devices called xenon flash lamps (for flash photography), stroboscopic lamps, to excite the active medium in lasers, in bactericidal lamps (occasionally), and in certain dermatological uses.
Certain xenon arc lamps are used in solar simulators, some projection systems, automotive high-intensity discharge (HID) lamp headlights, and other specialized devices. They are an excellent source of short-wavelength ultraviolet light, and they have intense emissions in the near infrared, which are used in some night vision systems.
Xenon has been used as a general anesthetic, but the cost is extremely high.
In nuclear energy applications, it is used in bubble chambers, probes, and in other areas where a high-molecular-weight, inert substance is needed.
Xenon salts called perxenates are used as oxidizing agents in analytical chemistry.
The isotope 129Xe is used for hyperpolarized MRI of the lungs and other tissues.
It is the preferred fuel for ion propulsion, because of its high molecular weight, ease of ionization, storability as a liquid near room temperature (but at high pressure), and easy convertibility back into a gas to fuel the engine. Its inert nature makes it environmentally friendly and less corrosive to an ion engine than other fuels such as mercury or cesium. Europe’s SMART-1 spacecraft utilized xenon in its engines.
It is commonly used to analyze protein structures by crystallography. Xenon atoms can be bound to protein molecules in a crystal, creating a high quality, heavy-atom derivative that is then analyzed.