Xenon
Xenon is a heavy, colorless noble gas present in only trace amounts in Earth's atmosphere, which made it one of the last of the naturally occurring noble gases to be found. Despite belonging to a group famous for barely reacting with anything, xenon was the first noble gas shown to form genuine chemical compounds, overturning what chemists had long assumed about the entire group.
- Group · Period
- 18 · 5
- At room temp
- gas
- Melts at
- 161.36 K
- Density
- 0.005887 g/cm³
- Discovered
- 1898
Uses
Xenon’s most visible use is in bright, natural-looking lighting: xenon arc lamps power some car headlights, movie theater projectors, and other high-intensity lighting where a crisp, daylight-like white light is wanted. Xenon flash lamps also produce the brief, powerful bursts of light used in some photographic flash units and strobe equipment.
Beyond lighting, xenon gas is used as a propellant in ion thrusters, where an electric field accelerates ionized xenon atoms out of a spacecraft to generate a gentle but highly efficient and long-lasting thrust, a technology that has powered several deep-space missions. Xenon also has genuine value as a medical anesthetic, producing fast, clean recovery, though its scarcity keeps it far more expensive than conventional anesthetic gases.
History
Xenon was discovered in 1898 by British chemists William Ramsay and Morris Travers, who had already identified neon and krypton that same year by carefully distilling liquid air into its component gases. After removing the other known gases, they were left with a tiny residue that turned out to be a previously unrecognized element, which they named xenon from the Greek word for “stranger,” reflecting how unexpected and unfamiliar the gas seemed. It remained a scientific curiosity for decades until practical uses in lighting, medicine and spaceflight gave it real industrial importance.
Fun facts
- Xenon is so rare in the atmosphere that it wasn't discovered until 1898, found in the leftover residue after separating other gases from liquid air.
- In 1962, xenon became the first noble gas ever shown to form a real chemical compound, upending the long-held belief that noble gases couldn't react at all.
- Xenon ion thrusters, which use electric fields to accelerate xenon ions for thrust, have powered several NASA and ESA deep-space missions.
Frequently asked questions
Can xenon really form chemical compounds if it's a noble gas?
Yes — xenon is the noble gas most willing to react, thanks to its relatively large, loosely held outer electrons. In 1962 chemist Neil Bartlett produced the first noble gas compound using xenon, and chemists have since made a range of xenon compounds with fluorine and oxygen, even though such reactions still require unusually strong reacting partners.
Why is xenon used in car headlights?
A xenon arc lamp produces an intensely bright, white light that closely resembles daylight when an electric current passes through xenon gas, which is why so-called xenon or HID headlights are prized for strong, natural-looking illumination. The same basic technology is used in movie projectors and other high-intensity lighting where brightness and color accuracy both matter.
Is xenon really used as an anesthetic gas?
It is — xenon has genuine anesthetic properties and produces rapid, clean recovery with few side effects, and it's been used in medical settings for this purpose. Its high cost relative to conventional anesthetics, driven by how rare and difficult to extract it is, has kept it from becoming a routine choice despite its advantages.
Compounds
4 notable compounds containing Xe
- XeF2halide
Xenon difluoride
A colorless crystalline solid and the simplest stable noble-gas compound, proof that xenon can form real chemical bonds despite its inert reputation.
Used for: Selective fluorinating and etching agent in semiconductor microfabrication
- XeF6halide
Xenon hexafluoride
The most reactive of the three well-characterized xenon fluorides, a colorless solid that reacts readily with trace moisture and even attacks glass.
Used for: Strong fluorinating agent in specialized inorganic synthesis
- XeF4halide
Xenon tetrafluoride
A colorless, square-planar crystalline solid and one of the first noble-gas compounds ever synthesized, formed by heating xenon and fluorine gas together under pressure.
Used for: Research reagent and strong fluorinating agent
- XeO3oxide
Xenon trioxide
A colorless, extremely explosive solid formed when xenon fluorides hydrolyze in water, a rare example of xenon bonded only to oxygen.
Used for: Laboratory curiosity illustrating xenon's higher oxidation states
Isotopes
43 known isotopes
Swipe to see all columns →
| Isotope | Natural abundance | Half-life | Decay mode | Mass excess | Binding energy / nucleon | Decay width |
|---|---|---|---|---|---|---|
| Xe-124 | 0.095% | 1.6E+14 Y | Double beta-plus decay | -87,667.41 keV | 8,437.61 keV | 9.04 × 10-38 eV |
| Xe-126 stable | 0.089% | Stable | — | -89,146.39 keV | 8,443.54 keV | — |
| Xe-128 stable | 1.91% | Stable | — | -89,860.53 keV | 8,443.3 keV | — |
| Xe-129 stable | 26.401% | Stable | — | -88,696.07 keV | 8,431.39 keV | — |
| Xe-130 stable | 4.071% | Stable | — | -89,880.47 keV | 8,437.73 keV | — |
| Xe-131 stable | 21.232% | Stable | — | -88,413.57 keV | 8,423.74 keV | — |
| Xe-132 stable | 26.909% | Stable | — | -89,278.97 keV | 8,427.62 keV | — |
| Xe-134 | 10.436% | 5.8E+22 Y | Double beta-minus decay (0%) | -88,125.83 keV | 8,413.7 keV | 2.49 × 10-46 eV |
| Xe-136 | 8.857% | 2.165E21 Y | Double beta-minus decay (100%) | -86,429.17 keV | 8,396.19 keV | 6.68 × 10-45 eV |
Show all 43 isotopes
| Xe-108 | — | 54 us | Alpha decay (100%), Two-proton emission | -42,632.36 keV | 8,074.89 keV | 8.45 × 10-12 eV |
| Xe-109 | — | 13 ms | Alpha decay (100%) | -46,169.55 keV | 8,107.31 keV | 3.51 × 10-14 eV |
| Xe-110 | — | 93 ms | Alpha decay (64%), Electron capture / beta-plus decay (36%), ECP | -51,922.64 keV | 8,159.28 keV | 4.91 × 10-15 eV |
| Xe-111 | — | 0.74 s | Alpha decay (8%), Electron capture / beta-plus decay | -54,520 keV | 8,182 keV | 6.17 × 10-16 eV |
| Xe-112 | — | 2.7 s | Electron capture / beta-plus decay (98.8%), Alpha decay (1.2%) | -60,026.35 keV | 8,230.06 keV | 1.69 × 10-16 eV |
| Xe-113 | — | 2.74 s | Electron capture / beta-plus decay (100%), ECP (7%), Alpha decay (0.011%) | -62,203.63 keV | 8,247.93 keV | 1.67 × 10-16 eV |
| Xe-114 | — | 10.0 s | Electron capture / beta-plus decay (100%) | -67,085.9 keV | 8,289.21 keV | 4.56 × 10-17 eV |
| Xe-115 | — | 18 s | Electron capture / beta-plus decay (100%), Beta-plus, proton emission (0.34%), Alpha decay (0.0003%) | -68,656.76 keV | 8,300.97 keV | 2.53 × 10-17 eV |
| Xe-116 | — | 59 s | Electron capture / beta-plus decay (100%) | -73,046.88 keV | 8,336.84 keV | 7.73 × 10-18 eV |
| Xe-117 | — | 61 s | Electron capture / beta-plus decay (100%), Beta-plus, proton emission (0.0029%) | -74,185.35 keV | 8,344.3 keV | 7.48 × 10-18 eV |
| Xe-118 | — | 3.8 m | Electron capture / beta-plus decay (100%) | -78,079.07 keV | 8,374.98 keV | 2.00 × 10-18 eV |
| Xe-119 | — | 5.8 m | Electron capture / beta-plus decay (100%) | -78,794.49 keV | 8,378.44 keV | 1.31 × 10-18 eV |
| Xe-120 | — | 40 m | Electron capture / beta-plus decay (100%) | -82,172.43 keV | 8,404.03 keV | 1.90 × 10-19 eV |
| Xe-121 | — | 40.1 m | Electron capture / beta-plus decay (100%) | -82,481 keV | 8,403.83 keV | 1.90 × 10-19 eV |
| Xe-122 | — | 20.1 h | Electron capture (100%) | -85,354.99 keV | 8,424.66 keV | 6.31 × 10-21 eV |
| Xe-123 | — | 2.050 h | Electron capture / beta-plus decay (100%) | -85,248.26 keV | 8,420.92 keV | 6.18 × 10-20 eV |
| Xe-125 | — | 16.9 h | Electron capture / beta-plus decay (100%) | -87,199.36 keV | 8,430.94 keV | 7.50 × 10-21 eV |
| Xe-127 | — | 36.346 d | Electron capture (100%) | -88,320.88 keV | 8,434.11 keV | 1.45 × 10-22 eV |
| Xe-133 | — | 5.2475 d | Beta-minus decay (100%) | -87,643.58 keV | 8,412.65 keV | 1.01 × 10-21 eV |
| Xe-135 | — | 9.14 h | Beta-minus decay (100%) | -86,413.37 keV | 8,398.48 keV | 1.39 × 10-20 eV |
| Xe-137 | — | 3.818 m | Beta-minus decay (100%) | -82,383.41 keV | 8,364.29 keV | 1.99 × 10-18 eV |
| Xe-138 | — | 14.14 m | Beta-minus decay (100%) | -79,972.24 keV | 8,344.69 keV | 5.38 × 10-19 eV |
| Xe-139 | — | 39.68 s | Beta-minus decay (100%) | -75,644.59 keV | 8,311.59 keV | 1.15 × 10-17 eV |
| Xe-140 | — | 13.60 s | Beta-minus decay (100%) | -72,986.46 keV | 8,290.89 keV | 3.35 × 10-17 eV |
| Xe-141 | — | 1.73 s | Beta-minus decay (100%), Beta-minus, neutron emission (0.044%) | -68,197.31 keV | 8,255.36 keV | 2.64 × 10-16 eV |
| Xe-142 | — | 1.23 s | Beta-minus decay (100%), Beta-minus, neutron emission (0.21%) | -65,229.65 keV | 8,233.17 keV | 3.71 × 10-16 eV |
| Xe-143 | — | 0.511 s | Beta-minus decay (100%), Beta-minus, neutron emission (0%) | -60,202.88 keV | 8,196.89 keV | 8.93 × 10-16 eV |
| Xe-144 | — | 1.15 s | Beta-minus decay (100%) | -56,872.3 keV | 8,172.88 keV | 3.97 × 10-16 eV |
| Xe-145 | — | 188 ms | Beta-minus decay (100%), Beta-minus, neutron emission (5%) | -51,493.34 keV | 8,135.09 keV | 2.43 × 10-15 eV |
| Xe-146 | — | 146 ms | Beta-minus decay (100%), Beta-minus, neutron emission (6.9%) | -47,954.95 keV | 8,110.42 keV | 3.12 × 10-15 eV |
| Xe-147 | — | 88 ms | Beta-minus decay (100%), Beta-minus, neutron emission (8%) | -42,400 keV | 8,072 keV | 5.18 × 10-15 eV |
| Xe-148 | — | 0.4 us | Beta-minus, neutron emission, Beta-minus decay | -38,650 keV | 8,047 keV | 1.14 × 10-9 eV |
| Xe-149 | — | — | Beta-minus decay (100%), Beta-minus, neutron emission, B-2N | -33,000 keV | 8,009 keV | — |
| Xe-150 | — | — | Beta-minus decay (100%), B-2N, Beta-minus, neutron emission | -28,990 keV | 7,983 keV | — |