Skip to Main Content

About Xenon

Xenon Bohr

Xenon is a rare noble gas with abundance estimated at 0.1 ppm in Earth’s atmosphere, and it’s for this reason that xenon was one of the last gases to be isolated. As with other noble gases, it was isolated by Sir William Ramsay and Morris Travers in 1898 during their research on fractional distillation of liquefied air. To this day, xenon is only produced via this method, although efficiency has increased over the decades. Xenon was long thought to be completely inactive until it became the first noble gas to be synthesized into a chemical compound, the element bonding with a form platinum fluoride to form xenon hexafluoroplatinate. Scientific research since the 1960s has yielded several other exotic compounds, none which have yet produced any known applications outside of scientific circles.

Along with the other noble gases like helium, xenon’s primary application is in lighting. Xenon produces an extremely bright bluish-white light useful in photographic flashes and lighting equipment. Strobe lights contain an amount of xenon for this reason. And because the light emitted by xenon is so strong, this element is also utilized in lasers and bacteria-killing ultraviolet light sources to sterilize lab equipment. In the medical industry, xenon is used as a general anesthetic, and several isotopes are utilized in the study of blood flow through the brain and lungs. Xenon is even used in ion thrusters for deep-space spacecraft. Observation of xenon content is also useful in dating events in the early solar system.

Xenon has eight stable isotopes (the most of any element next to tin), and over 40 known unstable isotopes, some of which are radioactive.  135Xe is often used as a neutron absorber that can slow or stop nuclear reactions, but Chernobyl has taught the scientific community that powering down a reactor without accounting for the ensuing buildup of xenon can further poison the whole reactor.  Along with 133Xe, 135Xe is also used as an observable barometer to monitor compliance with nuclear test ban treaties or to confirm that a nuclear detonation has taken place.  Liquid xenon is used in calorimeters for measurements of gamma rays and as a medium to detect weakly interacting massive particles.

Xenon Products

Xenon Properties

Xenon Bohr ModelXenon is a Block P, Group 18, Period 5 element. The number of electrons in each of Xenon's shells is 2, 8, 18, 18, 8 and its electronic configuration is [Kr] 4d10 5s2 5p6. In its elemental form xenon's CAS number is 7440-63-3. The xenon atom has a covalent radius of 140± and it's Van der Waals radius is Xenon is present in the atmosphere and is commercially produced as a byproduct of the separation of air into oxygen and nitrogen. Xenon was discovered and first isolated by Sir William Ramsay and Morris W. Travers in 1898. Xenon is named from the Greek word xenon meaning foreign or strange.

Xenon information, including technical data, properties, and other useful facts are specified below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity, and thermal properties are included.

Symbol: Xe
Atomic Number: 54
Atomic Weight: 131.3
Element Category: noble gases
Group, Period, Block: 18, 5, p
Color: colorless
Other Names: Xeno
Melting Point: -111.74°C, -169.132°F, 161.41 K
Boiling Point: -108.099°C, -162.578°F, 165.051 K
Density: 3560 (88 K) kg·m3
Liquid Density @ Melting Point: 3.057 g·cm3
Density @ 20°C: 0.00588 g/cm3
Density of Solid: 3640 kg·m3
Specific Heat: N/A
Superconductivity Temperature: N/A
Triple Point: 161.405 K, 81.77 kPa
Critical Point: 289.733 K, 5.842 MPa
Heat of Fusion (kJ·mol-1): 3.1
Heat of Vaporization (kJ·mol-1): 12.65
Heat of Atomization (kJ·mol-1): 0
Thermal Conductivity: 5.65×10-3  W·m-1·K-1
Thermal Expansion: N/A
Electrical Resistivity: N/A
Tensile Strength: N/A
Molar Heat Capacity: 5R/2 = 20.786 J·mol-1·K-1
Young's Modulus: N/A
Shear Modulus: N/A
Bulk Modulus: N/A
Poisson Ratio: N/A
Mohs Hardness: N/A
Vickers Hardness: N/A
Brinell Hardness: N/A
Speed of Sound: (liquid) 1090 m/s; (gas) 169 m·s-1
Pauling Electronegativity: 2.6
Sanderson Electronegativity: 2.34
Allred Rochow Electronegativity: 2.4
Mulliken-Jaffe Electronegativity: 2.73 (12.5% s orbital)
Allen Electronegativity: 2.582
Pauling Electropositivity: 1.4
Reflectivity (%): N/A
Refractive Index: 1.000702
Electrons: 54
Protons: 54
Neutrons: 77
Electron Configuration: [Kr] 4d10 5s2 5p6
Atomic Radius: N/A
Atomic Radius,
non-bonded (Å):
Covalent Radius: 140±9 pm
Covalent Radius (Å): 1.36
Van der Waals Radius: 216 pm
Oxidation States: 0, +1, +2, +4, +6, +8 (weakly acidic oxide)
Phase: Gas
Crystal Structure: face-centered cubic
Magnetic Ordering: diamagnetic
Electron Affinity (kJ·mol-1) Not stable
1st Ionization Energy: 1170.36 kJ·mol-1
2nd Ionization Energy: 2046.45 kJ·mol-1
3rd Ionization Energy: 3099.42 kJ·mol-1
CAS Number: 7440-63-3
EC Number: N/A
MDL Number: MFCD00083855
Beilstein Number: N/A
SMILES Identifier: [Xe]
InChI Identifier: InChI=1S/Xe
PubChem CID: 23991
ChemSpider ID: 22427
Earth - Total: 0.0168E-8 cm^3/g
Mercury - Total: N/A
Venus - Total: 1.61E-8 cm^3/g 
Earth - Seawater (Oceans), ppb by weight: 0.005
Earth - Seawater (Oceans), ppb by atoms: 0.00024
Earth -  Crust (Crustal Rocks), ppb by weight: 0.02
Earth -  Crust (Crustal Rocks), ppb by atoms: 0.003
Sun - Total, ppb by weight: N/A
Sun - Total, ppb by atoms: N/A
Stream, ppb by weight: N/A
Stream, ppb by atoms: N/A
Meterorite (Carbonaceous), ppb by weight: N/A
Meterorite (Carbonaceous), ppb by atoms: N/A
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 10
Universe, ppb by atom: 0.09
Discovered By: William Ramsay and Morris Travers
Discovery Date: 1898
First Isolation: William Ramsay and Morris Travers (1898)

Health, Safety & Transportation Information for Xenon

Xenon compounds are considered to be toxic although xenon itself is not. The below applies to elemental xenon.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Warning
Hazard Statements H280
Hazard Codes N/A
Risk Codes N/A
Safety Precautions N/A
RTECS Number N/A
Transport Information UN 2036 2.2
WGK Germany 1
Globally Harmonized System of
Classification and Labelling (GHS)
Gas Cylinder - Gases Under Pressure

Xenon Isotopes

Naturally occurring xenon (Xe) has eight stable isotopes: 124Xe, 126Xe, 128Xe, 129Xe, 130Xe, 131Xe, 132Xe, and 134Xe

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
110Xe 109.94428(14) 310(190) ms [105(+35-25) ms] ß+ to 110I; a to 106Te 0+ N/A 883.96 -
111Xe 110.94160(33)# 740(200) ms ß+ to 111I; a to 107Te 5/2+# N/A 892.04 -
112Xe 111.93562(11) 2.7(8) s ß+ to 112I; a to 108Te 0+ N/A 909.44 -
113Xe 112.93334(9) 2.74(8) s ß+ to 113I; ß+ + p to 112Te; a to 109Te; ß+ + a to 109Sb (5/2+)# N/A 917.52 -
114Xe 113.927980(12) 10.0(4) s ß+ to 114I 0+ N/A 934.91 -
115Xe 114.926294(13) 18(4) s ß+ to 115I; ß+ + p to 114Te; ß+ + a to 111Sb (5/2+) N/A 942.99 -
116Xe 115.921581(14) 59(2) s ß+ to 116I 0+ N/A 951.07 -
117Xe 116.920359(11) 61(2) s ß+ to 117I; ß+ + p to 116Te 5/2(+) N/A 959.15 -
118Xe 117.916179(11) 3.8(9) min ß+ to 118I 0+ N/A 976.54 -
119Xe 118.915411(11) 5.8(3) min ß+ to 119I 5/2(+) N/A 984.62 -
120Xe 119.911784(13) 40(1) min ß+ to 120I 0+ N/A 992.7 -
121Xe 120.911462(12) 40.1(20) min ß+ to 121I (5/2+) N/A 1000.78 -
122Xe 121.908368(12) 20.1(1) h EC to 122I 0+ N/A 1018.17 -
123Xe 122.908482(10) 2.08(2) h EC to 123I 1/2+ N/A 1026.25 -
124Xe 123.905893(2) Observationally Stable - 0+ N/A 1034.33 0.09
125Xe 124.9063955(20) 16.9(2) h EC to 125I 1/2(+) N/A 1042.41 -
126Xe 125.904274(7) Observationally Stable - 0+ N/A 1050.49 0.09
127Xe 126.905184(4) 36.345(3) d EC to 127I 1/2+ N/A 1058.57 -
128Xe 127.9035313(15) STABLE - 0+ N/A 1066.65 1.92
129Xe 128.9047794(8) STABLE - 1/2+ -0.777977 1074.72 26.44
130Xe 129.9035080(8) STABLE - 0+ N/A 1082.8 4.08
131Xe 130.9050824(10) STABLE - 3/2+ 0.691861 1090.88 21.18
132Xe 131.9041535(10) STABLE - 0+ N/A 1098.96 26.89
133Xe 132.9059107(26) 5.2475(5) d ß- to 133Cs 3/2+ 0.813 1107.04 -
134Xe 133.9053945(9) Observationally Stable - 0+ N/A 1115.12 10.44
135Xe 134.907227(5) 9.14(2) h ß- to 135Cs 3/2+ 0.903 1123.2 -
136Xe 135.907219(8) 2.165x 1017 y - to 136Ba 0+ N/A 1131.28 8.87
137Xe 136.911562(8) 3.818(13) min ß- to 137Cs 7/2- N/A 1130.04 -
138Xe 137.91395(5) 14.08(8) min ß- to 138Cs 0+ N/A 1138.12 -
139Xe 138.918793(22) 39.68(14) s ß- to 139Cs 3/2- N/A 1146.2 -
140Xe 139.92164(7) 13.60(10) s ß- to 140Cs 0+ N/A 1144.96 -
141Xe 140.92665(10) 1.73(1) s ß- to 141Cs; ß- + n to 140Cs 5/2(-#) N/A 1153.04 -
142Xe 141.92971(11) 1.22(2) s ß- to 142Cs; ß- + n to 141Cs 0+ N/A 1161.12 -
143Xe 142.93511(21)# 0.511(6) s ß- to 143Cs 5/2- N/A 1159.88 -
144Xe 143.93851(32)# 0.388(7) s ß- to 144Cs; ß- + n to 143Cs 0+ N/A 1167.96 -
145Xe 144.94407(32)# 188(4) ms ß- to 145Cs (3/2-)# N/A 1166.72 -
146Xe 145.94775(43)# 146(6) ms ß- to 146Cs 0+ N/A 1174.8 -
147Xe 146.95356(43)# 130(80) ms [0.10(+10-5) s] ß- to 147Cs; ß- + n to 146Cs 3/2-# N/A 1173.56 -