Xenon (Xe)

Xenon is a chemical element with the atomic number 54 in the periodic table. It can be traced in Earth’s crust and mantle with an abundance of 30 parts per trillion (0.000000003%). Since element 54 is a gaseous substance that escapes easily into the atmosphere, larger quantities of this trace gas cannot remain in the layers of our planet.

Being a member of the noble gases family of periodic table elements, this colorless and odorless element has eight valence electrons in its outer shell. This makes xenon an extremely stable and inert gas. It’s most popular application is in flash lamps, but also has a significant role in medicine for various diagnostic uses and in anti-cancer therapy. 

Chemical and Physical Properties of Xenon

Symbol of XenonXe
Atomic Number of Xenon54
Group of XenonNoble Gas
Crystal Structure of XenonCubic: Face centered
Atomic Weight of Xenon131.29
Shells of Xenon2,8,18,18,8
Orbitals of Xenon[Kr] 4d10 5s2 5p6
Valence of Xenon0
Electro Negativity of Xenon0
Covalent Radius of Xenon1.31 Å
Atomic Radius of Xenon1.24 Å
Atomic Volume of Xenon37.3 cm³/mol
Name Origin of XenonGreek: xenos (strange).
Discovered BySir William Ramsay; M. W. Travers
Pronounced of XenonZEE-non
Oxydation States of Xenon0
Density of Xenon0.00588 g/cm³
Uses of XenonUsed for filling flash lamps and other powerful lamps. Electrical excitation of xenon produces a burst of brilliant white light. Also used in bubble chambers and modern nuclear power reactors.
Description of XenonVery soft, light gray, ductile metal.
Physical stateGas at room temperature
Half-lifeFrom 32(10) milliseconds to 1.8(0.5 (stat), 0.1 (sys))×1022 years
Electronegativity according to PaulingUnknown
Most characteristic isotope132Xe
The energy of the first ionization1170 kJ.mol-1
The energy of the second ionizationN/A

With the periodic table symbol Xe, atomic number 54, atomic mass of 131.29 g.mol-1, and electron configuration [Kr] 4d105s25p6, xenon is a colourless, odorless, and tasteless gas with a face-centered cubic structure. Xenon reaches its boiling point at −108.099°C, −162.578°F, 165.051 K, while the melting point is reached at −111.75°C, −169.15°F, 161.4 K.

As a member of the noble gases family of elements, xenon has an unknown electronegativity according to Pauling, whereas the atomic radius according to van der Waals is 0.217 nm. This chemically unreactive (inert) gas emits blue blue light when exposed to release and transmission of electricity in an applied electric field. At 155 GPa, xenon gas turns into a metallic substance.                  

How Was Xenon Discovered?

While working at the University College London, UK, the Scottish chemist Sir William Ramsay (1852-1916) and Morris Travers were trying to answer a question posed by Henry Cavendish a century ago. Namely, the research they conducted in 1894 was focused on investigating why nitrogen extracted from chemical compounds is about one-half percent lighter than the nitrogen extracted from the air. 

Sir Ramsey observed that when he triggers a chemical reaction between hot magnesium metal and atmospheric nitrogen, the residue contains a heavier and even less reactive gas. Ramsey and Travers found the Greek word ‘argon’ as the most suitable depiction of this ‘lazy’ and inert gas. Since there was no predicted slot in Mendeleev’s system for this type of substance, the two scientists were convinced that they’re on the verge of discovering a completely new family of elements – the noble gas group.

The only caveat was that the argon had higher boiling point than the missing element. So, Ramsey and Travers tried to examine a sample of some argon-krypton residues with a spectroscope. This method of analysis displayed previously unseen beautiful blue lines. With no doubt whatsoever, the two chemists were now certain of the presence of a new strange element, labeled as xenon. 

How Did Xenon Get Its Name?

The name of this chemical element originates from the Greek word ‘xenos‘, meaning ‘stranger’. Element’s 54 name was suggested by its discoverer, Sir William Ramsay.

Where Can You Find Xenon?

Xenon can be found in the entire Universe. It occurs in meteors, comets, and asteroids. This noble gas can be traced in Earth’s atmosphere as a mixture with other noble gases and oxygen. The air we breathe contains around 0.00000087% of this gaseous chemical element. Some mineral springs also release xenon gas. For commercial purposes, xenon is obtained by extraction from liquid air.

Xenon in Everyday Life

Although it’s a rare and inert gas, xenon has several significant practical uses:

  • Xenon-135 isotope is highly significant for the operation of nuclear fission reactors;
  • Element 54 is used in stroboscopic lights due to its ability to produce brilliant white flash of light when it is excited electrically;
  • Applied in specialised light sources, xenon emits a beautiful blue glow when excited by an electrical discharge. 
  • The aforementioned chemical property of element 54 is especially valued in photography, manufacturing of sunbed lamps, photographic flashes, high-intensity arc-lamps for motion picture projection, high-pressure arc, deep-sea observation lamps, bubble chambers, as well as in the xenon lamps that are used in food preparation and processing;
  • Ultraviolet lights which are used in the bactericidal lamps to sterilize laboratory equipment also contain some xenon quantity;
  • Xenon ion propulsion systems keep the satellites in orbit;
  • In medicine, xenon difluoride is used for making of 5-fluorouracil – a drug administered in anti-cancer treatments;
  • Radioisotopes of this chemical element are used in imaging technologies such as tomography and gamma emission to image major organs such as the brain, lungs, and heart;
  • By measuring the xenon-129 content of meteorites we can learn more about the early days of our Solar system.

How Dangerous Is Xenon?

Xenon gas is a simple asphyxiant. Despite the fact that elemental xenon is non-toxic, the oxidizing property of this chemical element makes xenon compounds highly dangerous and toxic substances. 

Since this chemical has no smell, color, nor taste, it’s easy for people that work with xenon to be unknowingly exposed to high concentrations of the gas. In such cases, dizziness, nausea, vomiting, loss of consciousness, or even death may occur. However, xenon is not classified as a carcinogen substance. 

In addition, xenon oxides (especially xenon trioxide (XeO3) and xenon tetroxide (XeO4)) are highly explosive and toxic oxidizing agents. 

Environmental Effects of Xenon

Since the pure form of element 54 is a chemically non-reactive gas, it’s effects on the environment cannot be considered. 

On the other hand, xenon-135 isotope is commonly used in nuclear reactors. It has an ability to absorb 4,000 more neutrons than uranium. In case of a nuclear catastrophe or improperly disposed waste, xenon may become an environmental pollutant but with no long term consequences. 

Isotopes of Xenon

There are 40 isotopes of xenon. Among them, nine are stable: 124Xe, 126Xe, 128Xe, 129Xe, 130Xe, 131Xe, 132Xe, 134Xe, and 136Xe. Having a half life of 2.165 ± 0.016(stat) ± 0.059(sys) ×1021 years, the xenon-136 isotope is counted toward the longest measured half-lives of all nuclides. After tin, xenon is the second element with the largest number of stable isotopes.

Isotopes of xenon undergo several decay modes: alpha decay, beta decay, double electron capture and the predicted double beta decay mode to isotopes of Te, I, Sb, Cs, and Ba. Furthermore, xenon has 32 artificial unstable isotopes. With a half life of 36.345 days, xenon-127 is the longest living unstable form of this chemical element.

Main isotopes of xenon

Iso­tope Decay abun­dance half-life (t1/2) mode pro­duct 124Xe 0.095% 1.8×1022 y[1] εε 124Te 125Xe syn 16.9 h ε 125I 126Xe 0.089% stable 127Xe syn 36.345 d ε 127I 128Xe 1.910% stable 129Xe 26.401% stable 130Xe 4.071% stable 131Xe 21.232% stable 132Xe 26.909% stable 133Xe syn 5.247 d β− 133Cs 134Xe 10.436% stable 135Xe syn 9.14 h β− 135Cs 136Xe 8.857% 2.165×1021 y[2] β−β− 136Ba Source: Wikipedia

List of Xenon Compounds 

Xenon has a stable electron configuration with 8 valence electrons in its outer shell. This makes element 54 unreactive to other chemicals, for which it is labeled as an inert gas. When it participates in a compound, xenon typically exhibits the oxidation states + 1/2, +2, +4, +6, and +8. 

Despite belonging to the group of inert gases, xenon is the first noble gas found to form compounds with other elements. This was observed in 1962, by the English chemist Neil Bartlett (1932–2008) who is credited for making the first noble gas compounds by forming a compound consisting of xenon, fluoride, and platinum.

By bonding to other chemical elements (mostly with fluorine, oxygen and platinum), xenon is able to form organoxenon compounds, xenates, oxides, chlorides, and fluorides:


  • Bis(pentafluorophenyl)xenon
  • Monosodium xenate
  • Nitrosonium octafluoroxenate(VI)
  • Perxenate
  • Tetramethylammonium pentafluoroxenate
  • Tetraxenonogold(II)
  • Xenic acid
  • Xenon dichloride
  • Xenon difluoride
  • Xenon dioxide
  • Xenon fluoride nitrate
  • Xenon hexafluoride
  • Xenon hexafluoroplatinate
  • Xenon hexafluororhodate
  • Xenon monochloride
  • Xenon nitrate
  • Xenon oxydifluoride
  • Xenon oxytetrafluoride
  • Xenon tetrachloride
  • Xenon tetrafluoride
  • Xenon tetroxide
  • Xenon trioxide

5 Interesting Facts and Explanations

  1. According to the chemical calculations, there are 0.000008% (0.08 parts per million) of xenon in the atmosphere of planet Mars. 
  2. American engineer Harold Edgerton began exploring strobe light technology during the 1930s for high speed photography. This led him to the invention of the xenon flash lamp
  3. All noble gases classified in the Group XVIII of the periodic table are chemically inert substances. This group includes elements such as neon, argon, krypton, helium, xenon, and radon.
  4. Xenon was not the only scientific discovery of Sir William Ramsay. Namely, he also succeeded in discovering (or co-discovering) the noble gases helium, argon, neon, and krypton.
  5. Sir William Ramsay was awarded the Nobel Prize for Chemistry in 1904. The motivation for awarding the most prestigious scientific acknowledgment to this Scottish scientist was his discovery of the inert gaseous elements in air, as well as determining their properties and classification in the periodic table.