View source for Physics:Isotopes of uranium

{{Short description|Nuclides with atomic number of 92 but with different mass numbers}}
{{Infobox uranium isotopes}}
[[Chemistry:Uranium|Uranium]] (<sub>92</sub>U) is a naturally occurring [[Physics:Radioactive|radioactive]] element that has no [[Physics:Stable isotope|stable isotope]]. It has two primordial isotopes, [[Physics:Uranium-238|uranium-238]] and [[Physics:Uranium-235|uranium-235]], that have long half-lives and are found in appreciable quantity in the [[Earth:Earth's crust|Earth's crust]]. The [[Physics:Decay product|decay product]] [[Physics:Uranium-234|uranium-234]] is also found. Other isotopes such as [[Physics:Uranium-233|uranium-233]] have been produced in [[Engineering:Breeder reactor|breeder reactor]]s. In addition to isotopes found in nature or nuclear reactors, many isotopes with far shorter half-lives have been produced, ranging from <sup>214</sup>U to <sup>242</sup>U (with the exception of <sup>220</sup>U). The [[Physics:Standard atomic weight|standard atomic weight]] of [[Physics:Natural uranium|natural uranium]] is {{val|238.02891|(3)}}.

Naturally occurring uranium is composed of three major [[Physics:Isotope|isotope]]s, uranium-238 (99.2739–99.2752% [[Chemistry:Natural abundance|natural abundance]]), uranium-235 (0.7198–0.7202%), and uranium-234 (0.0050–0.0059%).<ref>{{cite web | title = Uranium Isotopes | url = http://www.globalsecurity.org/wmd/intro/u-isotopes.htm |publisher=GlobalSecurity.org | access-date = 14 March 2012}}</ref> All three isotopes are [[Physics:Radioactive decay|radioactive]] (i.e., they are [[Physics:Radionuclide|radioisotope]]s), and the most abundant and stable is uranium-238, with a half-life of {{val|4.4683e9|u=years}} (close to the [[Earth:Age of the Earth|age of the Earth]]).

Uranium-238 is an alpha emitter, decaying through the 18-member uranium series into [[Physics:Lead-206|lead-206]]. The decay series of uranium-235 (historically called actino-uranium) has 15 members and ends in lead-207. The constant rates of decay in these series makes comparison of the ratios of parent-to-daughter elements useful in [[Physics:Radiometric dating|radiometric dating]]. Uranium-233 is made from [[Physics:Thorium-232|thorium-232]] by [[Physics:Neutron|neutron]] bombardment.

Uranium-235 is important for both [[Physics:Nuclear reactor|nuclear reactor]]s (energy production) and [[Engineering:Nuclear weapon|nuclear weapon]]s because it is the only isotope existing in nature to any appreciable extent that is [[Physics:Nuclear fission|fissile]] in response to thermal neutrons, i.e., thermal [[Physics:Neutron capture|neutron capture]] has a high probability of inducing fission. A [[Philosophy:Chain reaction|chain reaction]] can be sustained with a sufficiently large ([[Physics:Critical mass|critical]]) mass of uranium-235. Uranium-238 is also important because it is fertile: it absorbs neutrons to produce a radioactive isotope that subsequently decays to the isotope [[Physics:Plutonium-239|plutonium-239]], which also is fissile.

==List of isotopes==
{{Isotopes table
| symbol = U
| refs = NUBASE2020, AME2020 II
| notes = m, histname, unc(), mass#, exen#, exexn#, spin(), spin#, EC, SF, CD, daughter-st, daughter-nst,
}}
|-
| <sup>214</sup>U<ref name="214U">{{cite journal|last1=Zhang|first1=Z. Y.|last2=Yang|first2=H. B.|last3=Huang|first3=M. H.|last4=Gan|first4=Z. G.|last5=Yuan|first5=C. X.|last6=Qi|first6=C.|last7=Andreyev|first7=A. N.|last8=Liu|first8=M. L.|last9=Ma|first9=L.|last10=Zhang|first10=M. M.|last11=Tian|first11=Y. L.|last12=Wang|first12=Y. S.|last13=Wang|first13=J. G.|last14=Yang|first14=C. L.|last15=Li|first15=G. S.|last16=Qiang|first16=Y. H.|last17=Yang|first17=W. Q.|last18=Chen|first18=R. F.|last19=Zhang|first19=H. B.|last20=Lu|first20=Z. W.|last21=Xu|first21=X. X.|last22=Duan|first22=L. M.|last23=Yang|first23=H. R.|last24=Huang|first24=W. X.|last25=Liu|first25=Z.|last26=Zhou|first26=X. H.|last27=Zhang|first27=Y. H.|last28=Xu|first28=H. S.|last29=Wang|first29=N.|last30=Zhou|first30=H. B.|last31=Wen|first31=X. J.|last32=Huang|first32=S.|last33=Hua|first33=W.|last34=Zhu|first34=L.|last35=Wang|first35=X.|last36=Mao|first36=Y. C.|last37=He|first37=X. T.|last38=Wang|first38=S. Y.|last39=Xu|first39=W. Z.|last40=Li|first40=H. W.|last41=Ren|first41=Z. Z.|last42=Zhou|first42=S. G.|title=New α-Emitting Isotope <sup>U</sup>214 and Abnormal Enhancement of α-Particle Clustering in Lightest Uranium Isotopes|journal=Physical Review Letters|volume=126|issue=15|year=2021|page=152502|arxiv=2101.06023|doi=10.1103/PhysRevLett.126.152502|pmid=33929212|bibcode=2021PhRvL.126o2502Z|s2cid=231627674}}</ref>
|
| style="text-align:right" | 92
| style="text-align:right" | 122
| 
| {{val|0.52|0.95|0.21|u=ms}}
| [[Physics:Alpha decay|α]]
| <sup>210</sup>Th
| 0+
|
|
|-
| rowspan=2|<sup>215</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 123
| rowspan=2|215.026720(11)
| rowspan=2|1.4(0.9) ms
| α
| <sup>211</sup>Th
| rowspan=2|5/2−#
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>?
| <sup>215</sup>Pa
|-
| <sup>216</sup>U<ref name="216,218U">{{cite journal |last1=Zhang |first1=M. M. |last2=Tian |first2=Y. L. |last3=Wang |first3=Y. S. |last4=Zhang |first4=Z. Y. |last5=Gan |first5=Z. G. |last6=Yang |first6=H. B. |last7=Huang |first7=M. H. |last8=Ma |first8=L. |last9=Yang |first9=C. L. |last10=Wang |first10=J. G. |last11=Yuan |first11=C. X. |last12=Qi |first12=C. |last13=Andreyev |first13=A. N. |last14=Huang |first14=X. Y. |last15=Xu |first15=S. Y. |last16=Zhao |first16=Z. |last17=Chen |first17=L. X. |last18=Wang |first18=J. Y. |last19=Liu |first19=M. L. |last20=Qiang |first20=Y. H. |last21=Li |first21=G. S. |last22=Yang |first22=W. Q. |last23=Chen |first23=R. F. |last24=Zhang |first24=H. B. |last25=Lu |first25=Z. W. |last26=Xu |first26=X. X. |last27=Duan |first27=L. M. |last28=Yang |first28=H. R. |last29=Huang |first29=W. X. |last30=Liu |first30=Z. |last31=Zhou |first31=X. H. |last32=Zhang |first32=Y. H. |last33=Xu |first33=H. S. |last34=Wang |first34=N. |last35=Zhou |first35=H. B. |last36=Wen |first36=X. J. |last37=Huang |first37=S. |last38=Hua |first38=W. |last39=Zhu |first39=L. |last40=Wang |first40=X. |last41=Mao |first41=Y. C. |last42=He |first42=X. T. |last43=Wang |first43=S. Y. |last44=Xu |first44=W. Z. |last45=Li |first45=H. W. |last46=Niu |first46=Y. F. |last47=Guo |first47=L. |last48=Ren |first48=Z. Z. |last49=Zhou |first49=S. G. |title=Fine structure in the α decay of the 8+ isomer in <sup>216, 218</sup>U |journal=Physical Review C |date=4 August 2022 |volume=106 |issue=2 |page=024305 |doi=10.1103/PhysRevC.106.024305 |s2cid=251359451 |language=en |issn=2469-9985}}</ref>
|
| style="text-align:right" | 92
| style="text-align:right" | 124
| 216.024760(30)
| {{val|2.25|0.63|0.40|u=ms}}
| α
| <sup>212</sup>Th
| 0+
|
|
|-
| style="text-indent:1em" | <sup>216m</sup>U
|
| colspan="3" style="text-indent:2em" | 2206 keV
| {{val|0.89|0.24|0.16|u=ms}}
| α
| <sup>212</sup>Th
| 8+
|
|
|-
| rowspan=2|<sup>217</sup>U<ref>{{cite journal |last1=Gan |first1=ZaiGuo |last2=Jiang |first2=Jian |last3=Yang |first3=HuaBin |last4=Zhang |first4=ZhiYuan |last5=Ma |first5=Long |last6=Yu |first6=Lin |last7=Wang |first7=JianGuo |last8=Tian |first8=YuLin |last9=Ding |first9=Bing |last10=Huang |first10=TianHeng |last11=Wang |first11=YongSheng |last12=Guo |first12=Song |last13=Sun |first13=MingDao |last14=Wang |first14=KaiLong |last15=Zhou |first15=ShanGui |last16=Ren |first16=ZhongZhou |last17=Zhou |first17=XiaoHong |last18=Xu |first18=HuShan |title=α decay studies of the neutron-deficient uranium isotopes 215-217U |journal=Chinese Science Bulletin |date=1 August 2016 |volume=61 |issue=22 |pages=2502–2511 |doi=10.1360/N972015-01316 |url=https://www.researchgate.net/publication/312030836 |access-date=24 June 2023|doi-access=free }}</ref>
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 125
| rowspan=2|217.024660(86)#
| rowspan=2|{{val|19.3|13.3|5.6|u=ms}}
| α
| <sup>213</sup>Th
| rowspan=2|(1/2−)
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>?
| <sup>217</sup>Pa
|-
| <sup>218</sup>U<ref name="216,218U"/>
| 
| style="text-align:right" | 92
| style="text-align:right" | 126
| 218.023505(15)
| {{val|650|80|70|u=μs}}
| α
| <sup>214</sup>Th
| 0+
| 
| 
|-
| rowspan=2 style="text-indent:1em" | <sup>218m</sup>U
| rowspan=2|
| rowspan=2 colspan="3" style="text-indent:2em" | 2117 keV
| rowspan=2|{{val|390|60|50|u=μs}}
| α
| <sup>214</sup>Th
| rowspan=2|8+
| rowspan=2|
| rowspan=2|
|-
| IT?
| <sup>218</sup>U
|-
| rowspan=2|<sup>219</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 127
| rowspan=2|219.025009(14)
| rowspan=2|60(7)&nbsp;μs
| α
| <sup>215</sup>Th
| rowspan=2|(9/2+)
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>?
| <sup>219</sup>Pa
|-
| rowspan=2|<sup>221</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 129
| rowspan=2|221.026323(77)
| rowspan=2|0.66(14)&nbsp;μs
| α
| <sup>217</sup>Th
| rowspan=2|(9/2+)
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>?
| <sup>221</sup>Pa
|-
| rowspan=2|<sup>222</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 130
| rowspan=2|222.026058(56)
| rowspan=2|4.7(0.7)&nbsp;μs
| α
| <sup>218</sup>Th
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>?
| <sup>222</sup>Pa
|-
| rowspan=2|<sup>223</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 131
| rowspan=2|223.027961(63)
| rowspan=2|65(12)&nbsp;μs
| α
| <sup>219</sup>Th
| rowspan=2|7/2+#
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>?
| <sup>223</sup>Pa
|-
| rowspan=2|<sup>224</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 132
| rowspan=2|224.027636(16)
| rowspan=2|396(17)&nbsp;μs
| α
| <sup>220</sup>Th
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>?
| <sup>224</sup>Pa
|-
| <sup>225</sup>U
|
| style="text-align:right" | 92
| style="text-align:right" | 133
| 225.029385(11)
| 62(4)&nbsp;ms
| α
| <sup>221</sup>Th
| 5/2+#
|
|
|-
| <sup>226</sup>U
|
| style="text-align:right" | 92
| style="text-align:right" | 134
| 226.029339(12)
| 269(6)&nbsp;ms
| α
| <sup>222</sup>Th
| 0+
|
|
|-
| rowspan=2|<sup>227</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 135
| rowspan=2|227.0311811(91)
| rowspan=2|1.1(0.1)&nbsp;min
| α
| <sup>223</sup>Th
| rowspan=2|(3/2+)
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>?
| <sup>227</sup>Pa
|-
| rowspan=2|<sup>228</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 136
| rowspan=2|228.031369(14)
| rowspan=2|9.1(0.2)&nbsp;min
| α (97.5%)
| <sup>224</sup>Th
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| [[Physics:Electron capture|EC]] (2.5%)
| <sup>228</sup>Pa
|-
| rowspan=2|<sup>229</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 137
| rowspan=2|229.0335060(64)
| rowspan=2|57.8(0.5)&nbsp;min
| β<sup>+</sup> (80%)
| <sup>229</sup>Pa
| rowspan=2|(3/2+)
| rowspan=2|
| rowspan=2|
|-
| α (20%)
| <sup>225</sup>Th
|-
| rowspan=3|<sup>230</sup>U
| rowspan=3|
| rowspan=3 style="text-align:right" | 92
| rowspan=3 style="text-align:right" | 138
| rowspan=3|230.0339401(48)
| rowspan=3|20.23(0.02) d
| α
| <sup>226</sup>Th
| rowspan=3|0+
| rowspan=3|
| rowspan=3|
|-
| [[Physics:Spontaneous fission|SF]] ?
| (various)
|-
| [[Physics:Cluster decay|CD]] (4.8×10<sup>−12</sup>%)
| '''<sup>208</sup>Pb'''<br/>'''<sup>22</sup>Ne'''
|-
| rowspan=2|<sup>231</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 139
| rowspan=2|231.0362922(29)
| rowspan=2|4.2(0.1)&nbsp;d
| EC
| <sup>231</sup>Pa
| rowspan=2|5/2+#
| rowspan=2|
| rowspan=2|
|-
| α (.004%)
| <sup>227</sup>Th
|-
| rowspan=4|[[Physics:Uranium-232|<sup>232</sup>U]]
| rowspan=4|
| rowspan=4 style="text-align:right" | 92
| rowspan=4 style="text-align:right" | 140
| rowspan=4|232.0371548(19)
| rowspan=4|68.9(0.4)&nbsp;y
| α
| <sup>228</sup>Th
| rowspan=4|0+
| rowspan=4|
| rowspan=4|
|-
| [[Physics:Cluster decay|CD]] (8.9×10<sup>−10</sup>%)
| '''<sup>208</sup>Pb'''<br/><sup>24</sup>Ne
|-
| SF (10<sup>−12</sup>%)
| (various)
|-
| CD?
| '''<sup>204</sup>Hg'''<br/><sup>28</sup>Mg
|-
| rowspan=4|[[Physics:Uranium-233|<sup>233</sup>U]]
| rowspan=4|
| rowspan=4 style="text-align:right" | 92
| rowspan=4 style="text-align:right" | 141
| rowspan=4|233.0396343(24)
| rowspan=4|1.592(2)×10<sup>5</sup>&nbsp;y
| α
| <sup>229</sup>Th
| rowspan=4|5/2+
| rowspan=4|Trace<ref group=n>Intermediate decay product of [[Physics:Neptunium-237|<sup>237</sup>Np]]</ref>
| rowspan=4|
|-
| CD (≤7.2×10<sup>−11</sup>%)
| <sup>209</sup>Pb<br/><sup>24</sup>Ne
|-
| SF ?
| (various)
|-
| CD ?
| <sup>205</sup>Hg<br/><sup>28</sup>Mg
|-
| rowspan=5|[[Physics:Uranium-234|<sup>234</sup>U]]<ref group="n">Used in [[Physics:Uranium–thorium dating|uranium–thorium dating]]</ref><ref group="n" name="uu">Used in [[Physics:Uranium–uranium dating|uranium–uranium dating]]</ref>
| rowspan=5|Uranium II
| rowspan=5 style="text-align:right" | 92
| rowspan=5 style="text-align:right" | 142
| rowspan=5|234.0409503(12)
| rowspan=5|2.455(6)×10<sup>5</sup>&nbsp;y
| α
| <sup>230</sup>Th
| rowspan=5|0+
| rowspan=5|[0.000054(5)]<ref group="n">Intermediate [[Physics:Decay product|decay product]] of [[Physics:Uranium-238|<sup>238</sup>U]]</ref>
| rowspan=5|0.000050–<br/>0.000059
|-
| SF (1.64×10<sup>−9</sup>%)
| (various)
|-
| CD (1.4×10<sup>−11</sup>%)
| <sup>206</sup>Hg<br/><sup>28</sup>Mg
|-
| CD (≤9×10<sup>−12</sup>%)
| '''<sup>208</sup>Pb'''<br/><sup>26</sup>Ne
|-
| CD (≤9×10<sup>−12</sup>%)
| <sup>210</sup>Pb<br/><sup>24</sup>Ne
|-
| style="text-indent:1em" | <sup>234m</sup>U
|
| colspan="3" style="text-indent:2em" | 1421.257(17)&nbsp;keV=
| 33.5(2.0)&nbsp;ms
| IT
| <sup>234</sup>U
| 6−
|
|
|-
| rowspan=5|[[Physics:Uranium-235|<sup>235</sup>U]]<ref group="n" name="pn">[[Chemistry:Primordial nuclide|Primordial]] [[Physics:Radionuclide|radionuclide]]</ref><ref group="n" name="ul">Used in [[Physics:Uranium–lead dating|Uranium–lead dating]]</ref><ref group="n">Important in nuclear reactors</ref>
| rowspan=5|Actin Uranium<br/>Actino-Uranium
| rowspan=5 style="text-align:right" | 92
| rowspan=5 style="text-align:right" | 143
| rowspan=5|235 0439281(12)
| rowspan=5|7.038(1)×10<sup>8</sup>&nbsp;y
| α
| <sup>231</sup>Th
| rowspan=5|7/2−
| rowspan=5|[0.007204(6)]
| rowspan=5|0.007198–<br/>0.007207
|-
| SF (7×10<sup>−9</sup>%)
| (various)
|-
| CD (8×10<sup>−10</sup>%)
| <sup>215</sup>Pb<br/><sup>20</sup>Ne
|-
| CD (8×10<sup>−10</sup>%)
| <sup>210</sup>Pb<br/><sup>25</sup>Ne
|-
| CD (8×10<sup>−10</sup>%)
| <sup>207</sup>Hg<br/><sup>28</sup>Mg
|-
| style="text-indent:1em" | <sup>235m1</sup>U
|
| colspan="3" style="text-indent:2em" | 0.076737(18)&nbsp;keV
| 25.7(1)&nbsp;m
| IT
| '''''<sup>235</sup>U'''''
| 1/2+
|
|
|-
| style="text-indent:1em" | <sup>235m2</sup>U
|
| colspan="3" style="text-indent:2em" | 2500(300)&nbsp;keV
| 3.6(18)&nbsp;ms
| SF
| (various)
| 
|
|
|-
| rowspan=4|[[Physics:Uranium-236|<sup>236</sup>U]]
| rowspan=4|Thoruranium<ref name="thoruranium">{{cite journal |last1=Trenn |first1=Thaddeus J. |date=1978 |title=Thoruranium (U-236) as the extinct natural parent of thorium: The premature falsification of an essentially correct theory |journal=Annals of Science |volume=35 |issue=6 |pages=581–97 |doi=10.1080/00033797800200441}}</ref>
| rowspan=4 style="text-align:right" | 92
| rowspan=4 style="text-align:right" | 144
| rowspan=4|236.0455661(12)
| rowspan=4|2.342(3)×10<sup>7</sup>&nbsp;y
| α
| '''''<sup>232</sup>Th'''''
| rowspan=4|0+
| rowspan=4|Trace<ref group=n>Intermediate decay product of [[Physics:Plutonium-244|<sup>244</sup>Pu]], also produced by [[Physics:Neutron capture|neutron capture]] of <sup>235</sup>U</ref>
| rowspan=4|
|-
| SF (9.6×10<sup>−8</sup>%)
| (various)
|-
| CD (≤2.0×10<sup>−11</sup>%)<ref name="CD">{{cite journal |last1=Bonetti |first1=R. |last2=Guglielmetti |first2=A. |year=2007 |title=Cluster radioactivity: an overview after twenty years |url=http://www.rrp.infim.ro/2007_59_2/10_bonetti.pdf |archive-url=https://web.archive.org/web/20160919014152/http://www.rrp.infim.ro/2007_59_2/10_bonetti.pdf |archive-date=19 September 2016 |journal=Romanian Reports in Physics |volume=59 |pages=301–310}}</ref>
| <sup>208</sup>Hg<br/><sup>28</sup>Mg
|-
| CD (≤2.0×10<sup>−11</sup>%)<ref name="CD"/>
| <sup>206</sup>Hg<br/><sup>30</sup>Mg
|-
| style="text-indent:1em" | <sup>236m1</sup>U
|
| colspan="3" style="text-indent:2em" | 1052.5(6)&nbsp;keV
| 100(4)&nbsp;ns
| IT
| <sup>236</sup>U
| 4−
|
|
|-
| rowspan=2 style="text-indent:1em" | <sup>236m2</sup>U
| rowspan=2|
| rowspan=2 colspan="3" style="text-indent:2em" | 2750(3)&nbsp;keV
| rowspan=2|120(2)&nbsp;ns
| IT (87%)
| <sup>236</sup>U
| rowspan=2|(0+)
| rowspan=2|
| rowspan=2|
|-
| SF (13%)
| (various)
|-
| <sup>237</sup>U
|
| style="text-align:right" | 92
| style="text-align:right" | 145
| 237.0487283(13)
| 6.752(2)&nbsp;d
| β<sup>−</sup>
| <sup>237</sup>Np
| 1/2+
| Trace<ref group=n>Neutron capture product, parent of trace quantities of [[Physics:Neptunium-237|<sup>237</sup>Np]]</ref>
|
|-
| style="text-indent:1em" | <sup>237m</sup>U
|
| colspan="3" style="text-indent:2em" | 274.0(10)&nbsp;keV
| 155(6)&nbsp;ns
| IT
| <sup>237</sup>U
| 7/2−
|
|
|-
| rowspan=3|[[Physics:Uranium-238|<sup>238</sup>U]]<ref group="n" name="uu" /><ref group="n" name="pn" /><ref group="n" name="ul" />
| rowspan=3|Uranium I
| rowspan=3 style="text-align:right" | 92
| rowspan=3 style="text-align:right" | 146
| rowspan=3|238.0507869(16)
| rowspan=3|4.468(3)×10<sup>9</sup>&nbsp;y
| α
| <sup>234</sup>Th
| rowspan=3|0+
| rowspan=3|[0.992742(10)]
| rowspan=3|0.992739–<br/>0.992752
|-
| SF (5.44×10<sup>−5</sup>%)
| (various)
|-
| [[Physics:Double beta decay|β<sup>−</sup>β<sup>−</sup>]] (2.2×10<sup>−10</sup>%)
| <sup>238</sup>Pu
|-
| rowspan=2 style="text-indent:1em" | <sup>238m</sup>U
| rowspan=2|
| rowspan=2 colspan="3" style="text-indent:2em" | 2557.9(5)&nbsp;keV
| rowspan=2|280(6)&nbsp;ns
| IT (97.4%)
| '''''<sup>238</sup>U'''''
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| SF (2.6%)
| (various)
|-
| <sup>239</sup>U
|
| style="text-align:right" | 92
| style="text-align:right" | 147
| 239.0542920(16)
| 23.45(0.02)&nbsp;min
| β<sup>−</sup>
| <sup>239</sup>Np
| 5/2+
|
|
|-
| style="text-indent:1em" | <sup>239m1</sup>U
|
| colspan="3" style="text-indent:2em" | 133.7991(10)&nbsp;keV
| 780(40)&nbsp;ns
| IT
| <sup>239</sup>U
| 1/2+
|
|
|-
| rowspan=2 style="text-indent:1em" | <sup>239m2</sup>U
| rowspan=2|
| rowspan=2 colspan="3" style="text-indent:2em" | 2500(900)#&nbsp;keV
| rowspan=2|>250&nbsp;ns
| SF?
| (various)
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| IT?
| <sup>239</sup>U
|-
| rowspan=2|<sup>240</sup>U
| rowspan=2|
| rowspan=2 style="text-align:right" | 92
| rowspan=2 style="text-align:right" | 148
| rowspan=2|240.0565924(27)
| rowspan=2|14.1(0.1)&nbsp;h
| β<sup>−</sup>
| <sup>240</sup>Np
| rowspan=2|0+
| rowspan=2|Trace<ref group=n>Intermediate decay product of <sup>244</sup>Pu</ref>
| rowspan=2|
|-
| α?
| <sup>236</sup>Th
|-
| <sup>241</sup>U<ref name=U241>{{cite journal |title = Discovery of New Isotope <sup>241</sup>U and Systematic High-Precision Atomic Mass Measurements of Neutron-Rich Pa-Pu Nuclei Produced via Multinucleon Transfer Reactions |author1= Niwase, T. |author2=Watanabe, Y. X. |author3=Hirayama, Y. |author4=Mukai, M. |author5=Schury, P. |author6=Andreyev, A. N. |author7=Hashimoto, T. |author8=Iimura, S. |author9=Ishiyama, H. |author10=Ito, Y. |author11=Jeong, S. C. |author12=Kaji, D. |author13=Kimura, S. |author14=Miyatake, H. |author15=Morimoto, K. |author16=Moon, J.-Y. |author17=Oyaizu, M. |author18=Rosenbusch, M. |author19=Taniguchi, A. |author20=Wada, M. |display-authors=3  |journal = Physical Review Letters |volume = 130 |issue = 13 |pages = 132502-1–132502-6 |year = 2023 |doi = 10.1103/PhysRevLett.130.132502|pmid= 37067317 |s2cid= 257976576 |url= https://eprints.whiterose.ac.uk/197980/1/PhysRevLett.130.132502.pdf }}</ref>
|
| style="text-align:right" | 92
| style="text-align:right" | 149
| 241.06031(5)<!--WP:CALC (unit conversion and error propagation) from the Dalton mass and the mass excess in the paper-->
| ~40&nbsp;min<ref name="u241">{{Cite news |last=Mukunth |first=Vasudevan |date=2023-04-05 |title=In pursuit of a 'magic number', physicists discover new uranium isotope |language=en-IN |work=The Hindu |url=https://www.thehindu.com/sci-tech/science/in-pursuit-of-a-magic-number-physicists-discover-new-uranium-isotope/article66699249.ece |access-date=2023-04-12 |issn=0971-751X}}</ref><ref>{{Cite news |last=Yirka |first=Bob  |date=April 5, 2023 |title=Previously unknown isotope of uranium discovered |language=en |work=Phys.org |url=https://phys.org/news/2023-04-previously-unknown-isotope-uranium.html |access-date=2023-04-12}}</ref>
| β<sup>−</sup>
| <sup>241</sup>Np
| 7/2+#
|
|-->
|-
| <sup>242</sup>U
|
| style="text-align:right" | 92
| style="text-align:right" | 150
| 242.06296(10)<!--WP:CALC (unit conversion and error propagation) from the Dalton mass and the mass excess in the paper--><ref name="u241"/>
| 16.8(0.5)&nbsp;min
| β<sup>−</sup>
| <sup>242</sup>Np
| 0+
|
|
{{Isotopes table/footer}}

==Actinides vs fission products==
{{Actinidesvsfissionproducts}}
{{Clear}}

==Uranium-214==
{{anchor|Uranium-214}}
Uranium-214 is the lightest known isotope of uranium. It was discovered at the Spectrometer for Heavy Atoms and Nuclear Structure (SHANS) at the Heavy Ion Research Facility in Lanzhou, {{wipe|China}} in 2021, produced by firing argon-36 at tungsten-182. It undergoes alpha decay with a half-life of {{val|0.5|u=ms}}.<ref>{{cite web |title=Physicists Discover New Uranium Isotope: Uranium-214 |date=14 May 2021 |url=http://www.sci-news.com/physics/uranium-214-09658.html |publisher=Sci-News.com |access-date=15 May 2021}}</ref><ref>{{cite journal |title=New α -Emitting Isotope 214 U and Abnormal Enhancement of α -Particle Clustering in Lightest Uranium Isotopes |year=2021 |url=https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.152502 |doi=10.1103/PhysRevLett.126.152502 |access-date=15 May 2021|last1=Zhang |first1=Z. Y. |last2=Yang |first2=H. B. |last3=Huang |first3=M. H. |last4=Gan |first4=Z. G. |last5=Yuan |first5=C. X. |last6=Qi |first6=C. |last7=Andreyev |first7=A. N. |last8=Liu |first8=M. L. |last9=Ma |first9=L. |last10=Zhang |first10=M. M. |last11=Tian |first11=Y. L. |last12=Wang |first12=Y. S. |last13=Wang |first13=J. G. |last14=Yang |first14=C. L. |last15=Li |first15=G. S. |last16=Qiang |first16=Y. H. |last17=Yang |first17=W. Q. |last18=Chen |first18=R. F. |last19=Zhang |first19=H. B. |last20=Lu |first20=Z. W. |last21=Xu |first21=X. X. |last22=Duan |first22=L. M. |last23=Yang |first23=H. R. |last24=Huang |first24=W. X. |last25=Liu |first25=Z. |last26=Zhou |first26=X. H. |last27=Zhang |first27=Y. H. |last28=Xu |first28=H. S. |last29=Wang |first29=N. |last30=Zhou |first30=H. B. |journal=Physical Review Letters |volume=126 |issue=15 |page=152502 |pmid=33929212 |arxiv=2101.06023 |bibcode=2021PhRvL.126o2502Z |s2cid=231627674 |display-authors=1 }}</ref><ref>{{cite web |title=Lightest-known form of uranium created |date=3 May 2021 |url=https://www.livescience.com/lightest-uranium-isotope-discovered.html |publisher=Live Science |access-date=15 May 2021}}</ref><ref>{{cite web |title=Physicists have created a new and extremely rare kind of uranium |url=https://www.newscientist.com/article/2274847-physicists-have-created-a-new-and-extremely-rare-kind-of-uranium/ |publisher=New Scientist |access-date=15 May 2021}}</ref>

==Uranium-232==
{{main|Physics:Uranium-232}}

Uranium-232 has a half-life of 68.9 years and is a side product in the thorium cycle. It has been cited as an obstacle to nuclear proliferation using <sup>233</sup>U as the fissile material, because the intense gamma radiation emitted by [[Physics:Thallium-208|<sup>208</sup>Tl]] (a daughter of <sup>232</sup>U, produced relatively quickly) makes the <sup>233</sup>U contaminated with it more difficult to handle. Uranium-232 is a rare example of an [[Physics:Even and odd atomic nuclei|even-even isotope]] that is fissile with both thermal and fast neutrons.<ref>{{cite web |url=https://www.nuclear-power.net/nuclear-power-plant/nuclear-fuel/uranium/uranium-232/ |title=Uranium 232 |publisher=Nuclear Power |access-date=3 June 2019 |url-status=live |archive-url=https://web.archive.org/web/20190226212021/https://www.nuclear-power.net/nuclear-power-plant/nuclear-fuel/uranium/uranium-232/ |archive-date=26 February 2019}}</ref><ref>{{cite web |url=http://atom.kaeri.re.kr/nuchart/getEvaf.jsp?mat=9219&lib=endfb7.1 |title=INCIDENT NEUTRON DATA |date=2011-12-14 |website=atom.kaeri.re.kr}}</ref>

==Uranium-233==
{{Main|Physics:Uranium-233}}

Uranium-233 is a fissile isotope of uranium that is bred from [[Physics:Thorium-232|thorium-232]] as part of the thorium fuel cycle. Uranium-233 was investigated for use in nuclear weapons and as a reactor fuel. It was occasionally tested but never deployed in nuclear weapons and has not been used commercially as a nuclear fuel.<ref name="Forsburg">{{cite journal|author1=C. W. Forsburg|author2=L. C. Lewis|title=Uses For Uranium-233: What Should Be Kept for Future Needs?|publisher=Oak Ridge National Laboratory|journal=Ornl-6952|date=1999-09-24|url=http://moltensalt.org/references/static/downloads/pdf/ORNL-6952.pdf}}</ref> It has been used successfully in experimental nuclear reactors and has been proposed for much wider use as a nuclear fuel. It has a half-life of around 160,000 years.

Uranium-233 is produced by the neutron irradiation of thorium-232. When thorium-232 absorbs a [[Physics:Neutron|neutron]], it becomes [[Physics:Thorium-233|thorium-233]], which has a half-life of only 22 minutes. Thorium-233 decays into [[Physics:Protactinium-233|protactinium-233]] through [[Physics:Beta decay|beta decay]]. Protactinium-233 has a half-life of 27 days and beta decays into uranium-233; some proposed molten salt reactor designs attempt to physically isolate the protactinium from further neutron capture before beta decay can occur.

Uranium-233 usually fissions on neutron absorption but sometimes retains the neutron, becoming [[Physics:Uranium-234|uranium-234]]. The capture-to-fission ratio is smaller than the other two major fissile fuels, [[Physics:Uranium-235|uranium-235]] and [[Physics:Plutonium-239|plutonium-239]]; it is also lower than that of short-lived [[Physics:Plutonium-241|plutonium-241]], but bested by very difficult-to-produce [[Physics:Neptunium-236|neptunium-236]].

==Uranium-234==
{{Main|Physics:Uranium-234}}

Uranium-234 is an isotope of uranium. In natural uranium and in uranium ore, <sup>234</sup>U occurs as an indirect decay product of uranium-238, but it makes up only 0.0055% (55 parts per million) of the raw [[Chemistry:Uranium|uranium]] because its [[Physics:Half-life|half-life]] of just 245,500 years is only about 1/18,000 as long as that of [[Physics:Uranium-238|<sup>238</sup>U]]. The path of production of <sup>234</sup>U via nuclear decay is as follows: <sup>238</sup>U nuclei emit an [[Physics:Alpha particle|alpha particle]] to become [[Physics:Thorium-234|thorium-234]]. Next, with a short [[Physics:Half-life|half-life]], a <sup>234</sup>Th nucleus emits a [[Physics:Beta particle|beta particle]] to become [[Physics:Protactinium-234|protactinium-234]]. Finally, <sup>234</sup>Pa nuclei each emit another beta particle to become <sup>234</sup>U nuclei.{{NUBASE2016|ref}}<ref name="HCWR212" />

<sup>234</sup>U nuclei usually last for hundreds of thousands of years, but then they decay by alpha emission to [[Physics:Thorium-230|thorium-230]], except for the small percentage of nuclei that undergo [[Physics:Spontaneous fission|spontaneous fission]].

Extraction of rather small amounts of <sup>234</sup>U from natural uranium would be feasible using [[Physics:Isotope separation|isotope separation]], similar to that used for regular uranium-enrichment. However, there is no real demand in [[Chemistry:Chemistry|chemistry]], [[Physics:Physics|physics]], or engineering for isolating <sup>234</sup>U. Very small pure samples of <sup>234</sup>U can be extracted via the chemical ion-exchange process—from samples of [[Physics:Plutonium-238|plutonium-238]] that have been aged somewhat to allow some decay to <sup>234</sup>U via alpha emission.

[[Physics:Enriched uranium|Enriched uranium]] contains more <sup>234</sup>U than natural uranium as a byproduct of the uranium enrichment process aimed at obtaining [[Physics:Uranium-235|uranium-235]], which concentrates lighter isotopes even more strongly than it does <sup>235</sup>U. The increased percentage of <sup>234</sup>U in enriched natural uranium is acceptable in current nuclear reactors, but (re-enriched) [[Physics:Reprocessed uranium|reprocessed uranium]] might contain even higher fractions of <sup>234</sup>U, which is undesirable.<ref name="RpU">{{cite conference |publisher=[[Organization:International Atomic Energy Agency|International Atomic Energy Agency]] |date=2009 |isbn=978-92-0-157109-0 |issn=1684-2073 |location=Vienna |title=Use of Reprocessed Uranium |journal=Technical Document |url=https://www-pub.iaea.org/MTCD/publications/PDF/TE_1630_CD/PDF/IAEA-TECDOC-1630.pdf}}</ref> This is because <sup>234</sup>U is not fissile, and tends to absorb slow neutrons in a [[Physics:Nuclear reactor|nuclear reactor]]—becoming <sup>235</sup>U.<ref name="HCWR212">{{cite book |editor-last=Ronen |editor-first=Y. |publisher=CRC Press |title=High converting water reactors |year=1990 |isbn=0-8493-6081-1 |lccn=89-25332 |page=212}}</ref><ref name="RpU" />

<sup>234</sup>U has a [[Physics:Neutron capture|neutron capture]] cross section of about 100 [[Physics:Barn (unit)|barns]] for thermal neutrons, and about 700 barns for its resonance integral—the average over neutrons having various intermediate energies. In a nuclear reactor, non-fissile isotopes capture a neutron breeding fissile isotopes. <sup>234</sup>U is converted to <sup>235</sup>U more easily and therefore at a greater rate than [[Physics:Uranium-238|uranium-238]] is to [[Physics:Plutonium-239|plutonium-239]] (via [[Physics:Neptunium-239|neptunium-239]]), because <sup>238</sup>U has a much smaller neutron-capture [[Physics:Cross section|cross section]] of just 2.7 barns.

==Uranium-235==
{{Main|Physics:Uranium-235}}

Uranium-235 is an [[Physics:Isotope|isotope]] of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope [[Physics:Uranium-238|uranium-238]], it is fissile, i.e., it can sustain a [[Physics:Nuclear fission|fission]] [[Philosophy:Chain reaction|chain reaction]]. It is the only fissile isotope that is a [[Chemistry:Primordial nuclide|primordial nuclide]] or found in significant quantity in nature.

Uranium-235 has a [[Physics:Half-life|half-life]] of 703.8 million years. It was discovered in 1935 by [[Biography:Arthur Jeffrey Dempster|Arthur Jeffrey Dempster]]. Its (fission) nuclear cross section for slow thermal neutron is about 504.81 [[Physics:Barn (unit)|barn]]s. For fast neutrons it is on the order of 1 barn. At thermal energy levels, about 5 of 6 neutron absorptions result in fission and 1 of 6 result in neutron capture forming [[Physics:Uranium-236|uranium-236]].<ref>{{cite journal|author1=B. C. Diven |author2=J. Terrell |author3=A. Hemmendinger|title=Capture-to-Fission Ratios for Fast Neutrons in U235|journal=Physical Review Letters|date=1 January 1958|doi=10.1103/PhysRev.109.144|volume=109|issue=1 |pages=144–150|bibcode=1958PhRv..109..144D}}</ref> The fission-to-capture ratio improves for faster neutrons.

==Uranium-236==
{{Main|Physics:Uranium-236}}

Uranium-236 is an [[Physics:Isotope|isotope]] of [[Chemistry:Uranium|uranium]] with a half-life of about 23 million years that is neither fissile with thermal neutrons, nor very good fertile material, but is generally considered a nuisance and long-lived [[Physics:Radioactive waste|radioactive waste]]. It is found in spent [[Physics:Nuclear fuel|nuclear fuel]] and in the reprocessed uranium made from spent nuclear fuel.

==Uranium-237==
<!--
{{Main|Physics:Uranium-237}}
-->Uranium-237 is an isotope of [[Chemistry:Uranium|uranium]]. It has a half-life of about 6.75(1) days. It decays into [[Physics:Neptunium-237|neptunium-237]] by [[Physics:Beta decay|beta decay]]. It was discovered by Japanese physicist Yoshio Nishina in 1940, who in a near-miss discovery, inferred the creation of element 93, but was unable to isolate the then-unknown element or measure its decay properties.<ref>{{Cite journal |last=Ikeda |first=Nagao |date=July 25, 2011 |title=The discoveries of uranium 237 and symmetric fission — From the archival papers of Nishina and Kimura |journal=Proceedings of the Japan Academy. Series B, Physical and Biological Sciences |volume=87 |issue=7 |pages=371–376 |doi=10.2183/pjab.87.371 |pmid=21785255 |pmc=3171289 }}</ref>

==Uranium-238==
{{Main|Physics:Uranium-238}}

Uranium-238 (<sup>238</sup>U or U-238) is the most common [[Physics:Isotope|isotope]] of [[Chemistry:Uranium|uranium]] found in nature. It is not fissile, but is a fertile material: it can capture a slow [[Physics:Neutron|neutron]] and after two beta decays become fissile [[Physics:Plutonium-239|plutonium-239]]. Uranium-238 is fissionable by fast neutrons, but cannot support a chain reaction because inelastic scattering reduces neutron energy below the range where fast fission of one or more next-generation nuclei is probable. Doppler broadening of <sup>238</sup>U's neutron absorption resonances, increasing absorption as fuel temperature increases, is also an essential negative feedback mechanism for reactor control.

Around 99.284% of natural uranium is uranium-238, which has a half-life of 1.41×10<sup>17</sup> seconds (4.468×10<sup>9</sup> years, or 4.468 billion years). Depleted uranium has an even higher concentration of the <sup>238</sup>U isotope, and even low-enriched uranium (LEU), while having a higher proportion of the uranium-235 isotope (in comparison to depleted uranium), is still mostly <sup>238</sup>U. Reprocessed uranium is also mainly <sup>238</sup>U, with about as much uranium-235 as natural uranium, a comparable proportion of uranium-236, and much smaller amounts of other isotopes of uranium such as [[Physics:Uranium-234|uranium-234]], [[Physics:Uranium-233|uranium-233]], and [[Physics:Uranium-232|uranium-232]].

==Uranium-239==

'''Uranium-239''' is an isotope of uranium. It is usually produced by exposing [[Physics:Uranium-238|<sup>238</sup>U]] to [[Physics:Neutron radiation|neutron radiation]] in a nuclear reactor. <sup>239</sup>U has a half-life of about 23.45 minutes and decays into [[Physics:Neptunium-239|neptunium-239]] through [[Physics:Beta decay|beta decay]], with a total decay energy of about 1.29&nbsp;MeV.<ref>''CRC Handbook of Chemistry and Physics'', 57th Ed. p. B-345</ref><!-- assume decay energy 1.28&nbsp;MeV and max beta energy 1.29&nbsp;MeV is a transposition error--> The most common gamma decay at 74.660&nbsp;keV accounts for the difference in the two major channels of beta emission energy, at 1.28 and 1.21&nbsp;MeV.<ref>''CRC Handbook of Chemistry and Physics'', 57th Ed. p. B-423</ref>

<sup>239</sup>Np further decays to [[Physics:Plutonium-239|plutonium-239]] also through [[Physics:Beta decay|beta decay]] with a half-life of about 2.356 days, in a second important step that ultimately produces fissile <sup>239</sup>Pu (used in weapons and for nuclear power), from <sup>238</sup>U in reactors.

== Uranium-241 ==
'''Uranium-241''' is an isotope of uranium. In 2023, in a paper published in ''[[Physics:Physical Review Letters|Physical Review Letters]]'', a group of researchers based in Korea reported that they had found uranium-241 in an experiment involving <sup>238</sup>U+<sup>198</sup>Pt multinucleon transfer reactions.<ref name="phys.org-241U">{{Cite web |last1=Yirka |first1=Bob |last2=Phys.org |title=Previously unknown isotope of uranium discovered |url=https://phys.org/news/2023-04-previously-unknown-isotope-uranium.html |access-date=2023-04-10 |website=phys.org |language=en}}</ref><ref>{{Cite journal |last1=Niwase |first1=T. |last2=Watanabe |first2=Y. X. |last3=Hirayama |first3=Y. |last4=Mukai |first4=M. |last5=Schury |first5=P. |last6=Andreyev |first6=A. N. |last7=Hashimoto |first7=T. |last8=Iimura |first8=S. |last9=Ishiyama |first9=H. |last10=Ito |first10=Y. |last11=Jeong |first11=S. C. |last12=Kaji |first12=D. |last13=Kimura |first13=S. |last14=Miyatake |first14=H. |last15=Morimoto |first15=K. |date=2023-03-31 |title=Discovery of New Isotope $^{241}\mathrm{U}$ and Systematic High-Precision Atomic Mass Measurements of Neutron-Rich Pa-Pu Nuclei Produced via Multinucleon Transfer Reactions |url=https://link.aps.org/doi/10.1103/PhysRevLett.130.132502 |journal=Physical Review Letters |volume=130 |issue=13 |pages=132502 |doi=10.1103/PhysRevLett.130.132502|pmid=37067317 |s2cid=257976576 }}</ref>
Its half-life is approximately 40&nbsp;minutes.<ref name="phys.org-241U"/>

==References==
{{Reflist}}

{{Navbox element isotopes}}

[[Category:Isotopes of uranium| ]]
[[Category:Uranium]]
[[Category:Lists of isotopes by element|Uranium]]

{{Sourceattribution|Isotopes of uranium}}