Editing Decay chain (section)

=== Actinium series ===
The 4n+3 chain of [[uranium-235]] is commonly called the "actinium series" or "actinium cascade". Beginning with the naturally-occurring isotope uranium-235, this decay series includes the following elements:  actinium, [[astatine]], [[bismuth]], [[francium]], [[lead]], [[polonium]], [[protactinium]], radium, radon, [[thallium]], and [[thorium]]. All are present, at least transiently, in any sample containing uranium-235, whether metal, compound, ore, or mineral. This series terminates with the stable isotope [[lead-207]].
[[Image:Decay Chain of Actinium.svg|thumb|right|300px|alt=Actinium series|([[commons:File:Decay scheme U235.png|More detailed graphic]])]]

In the early Solar System this chain went back to <sup>247</sup>Cm. This manifests itself today as variations in <sup>235</sup>U/<sup>238</sup>U ratios, since [[curium]] and uranium have noticeably different chemistries and would have separated differently.<ref name=Davis/><ref>{{cite journal |last1=Tsaletka |first1=R. |last2=Lapitskii |first2=A. V. |date=1960 |title=Occurrence of the Transuranium Elements in Nature |url=https://www.russchemrev.org/RCR1264pdf |journal=Russian Chemical Reviews |volume=29 |issue=12 |pages=684–689 |doi= 10.1070/RC1960v029n12ABEH001264|bibcode=1960RuCRv..29..684T |access-date=20 January 2024}}</ref>

The total energy released from uranium-235 to lead-207, including the energy lost to neutrinos, is 46.4&nbsp;MeV.

{| class="wikitable" style="margin:auto; text-align:center;"
!rowspan=2|Nuclide
!colspan=2|Historic name
!rowspan=2|Decay mode
!rowspan=2|Half-life<br />(''a'' = years)
!rowspan=2|Energy released<br/>MeV
!rowspan=2|Decay<br/>product
|-
!Short!!Long
|-
| [[Californium-251|<sup>251</sup>Cf]]
| 
| 
| [[alpha decay|α]]
| 900.6&nbsp;a
| 6.176
| <sup>247</sup>Cm
|-
|[[Curium-247|<sup>247</sup>Cm]]
|
|
|α
|1.56×10<sup>7</sup> a
|5.353
|<sup>243</sup>Pu
|-
|[[Plutonium-243|<sup>243</sup>Pu]]
|
| 
| [[beta decay|β<sup>&minus;</sup>]]
| 4.95556&nbsp;h
| 0.579
| <sup>243</sup>Am
|-
| [[Americium-243|<sup>243</sup>Am]]
| 
| 
| α
| 7388&nbsp;a
| 5.439
| <sup>239</sup>Np
|-
| [[Neptunium-239|<sup>239</sup>Np]]
| 
| 
| β<sup>&minus;</sup>
| 2.3565&nbsp;d
| 0.723
| <sup>239</sup>Pu
|-
| [[Plutonium-239|<sup>239</sup>Pu]]
| 
| 
| α
| align="center"| 2.41×10<sup>4</sup> a
| align="center"| 5.244
| align="center"| <sup>235</sup>U
|-
| align="center"| <sup>235</sup>U
| align="center"| AcU
| align="center"| Actino-uranium
| align="center"|  α
| align="center"| 7.04×10<sup>8</sup> a
| align="center"| 4.678
| align="center"| [[Thorium-231|<sup>231</sup>Th]]
|-
| align="center"| <sup>231</sup>Th
| align="center"| UY
| align="center"| Uranium Y
| align="center"| β<sup>−</sup>
| align="center"| 25.52 h
| align="center"| 0.391
| align="center"| [[Protactinium-231|<sup>231</sup>Pa]]
|-
| align="center"| <sup>231</sup>Pa
| align="center"| Pa
| align="center"| Protoactinium
| align="center"| α
| align="center"| 32760 a
| align="center"| 5.150
| align="center"| [[Actinium-227|<sup>227</sup>Ac]]
|-
| align="center"| <sup>227</sup>Ac
| align="center"| Ac
| align="center"| Actinium
| align="center"| β<sup>−</sup> 98.62% <br /> α 1.38%
| align="center"| 21.772 a
| align="center"| 0.045 <br /> 5.042
| align="center"| [[Thorium-227|<sup>227</sup>Th]] <br /> [[Francium-223|<sup>223</sup>Fr]]
|-
| align="center"| <sup>227</sup>Th
| align="center"| RdAc
| align="center"| Radioactinium
| align="center"|  α
| align="center"| 18.68 d
| align="center"| 6.147
| align="center"| [[Radium-223|<sup>223</sup>Ra]]
|-
| align="center"| <sup>223</sup>Fr
| align="center"| AcK
| align="center"| Actinium K
| align="center"|  β<sup>−</sup> 99.994% <br /> α 0.006%
| align="center"| 22.00 min
| align="center"| 1.149 <br /> 5.340
| align="center"| <sup>223</sup>Ra <br /> [[Astatine-219|<sup>219</sup>At]]
|-
| align="center"| <sup>223</sup>Ra
| align="center"| AcX
| align="center"| Actinium X
| align="center"|  α
| align="center"| 11.43 d
| align="center"| 5.979
| align="center"| [[Radon-219|<sup>219</sup>Rn]]
|-
| align="center"| <sup>219</sup>At
| align="center"|
| align="center"|
| align="center"|  α 97.00% <br /> β<sup>−</sup> 3.00%
| align="center"| 56 s
| align="center"| 6.275 <br /> 1.700
| align="center"| [[Bismuth-215|<sup>215</sup>Bi]] <br /> <sup>219</sup>Rn
|-
| align="center"| <sup>219</sup>Rn
| align="center"| An
| align="center"| Actinon,<br />Actinium Emanation
| align="center"|  α
| align="center"| 3.96 s
| align="center"| 6.946
| align="center"| [[Polonium-215|<sup>215</sup>Po]]
|-
| align="center"| <sup>215</sup>Bi
| align="center"|
| align="center"|
| align="center"|  β<sup>−</sup>
| align="center"| 7.6 min
| align="center"| 2.250  	
| align="center"| <sup>215</sup>Po
|-
| align="center"| <sup>215</sup>Po
| align="center"| AcA
| align="center"| Actinium A
| align="center"|  α 99.99977% <br />  β<sup>−</sup> 0.00023%
| align="center"| 1.781 ms
| align="center"| 7.527 <br /> 0.715
| align="center"| [[Lead-211|<sup>211</sup>Pb]] <br /> [[Astatine-215|<sup>215</sup>At]]
|-
| align="center"| <sup>215</sup>At
| align="center"|
| align="center"|
| align="center"|  α
| align="center"| 0.1 ms
| align="center"| 8.178
| align="center"| [[Bismuth-211|<sup>211</sup>Bi]]
|-
| align="center"| <sup>211</sup>Pb
| align="center"| AcB
| align="center"| Actinium B
| align="center"|  β<sup>−</sup>
| align="center"| 36.1 min
| align="center"| 1.367
| align="center"| <sup>211</sup>Bi
|-
| align="center"| <sup>211</sup>Bi
| align="center"| AcC
| align="center"| Actinium C
| align="center"|  α 99.724% <br />  β<sup>−</sup> 0.276%
| align="center"| 2.14 min
| align="center"| 6.751 <br /> 0.575
| align="center"| [[Thallium-207|<sup>207</sup>Tl]] <br /> [[Polonium-211|<sup>211</sup>Po]]
|-
| align="center"| <sup>211</sup>Po
| align="center"| AcC'
| align="center"| Actinium C'
| align="center"|  α
| align="center"| 516 ms
| align="center"| 7.595
| align="center"| [[Lead-207|<sup>207</sup>Pb]]
|-
| align="center"| <sup>207</sup>Tl
| align="center"| AcC"
| align="center"| Actinium C"
| align="center"| β<sup>−</sup>
| align="center"| 4.77 min
| align="center"| 1.418
| align="center"| <sup>207</sup>Pb
|-
| align="center"| <sup>207</sup>Pb
| align="center"| AcD
| align="center"| Actinium D
| align="center"| .
| align="center"| stable
| align="center"| .
| align="center"| .
|}