Isotopes of fermium: Difference between revisions
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! <br />isotopic mass (u)<br /> |
! <br />isotopic mass (u)<br /> |
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! rowspan="2" | half-life |
! rowspan="2" | half-life |
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! rowspan="2" | decay<br>mode(s)<ref>http://www.nucleonica.net/unc.aspx</ref><ref group="n">Abbreviations:<br>EC: [[Electron capture]]<br>IT: [[Isomeric transition]]<br>SF: [[Spontaneous fission]]</ref> |
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! rowspan="2" | daughter<br>isotope(s) |
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! rowspan="2" | nuclear<br />spin |
! rowspan="2" | nuclear<br />spin |
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|- |
|- |
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! colspan="3" | excitation energy |
! colspan="3" | excitation energy |
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|- |
|- |
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| <sup>242</sup>Fm |
| rowspan=2|<sup>242</sup>Fm |
||
| style="text-align:right" | 100 |
| rowspan=2 style="text-align:right" | 100 |
||
| style="text-align:right" | 142 |
| rowspan=2 style="text-align:right" | 142 |
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| 242.07343(43)# |
| rowspan=2|242.07343(43)# |
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| 0.8(2) ms |
| rowspan=2|0.8(2) ms |
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| [[Spontaneous fission|SF]] |
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| 0+ |
|||
| (various) |
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| rowspan=2|0+ |
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|- |
|- |
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| [[alpha decay|α]] (rare) |
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| <sup>243</sup>Fm |
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| <sup>238</sup>Cf |
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| style="text-align:right" | 100 |
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| style="text-align:right" | 143 |
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| 243.07435(23)# |
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| 210(60) ms<br>[0.18(+8-4) s] |
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| 7/2-# |
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|- |
|- |
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| <sup> |
| rowspan=3|<sup>243</sup>Fm |
||
| style="text-align:right" | 100 |
| rowspan=3 style="text-align:right" | 100 |
||
| style="text-align:right" | |
| rowspan=3 style="text-align:right" | 143 |
||
| |
| rowspan=3|243.07435(23)# |
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| rowspan=3|210(60) ms<br>[0.18(+8-4) s] |
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| 3.3(5) ms |
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| α (60%) |
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| 0+ |
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| <sup>239</sup>Cf |
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| rowspan=3|7/2-# |
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|- |
|- |
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| <sup> |
| β<sup>+</sup> (40%) |
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| <sup>239</sup>Es |
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| style="text-align:right" | 100 |
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| style="text-align:right" | 145 |
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| 245.07539(30)# |
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| 4.2(13) s |
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| 1/2+# |
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|- |
|- |
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| SF (.57%) |
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| <sup>246</sup>Fm |
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| (various) |
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| style="text-align:right" | 100 |
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| style="text-align:right" | 146 |
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| 246.07530(4) |
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| 1.1(2) s |
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| 0+ |
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|- |
|- |
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| <sup> |
| rowspan=2|<sup>244</sup>Fm |
||
| style="text-align:right" | 100 |
| rowspan=2 style="text-align:right" | 100 |
||
| style="text-align:right" | |
| rowspan=2 style="text-align:right" | 144 |
||
| |
| rowspan=2|244.07408(30)# |
||
| |
| rowspan=2|3.3(5) ms |
||
| ( |
| SF (99%) |
||
| (various) |
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| rowspan=2|0+ |
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|- |
|- |
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| α (1%) |
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| <sup>248</sup>Fm |
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| <sup>240</sup>Cf |
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| style="text-align:right" | 100 |
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| style="text-align:right" | 148 |
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| 248.077195(13) |
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| 36(2) s |
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| 0+ |
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|- |
|- |
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| <sup> |
| rowspan=3|<sup>245</sup>Fm |
||
| style="text-align:right" | 100 |
| rowspan=3 style="text-align:right" | 100 |
||
| style="text-align:right" | |
| rowspan=3 style="text-align:right" | 145 |
||
| |
| rowspan=3|245.07539(30)# |
||
| |
| rowspan=3|4.2(13) s |
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| (7 |
| α (95.7%) |
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| <sup>241</sup>Cf |
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| rowspan=3|1/2+# |
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|- |
|- |
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| <sup> |
| β<sup>+</sup> (4.2%) |
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| <sup>241</sup>Es |
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| style="text-align:right" | 100 |
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|- |
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| style="text-align:right" | 150 |
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| |
| SF (.13%) |
||
| |
| (various) |
||
| |
|- |
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| rowspan=4|<sup>246</sup>Fm |
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| rowspan=4 style="text-align:right" | 100 |
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| rowspan=4 style="text-align:right" | 146 |
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| rowspan=4|246.07530(4) |
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| rowspan=4|1.1(2) s |
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| α (85%) |
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| <sup>242</sup>Cf |
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| rowspan=4|0+ |
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|- |
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| β<sup>+</sup> (10%) |
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| <sup>246</sup>Es |
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|- |
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| β<sup>+</sup>, SF (10%) |
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| (various) |
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|- |
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| SF (4.5%) |
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| (various) |
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|- |
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| rowspan=2|<sup>247</sup>Fm |
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| rowspan=2 style="text-align:right" | 100 |
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| rowspan=2 style="text-align:right" | 147 |
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| rowspan=2|247.07685(15)# |
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| rowspan=2|29(1) s |
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| α (50%) |
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| <sup>243</sup>Cf |
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| rowspan=2|(7/2+) |
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|- |
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| β<sup>+</sup> (50%) |
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| <sup>247</sup>Es |
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|- |
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| rowspan=3|<sup>248</sup>Fm |
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| rowspan=3 style="text-align:right" | 100 |
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| rowspan=3 style="text-align:right" | 148 |
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| rowspan=3|248.077195(13) |
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| rowspan=3|36(2) s |
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| α (99%) |
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| <sup>244</sup>Cf |
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| rowspan=3|0+ |
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|- |
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| β<sup>+</sup> (1%) |
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| <sup>248</sup>Es |
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|- |
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| SF (.05%) |
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| (various) |
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|- |
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| rowspan=2|<sup>249</sup>Fm |
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| rowspan=2 style="text-align:right" | 100 |
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| rowspan=2 style="text-align:right" | 149 |
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| rowspan=2|249.07903(11)# |
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| rowspan=2|2.6(7) min |
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| β<sup>+</sup> (85%) |
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| <sup>249</sup>Es |
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| rowspan=2|(7/2+)# |
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|- |
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| α (15%) |
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| <sup>245</sup>Cf |
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|- |
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| rowspan=3|<sup>250</sup>Fm |
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| rowspan=3 style="text-align:right" | 100 |
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| rowspan=3 style="text-align:right" | 150 |
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| rowspan=3|250.079521(13) |
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| rowspan=3|30(3) min |
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| α (90%) |
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| <sup>246</sup>Cf |
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| rowspan=3|0+ |
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|- |
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| [[Electron capture|EC]] (10%) |
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| <sup>250</sup>Es |
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|- |
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| SF (6E-4%) |
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| (various) |
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|- |
|- |
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| style="text-indent:1em" | <sup>250m</sup>Fm |
| style="text-indent:1em" | <sup>250m</sup>Fm |
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| colspan="3" style="text-indent:2em" | 1500(300)# keV |
| colspan="3" style="text-indent:2em" | 1500(300)# keV |
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| 1.8(1) s |
| 1.8(1) s |
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| [[Isomeric transition|IT]] |
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| <sup>250</sup>Fm |
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| 7,8# |
| 7,8# |
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|- |
|- |
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| <sup>251</sup>Fm |
| rowspan=2|<sup>251</sup>Fm |
||
| style="text-align:right" | 100 |
| rowspan=2 style="text-align:right" | 100 |
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| style="text-align:right" | 151 |
| rowspan=2 style="text-align:right" | 151 |
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| 251.081575(9) |
| rowspan=2|251.081575(9) |
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| 5.30(8) h |
| rowspan=2|5.30(8) h |
||
| |
| β<sup>+</sup> (98.2%) |
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| <sup>251</sup>Es |
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| rowspan=2|(9/2-) |
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|- |
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| α (1.8%) |
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| <sup>247</sup>Cf |
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|- |
|- |
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| style="text-indent:1em" | <sup>251m</sup>Fm |
| style="text-indent:1em" | <sup>251m</sup>Fm |
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| colspan="3" style="text-indent:2em" | 191(2) keV |
| colspan="3" style="text-indent:2em" | 191(2) keV |
||
| 15.2(23) µs |
| 15.2(23) µs |
||
| |
|||
| |
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| (5/2+) |
| (5/2+) |
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|- |
|- |
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| <sup>252</sup>Fm |
| rowspan=3|<sup>252</sup>Fm |
||
| style="text-align:right" | 100 |
| rowspan=3 style="text-align:right" | 100 |
||
| style="text-align:right" | 152 |
| rowspan=3 style="text-align:right" | 152 |
||
| 252.082467(6) |
| rowspan=3|252.082467(6) |
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| 25.39(4) h |
| rowspan=3|25.39(4) h |
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| α (99.99%) |
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| 0+ |
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| <sup>248</sup>Cf |
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| rowspan=3|0+ |
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|- |
|- |
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| SF (.0023%) |
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| <sup>253</sup>Fm |
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| (various) |
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| style="text-align:right" | 100 |
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| style="text-align:right" | 153 |
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| 253.085185(4) |
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| 3.00(12) d |
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| (1/2)+ |
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|- |
|- |
||
| <sup> |
| β<sup>+</sup>β<sup>+</sup> (rare) |
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| <sup>252</sup>Cf |
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| style="text-align:right" | 100 |
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| style="text-align:right" | 154 |
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| 254.0868542(30) |
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| 3.240(2) h |
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| 0+ |
|||
|- |
|- |
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| rowspan=2|<sup>253</sup>Fm |
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| <sup>255</sup>Fm<ref group="n">First isotope discovered (in fallout)</ref> |
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| style="text-align:right" | 100 |
| rowspan=2 style="text-align:right" | 100 |
||
| style="text-align:right" | |
| rowspan=2 style="text-align:right" | 153 |
||
| rowspan=2|253.085185(4) |
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| 255.089962(5) |
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| |
| rowspan=2|3.00(12) d |
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| EC (88%) |
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| 7/2+ |
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| <sup>253</sup>Es |
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| rowspan=2|(1/2)+ |
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|- |
|- |
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| α (12%) |
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| <sup>256</sup>Fm |
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| <sup>249</sup>Cf |
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| style="text-align:right" | 100 |
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|- |
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| style="text-align:right" | 156 |
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| rowspan=2|<sup>254</sup>Fm |
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| 256.091773(8) |
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| rowspan=2 style="text-align:right" | 100 |
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| 157.6(13) min |
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| rowspan=2 style="text-align:right" | 154 |
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| 0+ |
|||
| rowspan=2|254.0868542(30) |
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| rowspan=2|3.240(2) h |
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| α (99.94%) |
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| <sup>250</sup>Cf |
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| rowspan=2|0+ |
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|- |
|- |
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| SF (.06%) |
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| <sup>257</sup>Fm<ref group="n">Heaviest nuclide produced via [[neutron capture]]</ref> |
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| (various) |
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| style="text-align:right" | 100 |
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|- |
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| style="text-align:right" | 157 |
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| rowspan=2|<sup>255</sup>Fm<ref group="n">First isotope discovered (in fallout)</ref> |
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| 257.095105(7) |
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| rowspan=2 style="text-align:right" | 100 |
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| 100.5(2) d |
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| rowspan=2 style="text-align:right" | 155 |
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| (9/2+) |
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| rowspan=2|255.089962(5) |
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| rowspan=2|20.07(7) h |
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| α |
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| <sup>251</sup>Cf |
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| rowspan=2|7/2+ |
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|- |
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| SF (2E-5%) |
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| (various) |
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|- |
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| rowspan=2|<sup>256</sup>Fm |
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| rowspan=2 style="text-align:right" | 100 |
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| rowspan=2 style="text-align:right" | 156 |
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| rowspan=2|256.091773(8) |
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| rowspan=2|157.6(13) min |
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| SF (91.9%) |
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| (various) |
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| rowspan=2|0+ |
|||
|- |
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| α (8.1%) |
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| <sup>252</sup>Cf |
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|- |
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| rowspan=2|<sup>257</sup>Fm<ref group="n">Heaviest nuclide produced via [[neutron capture]]</ref> |
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| rowspan=2 style="text-align:right" | 100 |
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| rowspan=2 style="text-align:right" | 157 |
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| rowspan=2|257.095105(7) |
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| rowspan=2|100.5(2) d |
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| α (99.79%) |
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| <sup>253</sup>Cf |
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| rowspan=2|(9/2+) |
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|- |
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| SF (.21%) |
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| (various) |
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|- |
|- |
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| <sup>258</sup>Fm |
| <sup>258</sup>Fm |
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Line 141: | Line 248: | ||
| 258.09708(22)# |
| 258.09708(22)# |
||
| 370(14) µs |
| 370(14) µs |
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| SF |
|||
| (various) |
|||
| 0+ |
| 0+ |
||
|- |
|- |
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Line 148: | Line 257: | ||
| 259.1006(3)# |
| 259.1006(3)# |
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| 1.5(3) s |
| 1.5(3) s |
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| SF |
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| (various) |
|||
| 3/2+# |
| 3/2+# |
||
|- |
|- |
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Line 155: | Line 266: | ||
| 260.10268(54)# |
| 260.10268(54)# |
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| 1# min |
| 1# min |
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| |
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| |
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| 0+ |
| 0+ |
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|} |
|} |
Revision as of 13:55, 22 May 2011
Fermium (Fm) has no stable isotopes. There are 19 known radioisotopes ranging in atomic mass from 242Fm to 260Fm, and 2 nuclear isomers, 250mFm and 251mFm. The isotope with the longest half-life is 257Fm with a half-life of 100.5 days, and the longest-lived isomer is 250mFm with a half-life of 1.8 seconds. A standard atomic mass cannot be given due to fermium being an artificial element.
255Fm was the first isotope discovered (in fall out). Shortly after that discovery, but prior to its publication, 250Fm was synthesized in a lab.
Table
nuclide symbol |
Z(p) | N(n) | isotopic mass (u) |
half-life | decay mode(s)[1][n 1] |
daughter isotope(s) |
nuclear spin |
---|---|---|---|---|---|---|---|
excitation energy | |||||||
242Fm | 100 | 142 | 242.07343(43)# | 0.8(2) ms | SF | (various) | 0+ |
α (rare) | 238Cf | ||||||
243Fm | 100 | 143 | 243.07435(23)# | 210(60) ms [0.18(+8-4) s] |
α (60%) | 239Cf | 7/2-# |
β+ (40%) | 239Es | ||||||
SF (.57%) | (various) | ||||||
244Fm | 100 | 144 | 244.07408(30)# | 3.3(5) ms | SF (99%) | (various) | 0+ |
α (1%) | 240Cf | ||||||
245Fm | 100 | 145 | 245.07539(30)# | 4.2(13) s | α (95.7%) | 241Cf | 1/2+# |
β+ (4.2%) | 241Es | ||||||
SF (.13%) | (various) | ||||||
246Fm | 100 | 146 | 246.07530(4) | 1.1(2) s | α (85%) | 242Cf | 0+ |
β+ (10%) | 246Es | ||||||
β+, SF (10%) | (various) | ||||||
SF (4.5%) | (various) | ||||||
247Fm | 100 | 147 | 247.07685(15)# | 29(1) s | α (50%) | 243Cf | (7/2+) |
β+ (50%) | 247Es | ||||||
248Fm | 100 | 148 | 248.077195(13) | 36(2) s | α (99%) | 244Cf | 0+ |
β+ (1%) | 248Es | ||||||
SF (.05%) | (various) | ||||||
249Fm | 100 | 149 | 249.07903(11)# | 2.6(7) min | β+ (85%) | 249Es | (7/2+)# |
α (15%) | 245Cf | ||||||
250Fm | 100 | 150 | 250.079521(13) | 30(3) min | α (90%) | 246Cf | 0+ |
EC (10%) | 250Es | ||||||
SF (6E-4%) | (various) | ||||||
250mFm | 1500(300)# keV | 1.8(1) s | IT | 250Fm | 7,8# | ||
251Fm | 100 | 151 | 251.081575(9) | 5.30(8) h | β+ (98.2%) | 251Es | (9/2-) |
α (1.8%) | 247Cf | ||||||
251mFm | 191(2) keV | 15.2(23) µs | (5/2+) | ||||
252Fm | 100 | 152 | 252.082467(6) | 25.39(4) h | α (99.99%) | 248Cf | 0+ |
SF (.0023%) | (various) | ||||||
β+β+ (rare) | 252Cf | ||||||
253Fm | 100 | 153 | 253.085185(4) | 3.00(12) d | EC (88%) | 253Es | (1/2)+ |
α (12%) | 249Cf | ||||||
254Fm | 100 | 154 | 254.0868542(30) | 3.240(2) h | α (99.94%) | 250Cf | 0+ |
SF (.06%) | (various) | ||||||
255Fm[n 2] | 100 | 155 | 255.089962(5) | 20.07(7) h | α | 251Cf | 7/2+ |
SF (2E-5%) | (various) | ||||||
256Fm | 100 | 156 | 256.091773(8) | 157.6(13) min | SF (91.9%) | (various) | 0+ |
α (8.1%) | 252Cf | ||||||
257Fm[n 3] | 100 | 157 | 257.095105(7) | 100.5(2) d | α (99.79%) | 253Cf | (9/2+) |
SF (.21%) | (various) | ||||||
258Fm | 100 | 158 | 258.09708(22)# | 370(14) µs | SF | (various) | 0+ |
259Fm | 100 | 159 | 259.1006(3)# | 1.5(3) s | SF | (various) | 3/2+# |
260Fm | 100 | 160 | 260.10268(54)# | 1# min | 0+ |
- ^ Abbreviations:
EC: Electron capture
IT: Isomeric transition
SF: Spontaneous fission - ^ First isotope discovered (in fallout)
- ^ Heaviest nuclide produced via neutron capture
Notes
- Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
- Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.
- The isotopes denoted by an isotope number with an "m" are metastable isomers.
References
- Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. doi:10.1016/j.nuclphysa.2003.11.001.
{{cite journal}}
: CS1 maint: multiple names: authors list (link)
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. doi:10.1016/j.nuclphysa.2003.11.001.
- Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
{{cite journal}}
: Unknown parameter|laysummary=
ignored (help)
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. doi:10.1016/j.nuclphysa.2003.11.001.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
{{cite web}}
: Check date values in:|accessdate=
(help) - N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide (ed.). CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0849304859.
{{cite book}}
: Unknown parameter|nopp=
ignored (|no-pp=
suggested) (help)
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. doi:10.1016/j.nuclphysa.2003.11.001.