Periodic Table


Atomic number: 54
Atomic weight: 131.29
Symbol: Xe
Group number: 18
Electronic configuration: [Kr].4d10.5s2.5p6


Xenon is a "noble" or "inert" gas present in the atmosphere to a small extent. Xenon is present in the Martian atmosphere to the extent of about 0.08 ppm. Before 1962, it was generally assumed that xenon and other noble gases were unable to form compounds. Among the compounds of xenon now reported are xenon hydrate, sodium perxenate, xenon deuterate, difluoride, tetrafluoride, hexafluoride, and XePtF6 and XeRhF6. The highly explosive xenon trioxide, XeO3, is known.

Metallic xenon is produced by applying several hundred kilobars of pressure. Xenon in a vacuum tube produces a blue glow when excited by an electrical discharge and finds use in strobe lamps. It is an odourless, colourless, inert gas.

General information

Discoveror: Sir William Ramsay, Morris W. Travers
Date discovered: 1898
Discovered at: England
Meaning of name: From the Greek word "xenos" meaning "stranger"

Physical data

Standard state: gas at 298 K
Colour: colourless
Density of solid at ambient temperature/kg m-3: no data
Molar volume/cm3: 35.92

Radii /pm

Atomic: 108
Covalent (single bond):
Pauling radius for the ion [Xe]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius90.7102.739.5no data


Both values are quoted on the Pauling scale.

Pauling: 2.60
Allred Rochow: 2.40

Crystal Structure

structure: ccp (cubic close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.


Temperatures (/K)

melting point: 161.4
boiling point: 161.4

Enthalpies /kJ mol-1

fusion: 2.30
vaporization: 12.6

single bond enthalpies:
Xe-F Xe-Cl Xe-Br Xe-I Xe-Xe
126 no data no data no data 6.53

Ionization enthalpies /kJ mol-1

Number Enthalpy


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
124Xe123.9058942 (22)0.10 (1)
126Xe125.904281 (8)0.09 (1)
128Xe127.9035312 (17)1.91 (3)
129Xe128.9047801 (21)26.4 (6)
130Xe129.9035094 (17)4.1 (1)
131Xe130.905072 (5)21.2 (4)
132Xe131.904144 (5)26.9 (5)
134Xe133.905395 (8)10.4 (2)
136Xe135.907214 (8)8.9 (1)

Further Information

Copyright 1997 Mark Winter
Department of Chemistry at the University of Sheffield, Sheffield S3 7HF, England.

The current version of this document is at http://www.shef.ac.uk/~chem/web-elements-I/Xe.html