Xenon
Element 54 · Noble Gas
Xenon is a heavy, colorless noble gas with a full outer shell that made chemists believe for decades that it could never form compounds — until 1962, when xenon tetrafluoride proved them wrong and opened noble-gas chemistry. Excited xenon emits an intensely bright white-blue light, which is why xenon arc lamps illuminate cinemas, lighthouses, and car headlights. It is also one of the few gases used as a general anesthetic, prized for its fast onset and minimal side effects, and its high atomic mass makes it the ideal propellant for ion thrusters that push deep-space probes across the solar system.
Key facts
| Atomic number | 54 |
|---|---|
| Atomic weight | 131.29 |
| Category | Noble Gas |
| Group / Period | 18 / 5 |
| Block | p |
| Electron configuration | [Kr] 4d10 5s2 5p6 |
| Common oxidation states | 0, +2, +4, +6 |
| State at STP | Gas |
| Electronegativity | 2.6 |
| Atomic radius | 108 pm (covalent) |
| Density | 5.894 g/L (gas at STP) |
| Melting point | -111.75 °C |
| Boiling point | -108.04 °C |
Occurrence
Xenon is a trace component of air, present at only about 0.09 parts per million. It is obtained by fractional distillation of liquefied air, alongside the other noble gases.
Applications
High-intensity arc lamps and headlights
General anesthesia
Ion thrusters for deep-space probes
Medical imaging research
Common compounds
- Xenon difluoride
- Xenon tetrafluoride
- Xenon trioxide
Xenon was long thought completely inert, but in 1962 chemists made the first true noble-gas compound — xenon tetrafluoride — rewriting the textbooks.
Data source: IUPAC standard atomic weights 2021; NIST physical property data