|
|
Atomic Number: |
54 |
Melting Point: | -111.79 ºC | |
| Atomic Symbol: | Xe | Boiling Point: | -108.12 ºC | ||
| Atomic Weight: | 131.30 amu | Density: | 10490
kg/m 3 |
||
| Atomic Radius: |
218 pm |
Oxidation States: | -- | ||
| Covalent Radius: | 153 pm | Electron Configuration: | [Kr]5s24d105p6 | ||
| van der Waals Radius: |
172 pm |
State of Matter: | solid |
(Gr. xenon, stranger) Discovered in 1898 by Ramsay and Travers in residue left after evaporating liquid air.
A colorless, very heavy, odorless noble gas, xenon occurs in the earth's atmosphere in trace amounts and was part of the first noble gas compound synthesized. Xenon is a member of the zero-valence elements that are called noble or inert gases. The word "inert" is no longer used to describe this chemical series since some zero valence elements do form compounds. In a gas filled tube, xenon emits a blue glow when the gas is excited by electrical discharge. Using several hundred kilobars of pressure, metallic xenon has been made. Xenon can also form clathrates with water when its atoms are trapped in a lattice of the water molecules.
Before 1962, xenon and the other noble gases were generally considered to be chemically inert and not able to form compounds. Evidence since this time has been mounting that xenon, along with other noble gases, do in fact form compounds. Some of the xenon compounds are; difluoride, hexafluoride, sodium perxenate, tetrafluoride, xenon deuterate, xenon hydrate. The highly explosive compound xenon trioxide has also been made. There are at least 80 xenon compounds in which fluorine or oxygen are bonded to xenon. Some compounds of xenon are colored but most are colorless.
It is present in the atmosphere to the extent of about one part in twenty million. Xenon is present in the Martian atmosphere to the extent of 0.08 ppm. The element is found in the gases evolved from certain mineral springs, and is commercially obtained by extraction from liquid air.
The gas is used in making electron tubes, stoboscopic lamps, bactericidal lamps, and lamps used to excite ruby lasers that generate coherent light. Xenon is used in the nuclear energy field in bubble chambers, probes, and other applications where a high molecular weight is of value. The perxenates are used in analytical chemistry as oxidizing agents. 133Xe and 135Xe are produced by neutron irradiation in air cooled nuclear reactors. 133Xe has useful applications as a radioisotope. The element is available in sealed glass containers of gas at standard pressure.
Natural xenon is composed of nine stable isotopes. In addition to these, 20 unstable isotopes have been characterized.
Xenon is not toxic, but its compounds are highly toxic because of their strong oxidizing characteristics.
