View source for Isotopes of xenon

{{infobox xenon isotopes}}
Naturally occurring [[xenon]] (<sub>54</sub>Xe) consists of seven [[stable isotope|stable]] [[isotope]]s and two very long-lived isotopes. [[Double electron capture]] has been observed in <sup>124</sup>Xe (half-life {{nowrap|1.8 ± 0.5(stat) ± 0.1(sys) {{e|22}} years}})<ref name="XENON1T" /> and [[double beta decay]] in <sup>136</sup>Xe (half-life {{nowrap|2.165 ± 0.016(stat) ± 0.059(sys) {{e|21}} years}}),<ref name="Albert2013" /> which are among the longest measured half-lives of all nuclides. The isotopes <sup>126</sup>Xe and <sup>134</sup>Xe are also predicted to undergo double beta decay,{{AME2016 II|ref}} but this has never been observed in these isotopes, so they are considered to be stable.<ref>[http://www.shef.ac.uk/physics/bus2006/talks/luscher_roland.pdf Status of ββ-decay in Xenon], Roland Lüscher, accessed online September 17, 2007.  {{webarchive |url=https://web.archive.org/web/20070927183750/http://www.shef.ac.uk/physics/bus2006/talks/luscher_roland.pdf |date=September 27, 2007 }}</ref><ref name="xenon2b">{{cite journal |last1=Barros |first1=N. |last2=Thurn |first2=J. |last3=Zuber |first3=K. |title=Double beta decay searches of <sup>134</sup>Xe, <sup>126</sup>Xe, and <sup>124</sup>Xe with large scale Xe detectors |date=2014 |journal=[[Journal of Physics G]] |volume=41 |issue=11 |pages=115105–1–115105–12 |doi=10.1088/0954-3899/41/11/115105 |arxiv=1409.8308 |s2cid=116264328 }}</ref> Beyond these stable forms, 32 artificial [[unstable isotope]]s and various isomers have been studied, the longest-lived of which is <sup>127</sup>Xe with a [[half-life]] of 36.345 days. All other isotopes have half-lives less than 12 days, most less than 20 hours. The shortest-lived isotope, <sup>108</sup>Xe,<ref name="Xe108">{{cite journal |last=Auranen |first=K. |display-authors=etal |date=2018 |title=Superallowed α decay to doubly magic <sup>100</sup>Sn |journal=Physical Review Letters |volume=121 |issue=18 |pages=182501 |doi=10.1103/PhysRevLett.121.182501 |pmid=30444390 |url=https://www.pure.ed.ac.uk/ws/files/77942573/PhysRevLett.121.pdf |doi-access=free }}</ref> has a half-life of 58&nbsp;μs, and is the heaviest known nuclide with equal numbers of protons and neutrons. Of known isomers, the longest-lived is <sup>131m</sup>Xe with a half-life of 11.934 days. <sup>129</sup>Xe is produced by [[beta decay]] of [[iodine-129|<sup>129</sup>I]] ([[half-life]]: 16 million years); <sup>131m</sup>Xe, <sup>133</sup>Xe, <sup>133m</sup>Xe, and <sup>135</sup>Xe are some of the [[fission product]]s of both [[uranium-235|<sup>235</sup>U]] and [[plutonium-239|<sup>239</sup>Pu]], so are used as indicators of [[nuclear explosion]]s.

The artificial isotope [[Xenon-135|<sup>135</sup>Xe]] is of considerable significance in the operation of [[nuclear reactor|nuclear fission reactors]]. <sup>135</sup>Xe has a huge [[neutron cross section|cross section]] for [[thermal neutron]]s, 2.65×10<sup>6</sup> [[Barn (unit)|barns]], so it acts as a [[neutron absorber]] or "[[nuclear poison|poison]]" that can [[iodine pit|slow or stop]] the chain reaction after a period of operation. This was discovered in the [[Hanford B Reactor|earliest nuclear reactors]] built by the American [[Manhattan Project]] for [[plutonium]] production.  Because of this effect, designers must make provisions to increase the reactor's [[reactivity (nuclear)|reactivity]] (the number of neutrons per fission that go on to fission other atoms of nuclear fuel) over the initial value needed to start the chain reaction.

Relatively high concentrations of radioactive xenon isotopes are also found emanating from nuclear reactors due to the release of this fission gas from cracked [[fuel rod]]s or fissioning of uranium in cooling water.{{citation needed|date=April 2017}} The concentrations of these isotopes are still usually low compared to the naturally occurring radioactive [[noble gas]] [[radon-222|<sup>222</sup>Rn]].

Because xenon is a [[isotopic tracer|tracer]] for two [[parent isotope]]s, Xe [[isotopic signature|isotope ratios]] in [[meteorite]]s are a powerful tool for studying the [[formation of the solar system]]. The I-Xe method of [[Radiometric dating|dating]] gives the time elapsed between [[nucleosynthesis]] and the condensation of a solid object from the [[solar nebula]] (xenon being a gas, only that part of it that formed after condensation will be present inside the object). Xenon isotopes are also a powerful tool for understanding [[Planetary differentiation|terrestrial differentiation]]. Excess <sup>129</sup>Xe found in [[carbon dioxide]] well gases from [[New Mexico]] was believed to be from the decay of [[Mantle (geology)|mantle]]-derived gases soon after Earth's formation.<ref>{{cite journal
  | last1 = Boulos
  | first1 = M. S.
  |last2=Manuel |first2=O. K.
  | title = The xenon record of extinct radioactivities in the Earth.
  | journal = [[Science (journal)|Science]]
  | volume = 174
  | issue = 4016
  | pages = 1334–1336
  | year = 1971
  | doi = 10.1126/science.174.4016.1334
  | pmid = 17801897 |bibcode = 1971Sci...174.1334B | s2cid = 28159702
 }}</ref>

== List of isotopes ==
{{Isotopes table
|symbol=Xe
|refs=<!-- not NUBASE2016 yet (2019-07-14) -->
|notes=m, unc(), mass#, hl-nst, spin(), spin#, daughter-st, EC, IT, n
}}
|-
| <sup>108</sup>Xe<ref name="Xe108" />
| style="text-align:right" | 54
| style="text-align:right" | 54
| 
| 58(+106−23)&nbsp;μs
| [[alpha decay|α]]
| <sup>104</sup>Te
| 0+
|
|
|-
| <sup>109</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 55
| 
| 13(2)&nbsp;ms
| α
| <sup>105</sup>Te
|
|
|
|-
| rowspan=2|<sup>110</sup>Xe
| rowspan=2 style="text-align:right" | 54
| rowspan=2 style="text-align:right" | 56
| rowspan=2|109.94428(14)
| rowspan=2|310(190)&nbsp;ms<br>[105(+35−25)&nbsp;ms]
| [[beta decay|β<sup>+</sup>]]
| <sup>110</sup>I
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| α
| <sup>106</sup>Te
|-
| rowspan=2|<sup>111</sup>Xe
| rowspan=2 style="text-align:right" | 54
| rowspan=2 style="text-align:right" | 57
| rowspan=2|110.94160(33)#
| rowspan=2|740(200)&nbsp;ms
| β<sup>+</sup> (90%)
| <sup>111</sup>I
| rowspan=2|5/2+#
| rowspan=2|
| rowspan=2|
|-
| α (10%)
| <sup>107</sup>Te
|-
| rowspan=2|<sup>112</sup>Xe
| rowspan=2 style="text-align:right" | 54
| rowspan=2 style="text-align:right" | 58
| rowspan=2|111.93562(11)
| rowspan=2|2.7(8)&nbsp;s
| β<sup>+</sup> (99.1%)
| <sup>112</sup>I
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| α (.9%)
| <sup>108</sup>Te
|-
| rowspan=4|<sup>113</sup>Xe
| rowspan=4 style="text-align:right" | 54
| rowspan=4 style="text-align:right" | 59
| rowspan=4|112.93334(9)
| rowspan=4|2.74(8)&nbsp;s
| β<sup>+</sup> (92.98%)
| <sup>113</sup>I
| rowspan=4|(5/2+)#
| rowspan=4|
| rowspan=4|
|-
| β<sup>+</sup>, [[proton emission|p]] (7%)
| <sup>112</sup>Te
|-
| α (.011%)
| <sup>109</sup>Te
|-
| β<sup>+</sup>, α (.007%)
| <sup>109</sup>Sb
|-
| <sup>114</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 60
| 113.927980(12)
| 10.0(4)&nbsp;s
| β<sup>+</sup>
| <sup>114</sup>I
| 0+
|
|
|-
| rowspan=3|<sup>115</sup>Xe
| rowspan=3 style="text-align:right" | 54
| rowspan=3 style="text-align:right" | 61
| rowspan=3|114.926294(13)
| rowspan=3|18(4)&nbsp;s
| β<sup>+</sup> (99.65%)
| <sup>115</sup>I
| rowspan=3|(5/2+)
| rowspan=3|
| rowspan=3|
|-
| β<sup>+</sup>, p (.34%)
| <sup>114</sup>Te
|-
| β<sup>+</sup>, α (3×10<sup>−4</sup>%)
| <sup>111</sup>Sb
|-
| <sup>116</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 62
| 115.921581(14)
| 59(2)&nbsp;s
| β<sup>+</sup>
| <sup>116</sup>I
| 0+
|
|
|-
| rowspan=2|<sup>117</sup>Xe
| rowspan=2 style="text-align:right" | 54
| rowspan=2 style="text-align:right" | 63
| rowspan=2|116.920359(11)
| rowspan=2|61(2)&nbsp;s
| β<sup>+</sup> (99.99%)
| <sup>117</sup>I
| rowspan=2|5/2(+)
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>, p (.0029%)
| <sup>116</sup>Te
|-
| <sup>118</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 64
| 117.916179(11)
| 3.8(9)&nbsp;min
| β<sup>+</sup>
| <sup>118</sup>I
| 0+
|
|
|-
| <sup>119</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 65
| 118.915411(11)
| 5.8(3)&nbsp;min
| β<sup>+</sup>
| <sup>119</sup>I
| 5/2(+)
|
|
|-
| <sup>120</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 66
| 119.911784(13)
| 40(1)&nbsp;min
| β<sup>+</sup>
| <sup>120</sup>I
| 0+
|
|
|-
| <sup>121</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 67
| 120.911462(12)
| 40.1(20)&nbsp;min
| β<sup>+</sup>
| <sup>121</sup>I
| (5/2+)
|
|
|-
| <sup>122</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 68
| 121.908368(12)
| 20.1(1)&nbsp;h
| β<sup>+</sup>
| <sup>122</sup>I
| 0+
|
|
|-
| <sup>123</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 69
| 122.908482(10)
| 2.08(2)&nbsp;h
| [[Electron capture|EC]]
| <sup>123</sup>I
| 1/2+
|
|
|-
| style="text-indent:1em" | <sup>123m</sup>Xe
| colspan="3" style="text-indent:2em" | 185.18(22)&nbsp;keV
| 5.49(26)&nbsp;μs
|
|
| 7/2(−)
|
|
|-
| <sup>124</sup>Xe<ref group="n" name="PN">[[Primordial nuclide|Primordial]] [[radionuclide]]</ref>
| style="text-align:right" | 54
| style="text-align:right" | 70
| 123.905893(2)
| '''1.8(0.5 (stat), 0.1 (sys)){{e|22}}&nbsp;y'''<ref name="XENON1T" />
| [[Double electron capture|Double EC]]
| '''<sup>124</sup>Te''' 
| 0+
| 9.52(3)×10<sup>−4</sup>
|
|-
| <sup>125</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 71
| 124.9063955(20)
| 16.9(2)&nbsp;h
| β<sup>+</sup>
| <sup>125</sup>I
| 1/2(+)
|
|
|-
| style="text-indent:1em" | <sup>125m1</sup>Xe
| colspan="3" style="text-indent:2em" | 252.60(14)&nbsp;keV
| 56.9(9)&nbsp;s
| [[Isomeric transition|IT]]
| <sup>125</sup>Xe
| 9/2(−)
|
|
|-
| style="text-indent:1em" | <sup>125m2</sup>Xe
| colspan="3" style="text-indent:2em" | 295.86(15)&nbsp;keV
| 0.14(3)&nbsp;μs
|
|
| 7/2(+)
|
|
|-
| <sup>126</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 72
| 125.904274(7)
| colspan=3 align=center|'''[[Observationally Stable]]'''<ref group="n">Suspected of undergoing β<sup>+</sup>β<sup>+</sup> decay to '''<sup>126</sup>Te'''</ref>
| 0+
| 8.90(2)×10<sup>−4</sup>
|
|-
| <sup>127</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 73
| 126.905184(4)
| 36.345(3)&nbsp;d
| EC
| '''<sup>127</sup>I'''
| 1/2+
|
|
|-
| style="text-indent:1em" | <sup>127m</sup>Xe
| colspan="3" style="text-indent:2em" | 297.10(8)&nbsp;keV
| 69.2(9)&nbsp;s
| IT
| <sup>127</sup>Xe
| 9/2−
|
|
|-
| <sup>128</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 74
| 127.9035313(15)
| colspan=3 align=center|'''Stable'''<ref group="n" name="SF">Theoretically capable of [[spontaneous fission]]</ref>
| 0+
| 0.019102(8)
|
|-
| <sup>129</sup>Xe<ref group="n">Used in a method of [[Iodine-129#Applications|radiodating]] groundwater and to infer certain events in the Solar System's history</ref>
| style="text-align:right" | 54
| style="text-align:right" | 75
| 128.9047794(8)
| colspan=3 align=center|'''Stable'''<ref group="n" name="SF" />
| 1/2+
| 0.264006(82)
|
|-
| style="text-indent:1em" | <sup>129m</sup>Xe
| colspan="3" style="text-indent:2em" | 236.14(3)&nbsp;keV
| 8.88(2)&nbsp;d
| IT
| '''<sup>129</sup>Xe'''
| 11/2−
|
|
|-
| <sup>130</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 76
| 129.9035080(8)
| colspan=3 align=center|'''Stable'''<ref group="n" name="SF" />
| 0+
| 0.040710(13)
|
|-
| <sup>131</sup>Xe<ref group="n" name="FP">[[Fission product]]</ref>
| style="text-align:right" | 54
| style="text-align:right" | 77
| 130.9050824(10)
| colspan=3 align=center|'''Stable'''<ref group="n" name="SF" />
| 3/2+
| 0.212324(30)
|
|-
| style="text-indent:1em" | <sup>131m</sup>Xe
| colspan="3" style="text-indent:2em" | 163.930(8)&nbsp;keV
| 11.934(21)&nbsp;d
| IT
| '''<sup>131</sup>Xe'''
| 11/2−
|
|
|-
| <sup>132</sup>Xe<ref group="n" name="FP" />
| style="text-align:right" | 54
| style="text-align:right" | 78
| 131.9041535(10)
| colspan=3 align=center|'''Stable'''<ref group="n" name="SF" />
| 0+
| 0.269086(33)
|
|-
| style="text-indent:1em" | <sup>132m</sup>Xe
| colspan="3" style="text-indent:2em" | 2752.27(17)&nbsp;keV
| 8.39(11)&nbsp;ms
| IT
| '''<sup>132</sup>Xe'''
| (10+)
|
|
|-
| <sup>133</sup>Xe<ref group="n" name="FP" /><ref group="n">Has [[nuclear medicine|medical uses]]</ref>
| style="text-align:right" | 54
| style="text-align:right" | 79
| 132.9059107(26)
| 5.2475(5)&nbsp;d
| β<sup>−</sup>
| '''<sup>133</sup>Cs'''
| 3/2+
|
|
|-
| style="text-indent:1em" | <sup>133m</sup>Xe
| colspan="3" style="text-indent:2em" | 233.221(18)&nbsp;keV
| 2.19(1)&nbsp;d
| IT
| <sup>133</sup>Xe
| 11/2−
|
|
|-
| <sup>134</sup>Xe<ref group="n" name="FP" />
| style="text-align:right" | 54
| style="text-align:right" | 80
| 133.9053945(9)
| colspan=3 align=center|'''Observationally Stable'''<ref group="n">Suspected of undergoing β<sup>−</sup>β<sup>−</sup> decay to '''<sup>134</sup>Ba''' with a half-life over 11×10<sup>15</sup> years</ref>
| 0+
| 0.104357(21)
|
|-
| style="text-indent:1em" | <sup>134m1</sup>Xe
| colspan="3" style="text-indent:2em" | 1965.5(5)&nbsp;keV
| 290(17)&nbsp;ms
| IT
| '''<sup>134</sup>Xe'''
| 7−
|
|
|-
| style="text-indent:1em" | <sup>134m2</sup>Xe
| colspan="3" style="text-indent:2em" | 3025.2(15)&nbsp;keV
| 5(1)&nbsp;μs
|
|
| (10+)
|
|
|-
| [[Xenon-135|<sup>135</sup>Xe]]<ref group="n">Most powerful known [[neutron absorber]], produced in nuclear power plants as a [[decay product]] of <sup>135</sup>I, itself a decay product of <sup>135</sup>Te, a [[fission product]]. Normally absorbs neutrons in the high [[neutron flux]] environments to become '''''<sup>136</sup>Xe'''''; see [[iodine pit]] for more information</ref>
| style="text-align:right" | 54
| style="text-align:right" | 81
| 134.907227(5)
| 9.14(2)&nbsp;h
| β<sup>−</sup>
| <sup>135</sup>Cs
| 3/2+
|
|
|-
| rowspan=2 style="text-indent:1em" | <sup>135m</sup>Xe
| rowspan=2 colspan="3" style="text-indent:2em" | 526.551(13)&nbsp;keV
| rowspan=2|15.29(5)&nbsp;min
| IT (99.99%)
| <sup>135</sup>Xe
| rowspan=2|11/2−
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup> (.004%)
| <sup>135</sup>Cs
|-
| <sup>136</sup>Xe<ref group="n" name="PN">[[Primordial nuclide|Primordial]] [[radionuclide]]</ref>
| style="text-align:right" | 54
| style="text-align:right" | 82
| 135.907219(8)
| '''2.165(0.016 (stat), 0.059 (sys)){{e|21}}&nbsp;y'''<ref name="Albert2013" />
|β<sup>−</sup>β<sup>−</sup>
| '''<sup>136</sup>Ba'''
| 0+
| 0.088573(44)
|
|-
| style="text-indent:1em" | <sup>136m</sup>Xe
| colspan="3" style="text-indent:2em" | 1891.703(14)&nbsp;keV
| 2.95(9)&nbsp;μs
|
| 
| 6+
|
|
|-
| <sup>137</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 83
| 136.911562(8)
| 3.818(13)&nbsp;min
| β<sup>−</sup>
| <sup>137</sup>Cs
| 7/2−
|
|
|-
| <sup>138</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 84
| 137.91395(5)
| 14.08(8)&nbsp;min
| β<sup>−</sup>
| <sup>138</sup>Cs
| 0+
|
|
|-
| <sup>139</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 85
| 138.918793(22)
| 39.68(14)&nbsp;s
| β<sup>−</sup>
| <sup>139</sup>Cs
| 3/2−
|
|
|-
| <sup>140</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 86
| 139.92164(7)
| 13.60(10)&nbsp;s
| β<sup>−</sup>
| <sup>140</sup>Cs
| 0+
|
|
|-
| rowspan=2|<sup>141</sup>Xe
| rowspan=2 style="text-align:right" | 54
| rowspan=2 style="text-align:right" | 87
| rowspan=2|140.92665(10)
| rowspan=2|1.73(1)&nbsp;s
| β<sup>−</sup> (99.45%)
| <sup>141</sup>Cs
| rowspan=2|5/2(−#)
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup>, [[neutron emission|n]] (.043%)
| <sup>140</sup>Cs
|- 
| rowspan=2|<sup>142</sup>Xe
| rowspan=2 style="text-align:right" | 54
| rowspan=2 style="text-align:right" | 88
| rowspan=2|141.92971(11)
| rowspan=2|1.22(2)&nbsp;s
| β<sup>−</sup> (99.59%)
| <sup>142</sup>Cs
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup>, n (.41%)
| <sup>141</sup>Cs
|-
| <sup>143</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 89
| 142.93511(21)#
| 0.511(6)&nbsp;s
| β<sup>−</sup>
| <sup>143</sup>Cs
| 5/2−
|
|
|-
| rowspan=2|<sup>144</sup>Xe
| rowspan=2 style="text-align:right" | 54
| rowspan=2 style="text-align:right" | 90
| rowspan=2|143.93851(32)#
| rowspan=2|0.388(7)&nbsp;s
| β<sup>−</sup>
| <sup>144</sup>Cs
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup>, n
| <sup>143</sup>Cs
|-
| <sup>145</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 91
| 144.94407(32)#
| 188(4)&nbsp;ms
| β<sup>−</sup>
| <sup>145</sup>Cs
| (3/2−)#
|
|
|-
| <sup>146</sup>Xe
| style="text-align:right" | 54
| style="text-align:right" | 92
| 145.94775(43)#
| 146(6)&nbsp;ms
| β<sup>−</sup>
| <sup>146</sup>Cs
| 0+
|
|
|-
| rowspan=2|<sup>147</sup>Xe
| rowspan=2 style="text-align:right" | 54
| rowspan=2 style="text-align:right" | 93
| rowspan=2|146.95356(43)#
| rowspan=2|130(80)&nbsp;ms<br>[0.10(+10−5)&nbsp;s]
| β<sup>−</sup>
| <sup>147</sup>Cs
| rowspan=2|3/2−#
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup>, n
| <sup>146</sup>Cs
{{Isotopes table/footer}}
* The isotopic composition refers to that in air.

==Xenon-124==
Xenon-124 is an isotope of xenon that undergoes double electron capture to [[tellurium]]-124 with a very long half life of {{val|1.8|e=22}} years, more than 12 orders of magnitude longer than the age of the universe ({{val|13.799|0.021|e=9|u=years}}).  Such decays have been observed in the [[XENON#XENON1T|XENON1T]] detector in 2019, and are the rarest processes ever directly observed.<ref>{{cite web |title=A Dark Matter Detector Just Recorded One of The Rarest Events Known to Science |url=https://www.sciencealert.com/a-dark-matter-detector-just-detected-one-of-the-rarest-events-ever-in-science |author=David Nield |date=26 Apr 2019}}</ref> (Even slower decays of other nuclei have been measured, but by detecting decay products that have accumulated over billions of years rather than observing them directly.<ref>{{cite journal |author=Hennecke, Edward W., O. K. Manuel, and Dwarka D. Sabu. |title=Double beta decay of Te 128 |journal=Physical Review C |volume=11 |issue=4 |date=1975 |pages=1378–1384 |doi=10.1103/PhysRevC.11.1378 |url=http://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=2240&context=chem_facwork}}</ref>)

==Xenon-133==
{{Infobox isotope
    | mass_number = 133
    | symbol = Xe
    | num_neutrons = 79  
    | num_protons = 54
    | abundance =  [[Synthetic radioisotope|syn]]
    | halflife = 5.243 [[Day|d]] (1)
    | decay_product = Caesium-133
    | decay_mass = 133
    | decay_symbol = Cs
    | mass = 132.9059107
    | spin = 3/2+
    | excess_energy =
    | error1 =
    | binding_energy =
    | error2 =
    | decay_mode1 = [[Beta decay|Beta<sup>&minus;</sup>]]
    | decay_energy1 = 0.427
    | decay_mode2 =
    | decay_energy2 =
    | decay_mode3 =
    | decay_energy3 =
    | decay_mode4 =
    | decay_energy4 =
    }} 
'''Xenon-133''' (sold as a drug under the brand name ''Xeneisol'', [[ATC code]] {{ATC|V09|EX03}}) is an isotope of xenon. It is a [[radionuclide]] that is [[Ventilation/perfusion scan|inhaled]] to assess pulmonary function, and to image the [[lung]]s.<ref>{{Cite journal 
| last1 = Jones | first1 = R. L. 
| last2 = Sproule | first2 = B. J. 
| last3 = Overton | first3 = T. R. 
| title = Measurement of regional ventilation and lung perfusion with Xe-133 
| journal = Journal of Nuclear Medicine
| volume = 19 
| issue = 10 
| pages = 1187–1188 
| year = 1978 
| pmid = 722337
}}</ref> It is also used to image blood flow, particularly in the [[brain]].<ref>{{Cite journal 
| last1 = Hoshi | first1 = H. 
| last2 = Jinnouchi | first2 = S. 
| last3 = Watanabe | first3 = K. 
| last4 = Onishi | first4 = T. 
| last5 = Uwada | first5 = O. 
| last6 = Nakano | first6 = S. 
| last7 = Kinoshita | first7 = K. 
| title = Cerebral blood flow imaging in patients with brain tumor and arterio-venous malformation using Tc-99m hexamethylpropylene-amine oxime--a comparison with Xe-133 and IMP 
| journal = Kaku Igaku 
| volume = 24 
| issue = 11 
| pages = 1617–1623 
| year = 1987 
| pmid = 3502279
}}</ref> <sup>133</sup>Xe is also an important [[fission product]].{{citation needed|date=October 2012}} It is discharged to the atmosphere in small quantities by some nuclear power plants.<ref name=":0">{{Cite book |url=https://www.ncbi.nlm.nih.gov/books/NBK201991/ |title=Effluent Releases from Nuclear Power Plants and Fuel-Cycle Facilities |date=2012-03-29 |publisher=National Academies Press (US) |language=en }}</ref>

==Xenon-135==
{{main|Xenon-135}}

'''Xenon-135''' is a [[radioactive isotope]] of [[xenon]], produced as a [[fission product]] of uranium. It has a [[half-life]] of about 9.2 hours and is the most powerful known [[neutron]]-absorbing [[nuclear poison]] (having a [[Neutron cross section|neutron absorption cross-section]] of 2 million [[Barn (unit)|barns]]<ref>Chart of the Nuclides 13th Edition</ref>). The overall yield of xenon-135 from fission is 6.3%, though most of this results from the radioactive decay of fission-produced [[tellurium-135]] and [[iodine-135]]. Xe-135 exerts a significant effect on [[nuclear reactor]] operation ([[xenon pit]]). It is discharged to the atmosphere in small quantities by some nuclear power plants.<ref name=":0" />

==Xenon-136==
Xenon-136 is an isotope of xenon that undergoes double beta decay to [[barium]]-136 with a very long half life of {{val|2.11|e=21}} years, more than 10 orders of magnitude longer than the age of the universe ({{val|13.799|0.021|e=9|u=years}}). It is being used in the [[Enriched Xenon Observatory]] experiment to search for [[neutrinoless double beta decay]].

==References==
{{Reflist}}
* Isotope masses from [http://amdc.in2p3.fr/web/masseval.html Ame2003 Atomic Mass Evaluation] by Georges Audi, Aaldert Hendrik Wapstra, Catherine Thibault, Jean Blachot and Olivier Bersillon in ''Nuclear Physics'' A729 (2003).
* Isotopic compositions and standard atomic masses from:
**{{CAWIA 2003}}
**{{CIAAW 2005}}
* Half-life, spin, and isomer data selected from the following sources.
**{{NUBASE 2003}}
**{{NNDC}}
**{{CRC85|chapter=11}}

{{Navbox element isotopes}}

[[Category:Isotopes of xenon| ]]
[[Category:Xenon]]
[[Category:Lists of isotopes by element|Xenon]]