What is Xenon's atomic number?

Xenon has atomic number 54, meaning it has 54 protons in its nucleus. Its chemical symbol is Xe, from the Greek xenos, meaning stranger or foreign.

Is Xenon truly unreactive?

Xenon is far less reactive than most elements, but it is not completely inert. In 1962, Neil Bartlett synthesized xenon hexafluoroplatinate (Xe+[PtF6]−), the first noble gas compound, disproving the "inert gas" label. Xenon forms stable fluorides (XeF2, XeF4, XeF6) and oxides under special conditions.

What is Xenon used for?

Major uses include high-intensity arc lamps for cinema projectors and vehicle headlights (HID/xenon lamps), deep-ultraviolet light sources for semiconductor chip lithography, general anesthetic in medicine (at ~63% inspired concentration), radioactive Xe-133 as a pulmonary ventilation tracer in nuclear medicine pulmonary ventilation scintigraphy (SPECT/planar gamma camera), and xenon ion propellant in spacecraft thrusters (e.g., NASA's Dawn and ESA's Bepi-Colombo missions).

What is Xenon's electron configuration?

Xenon's electron configuration is [Kr] 4d10 5s2 5p6. The full 5p subshell (6 electrons) gives it an exceptionally stable closed-shell structure and very high first ionization energy of 1170.4 kJ/mol. Its shells are 2, 8, 18, 18, 8.

Who discovered Xenon?

Xenon was discovered in 1898 by Scottish chemist Sir William Ramsay and English chemist Morris Travers at University College London. They isolated it from residues left after evaporating liquid air components, only days after discovering krypton by the same technique.

How abundant is Xenon on Earth?

Xenon is extremely rare in the atmosphere at about 87 parts per billion by volume (0.0000087%). It is obtained commercially by fractional distillation of liquefied air. Its rarity and the energy-intensive production process make it one of the most expensive industrial gases.

Xenon Element Properties

Explore the complete physical and chemical properties of Xenon (Xe, element 54) — from its noble-gas electron configuration to its roles in lighting, anesthesia, and ion propulsion.

131.29

Xenon

Noble Gas · Period 5 · Group 18

Melting Point

-111.75 °C

Boiling Point

-108.12 °C

Density (gas)

5.894 g/L

Atomic Mass

131.293 u

Electron Shell Configuration

[Kr] 4d¹⁰ 5s² 5p⁶

Shells: 2, 8, 18, 18, 8

Filter Properties

Property	Value
Element Name	Xenon
Symbol	Xe
Atomic Number	54
Atomic Mass	131.293 u
Category	Noble Gas
Group	18 (VIIIA / Noble Gases)
Period	5
Block	p-block
CAS Number	7440-63-3
Discovered	1898 by William Ramsay and Morris Travers
Named After	Greek xenos, meaning stranger or foreign
Standard State	Gas at 25 °C
Appearance	Colorless, odorless gas; emits blue glow when excited
Crystal Structure	Face-centered cubic (below -111.75 °C)
Natural Abundance	~87 ppb by volume in Earth's atmosphere

Property	Value
Electron Configuration	[Kr] 4d10 5s2 5p6
Electrons Per Shell	2, 8, 18, 18, 8
Number of Protons	54
Number of Neutrons (Xe-132)	78
Number of Electrons	54
Valence Electrons	8
Oxidation States	0, +2, +4, +6, +8 (0 most stable)
Electronegativity (Pauling)	2.6
Electron Affinity	-77 kJ/mol (repulsive; does not form stable anion)
First Ionization Energy	1170.4 kJ/mol
Second Ionization Energy	2046.4 kJ/mol
Third Ionization Energy	3099.4 kJ/mol
Atomic Radius (calc.)	108 pm
Covalent Radius	130 pm
Van der Waals Radius	216 pm
Stable Isotopes	Xe-132 (26.9%), Xe-129 (26.4%), Xe-131 (21.2%), Xe-134 (10.4%), Xe-136 (8.9%)

Property	Value
Melting Point	-111.75 °C (-169.15 °F / 161.40 K)
Boiling Point	-108.12 °C (-162.62 °F / 165.03 K)
Critical Temperature	16.58 °C (289.73 K)
Critical Pressure	5.84 MPa
Density (gas, 0 °C, 1 atm)	5.894 g/L
Density (liquid, at b.p.)	2.942 g/cm³
Density (solid)	3.540 g/cm³
Heat of Fusion	2.27 kJ/mol
Heat of Vaporization	12.64 kJ/mol
Specific Heat Capacity	0.158 J/(g·K) (at 25 °C)
Thermal Conductivity	0.00565 W/(m·K) (at 300 K)
Speed of Sound	169 m/s (gas, at 25 °C)
Dynamic Viscosity	2.23×10⁻⁵ Pa·s (at 25 °C)
Crystal Structure	Face-centered cubic (fcc)
Magnetic Ordering	Diamagnetic
Refractive Index	1.000702 (at 0 °C, 589 nm)

Property	Value
Reactivity	Very low; noble gas with full valence shell
Known Compounds	XeF2, XeF4, XeF6, XeO3, XeO4, XeOF4, XePtF6
First Noble Gas Compound	XePtF6 synthesized by Neil Bartlett in 1962
Reaction with Fluorine	Reacts with F2 at high pressure/temperature to form XeF2, XeF4, XeF6
Reaction with Air	None under normal conditions
Reaction with Water	XeF2 and XeF4 hydrolyze slowly; XeF6 reacts vigorously
Lighting Use	High-intensity discharge (HID) xenon arc lamps for cinema and vehicle HID headlights
Semiconductor Use	Excimer lasers (XeCl, XeF) for UV photolithography of chips
Medical Anesthesia	Non-metabolized general anesthetic at ~63% inspired; low side effects
Nuclear Medicine	Xe-133 (radioactive) used as pulmonary ventilation imaging agent
Space Propulsion	Preferred propellant for ion thrusters (Dawn, Hayabusa2, BepiColombo)
Cryogenic Cooling	Liquid xenon detector medium in dark matter and neutrino experiments
Flash Photography	Xenon flash tubes used in photography and stroboscopes
NMR Spectroscopy	Hyperpolarized Xe-129 as NMR/MRI contrast agent for lung imaging
Global Production	~40,000 kg/year; produced by fractional distillation of liquid air
Atmospheric Abundance	87 ppb by volume (one of rarest stable atmospheric gases)

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Summary

Xenon (Xe) is element 54 on the periodic table, a colorless, odorless noble gas in group 18, period 5. Discovered in 1898 by William Ramsay and Morris Travers through fractional distillation of liquefied air, it is one of the rarest naturally occurring stable elements on Earth. Despite being a noble gas, Xenon forms a small number of genuine chemical compounds — notably xenon difluoride (XeF2), xenon tetrafluoride (XeF4), and xenon hexafluoroplatinate — making it the first noble gas proven to be chemically reactive. Today Xenon is used in high-intensity arc lamps, semiconductor lithography light sources, medical anesthesia, pulmonary ventilation scintigraphy tracers, and as the propellant in ion thrusters for spacecraft. This reference tool presents all key physical, atomic, and chemical properties of Xenon in one organized view.

How it works

All Xenon property data is embedded directly in the page — no server call is needed.
Use the section tabs (Overview, Atomic, Physical, Chemical) to navigate different property groups.
Click any property row to copy its value to your clipboard.
The electron configuration diagram shows the shell distribution visually.
Use the search box to filter properties by name or value.

Use cases

Quick reference for students studying noble gases and group 18 elements.
Verify Xenon specs during semiconductor lithography or lighting system design.
Teaching aid for demonstrating noble gas chemistry and exceptions to the octet rule.
Look up Xenon propellant properties for ion thruster or spacecraft design.
Cross-check Xenon anesthetic properties for medical research.
Support chemistry homework and exam preparation on noble gases.
Reference oxidation states and compound data for inorganic chemistry problems.
Explore Xenon isotope abundance for nuclear physics or medical imaging work.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu