The Noble gas Xenon (pronounced zee-non) has atomic number 54 and belongs in group 18, period 5 of the periodic table. A gas at room temperature xenon melts at 161.36 K (minus 111.79 C, minus 169.22 F) and boils at 165.03 K (minus 108.12 C, minus 162.62 F). This colorless gas has a density of 0.005887 grams per cubic centimeter at 237 K and an atomic weight of 131.293. As a noble gas, xenon has an oxidation state of zero. The ionization energy of the element is 12.130 eV.
While studying liquefied air in 1898, Sir William Ramsay and Morris M. Travers discovered xenon. This pair of scientists also discovered two other noble gases, neon and krypton in the same year. Its name comes from the Greek “xenon” meaning stranger. Extracting this gas from liquefied air is a testimony to their skill as the earth’s atmosphere contains only 0.0000087% xenon.
Today commercial manufacture of xenon still relies on the fractional distillation of liquid air. Xenon gas consists of single atoms of the element as apposed to gases such as oxygen, which consist of covalently bound pairs of atoms.
Xenon like all noble gases is remarkably stable. Noble gases owe this stability to their full outer shell of electrons. At one time, all noble gases were presumed totally inert and unable to form any compounds. This is no longer the case. Xenon forms over eighty compounds with fluorine, platinum and oxygen. One of these, xenon trioxide is highly explosive. While xenon itself is non-toxic, the highly oxidizing nature of its compounds makes them toxic. This oxidizing ability of perxenates is of use in analytical chemistry.
While normally found as a gas or in its liquid form at very low temperatures, if subjected to several hundred kilobars of pressure xenon forms a metal. This metal is unstable as release of the pressure results in the element resuming its gaseous phase.
All noble gases if subjected to an electric charge while contained in a vacuum tube emit a characteristic glow. In xenon’s case, this glow has a blue color. Such xenon-based vacuum tubes have use as antibacterial lamps. Other uses for xenon lights include stroboscopic effect lamps and exciting ruby lasers. Within nuclear energy studies, xenon’s high molecular weight makes it of use in equipment such as bubble chambers.
The highly successful experimental space probe Deep Space One, launched in 1998, used xenon ions as a fuel source in its novel ion propulsion engine.
Reference sources:
Los Alamos National Laboratory Chemistry Division
Web Elements
Jefferson Laboratories Science Education website
