Xenon

After William Ramsay and Morris Travers successfully collected neon, argon, and krypton from liquid air in 1898, they wondered if other gases were in the atmosphere. One day, they received a high-tech gift from wealthy businessman Ludwig Mond—a new liquid-air machine that was able to collect larger amounts of Krypton. After repeating the process several times, they eventually collected a heavier gas that glowed a beautiful blue color when isolated in a vacuum tube. This gas did not react during their experiments, so they concluded that they had found another member of the inert gas group and named it xenon after the Greek word xénos, meaning 'foreign(er)', 'strange(r)', or 'guest'.

As decades passed, scientists continued to study xenon, all contributing to our modern understanding of the noble gas. In the 1930s, Harold Edgerton studied the light created by sending electricity through xenon gas. From1939 to 1951, Albert R. Behnke Jr., Nikolay V. Lazarev, and John H. Lawrence, investigated the anesthetic properties of xenon. In 1962, Neil Bartlett was able to combine xenon and hexafluoride and created the first known compound. Most recently, in the 1980s, IBM scientists used new technology to position xenon atoms on chilled crystal nickel, marking the first time atoms were purposefully positioned on a flat surface.

Though xenon can form some compounds, it is mostly nonreactive and therefore considered inert and a member of the noble gas group. Xenon is about 4.5 times denser than the Earth's atmosphere at sea level. It absorbs red light when metallized, turning a bright sky-blue color, and it turns lavender when combined with electricity.

Because xenon can emit a bright blue color, it is useful in some light sources like high-speed light bulbs used for photography, tanning beds, lamps used for food preparation and processing, and lamps used in ruby lasers. It can also be used to keep satellites and some spaceships in orbit by accelerating the high-mass ions. For example, NASA's Xenon Ion Drive engine fires a small number of xenon ions at high speed (146,000 km/hour for the Deep Space 1 probe). In addition, xenon is used in when producing 5-fluorouracil, a drug used to treat certain types of cancer. Finally, xenon is used as an oxidizing agent in nuclear energy fields.

Before 1962, most scientists assumed xenon was unable to form compounds like most other noble gases. In recent years, new discoveries have shown that xenon, as well as other members of zero valance elements, do form compounds. Among the compounds of xenon now reported are sodium perxenate, xenon deuterate, xenon hydrate, difluoride, tetrafluoride, and hexafluoride. Xenon trioxide, which is highly explosive, is another compound that has been achieved.

Xenon can also combine with fluorine to create three fluorides (XeF₂, XeF₄, and XeF₆), oxygen to create three oxides (XeO₃, XeO₄, and XeO₂), and other less electronegative compounds like carbon. 

Natural xenon is composed of nine stable isotopes. In addition to these, 20 unstable isotopes have been characterized.

Xenon is available in very small amounts in Earth’s atmosphere. Like other noble gases, it is obtained through evaporating liquid air, but can also be found in the gas emitted by mineral springs.

Xenon can also be found in space—though limited on Earth, the Sun, and some asteroids, it is found in large quantities on Jupiter. It is also formed during supernova explosions.

Finally, nuclear fission produces some stable and long-lived isotopes of xenon.