## More Chemistry

All of the atomic nuclei of the chemical element seaborgium are summarized under seaborgium isotopes; these consist of an atomic nucleus with 106 protons and in the uncharged state of 106 electrons. The difference between the individual seaborgium isotopes lies in the number of neutrons in the nucleus - and thus in the mass number.

As in the other synthetic elements, there are no stable isotopes of seaborgium either, i. H. the nuclides decay quickly and are highly radioactive.

The undoubted first isotope of Sg produced was ^{263m}Sg in 1974.

There are now 12 radioisotopes in total between ^{258}Sg and ^{271}Sg as well as 2 core isomers (^{261m}Sg and ^{263m}Sg) are known. These were either generated by bombarding two lighter atomic nuclei or were temporarily observed as intermediate products during the decay of heavier atomic nuclei.

The longest-lived seaborgium isotope is ^{269}Sg with a half-life of 3.1 minutes; it occurs in the decay chain of one of the flerovium isotopes - ^{285}Fl.

Isotope Nuclide | E | N | Atomic Mass [Nuclear Mass] {Mass Excess} | Spin I(h/2π) | Parent |
---|---|---|---|---|---|

1 | 2 | 3 | 4 | 5 | 6 |

Seaborgium-258 | 258106Sg | 152 | 258.11298(44) u [258.0548398 u] {105.24019 MeV} | 0+ | |

Seaborgium-259 | 259106Sg | 153 | 259.11435(12) u [259.0562098 u] {106.51634 MeV} | 1/2+ | |

Seaborgium-260 | 260106Sg | 154 | 260.114384(22) u [260.0562438 u] {106.54801 MeV} | 0+ | |

Seaborgium-261 | 261106Sg | 155 | 261.115948(20) u [261.0578078 u] {108.00487 MeV} | 7/2+ | |

Seaborgium-261m | 261m106Sg | 155 | 261.115948(20) u [261.0578078 u] {108.00487 MeV} | ||

Seaborgium-262 | 262106Sg | 156 | 262.11634(4) u [262.0581998 u] {108.37001 MeV} | 0+ | |

Seaborgium-263 | 263106Sg | 157 | 263.11829(10) u [263.0601498 u] {110.18643 MeV} | 9/2+ | |

Seaborgium-263m | 263m106Sg | 157 | 263.11829(10) u [263.0601498 u] {110.18643 MeV} | 3/2+ | |

Seaborgium-264 | 264106Sg | 158 | 264.11893(30) u [264.0607898 u] {110.78258 MeV} | 0+ | |

Seaborgium-265 | 265106Sg | 159 | 265121090(15) u [265121089.94186 u] {246958457762.55 MeV} | ||

Seaborgium-265m | 265m106Sg | 159 | 265121090(15) u [265121089.94186 u] {246958457762.55 MeV} | ||

Seaborgium-266 | 266106Sg | 160 | 266.12197(26) u [266.0638298 u] {113.61432 MeV} | 0+ | |

Seaborgium-267 | 267106Sg | 161 | 267.124320(280) u [267.0661798 u] {115.80333 MeV} | ||

Seaborgium-268 | 268106Sg | 162 | |||

Seaborgium-269 | 269106Sg | 163 | 269.1285(4) u [269.0703598 u] {119.69698 MeV} | ||

Seaborgium-270 | 270106Sg | 164 | |||

Seaborgium-271 | 271106Sg | 165 | 271.133780(630) u [271.0756398 u] {124.61527 MeV} |

Isotope | Radioactive Decay | Extern | |||
---|---|---|---|---|---|

Half-life | Decay Mode | Probability | Energy | ||

7 | 8 | 9 | 10 | 11 | 12 |

Sg-258 | 2.5 (+9-7) ms | SF ^{}divα ^{254}Rf | 90 % ≤ 20 % | 9.62(30) MeV | AL |

Sg-259 | 0.29(5) s | α → ^{255}RfSF ^{}divEC → ^{259}Db | 90(10) % | 9.765(8) MeV 4.53(13) MeV | AL |

Sg-260 | 3.6(9) ms | α → ^{256}RfSF ^{}div | 50 % 50 % | 9.901(10) MeV | AL |

Sg-261 | 0.23(6) s | α → ^{257}RfSF ^{}div | 9.714(15)) MeV | AL | |

Sg-261m | 92 ms | AL | |||

Sg-262 | 6.9 ms | SF ^{}divα → ^{258}Rf | ≥ 78 % ≤ 12 % | 9.60(15) MeV | AL |

Sg-263 | 1.0(2) s | α → ^{259}RfSF ^{}div | > 70 % < 30 % | 9.40(6) MeV | AL |

Sg-263m | 0.12 s | α → ^{259}RfIso → ^{263}Sg | ? ? | AL | |

Sg-264 | 37(+27-11) ms | SF ^{}divα → ^{260}Rf | < 36 % | 9.21(20) MeV | AL |

Sg-265 | 14.4(+37-25) s | α ^{261}RfSF ^{}div | ≥ 50 % ≤ 50 % | 9.051(123) MeV | AL |

Sg-265m | 8.5 s | α → ^{261}RfSF ^{}div | |||

Sg-266 | 0.34 s | α ^{262}RfSF ^{}div | 18 % | 8.80(10) MeV | AL |

Sg-267 | 84 s | α → ^{263}RfSF ^{}div | 17 % 83 % | 8.625(212) MeV | AL |

Sg-268 | - unknown - | AL | |||

Sg-269 | 130(70) s | α → ^{265}RfSF ^{}div | ca. 100 % ? | 8.577(75) MeV | AL |

Sg-270 | - unknown - | AL | |||

Sg-271 | 96 s | α → ^{267}RfSF ^{}div | 50 % 50 % | 8.748(138) MeV | AL |

Notes (related to the columns):

1 - name of the nuclide, isotope.

2 - E: isotope symbol with mass number (superscript; number of nucleons) and atomic number (subscript; number of protons).

3 - *N*: number of neutrons.

4 - relative atomic mass of the Seaborgium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to ^{12}C = 12.00000 [2]. In addition, the mass excess is given in MeV.

5 - nuclear spin *I*, unit: h/2π.

6 - source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.

7 - isotope notation in short form.

8 - decay: half-live of the Seaborgium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).

9 - decay mode: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β^{-} = beta minus decay with electron emission; EC = electron capture; β^{+} = positron emission; ε = β^{+} and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.

10 - decay probability in percent (%).

11 - decay energy; Particle energy related to decay type.

12 - other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.

~ - Theoretical values or systematic trends.

- unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

**Properties of the Seaborgium nucleides**

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

**Seaborgium: NMR properties **

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

**More sources:**

[8] - **Isotopic abundances, atomic weights and isotopic masses:** see respective keyword.

**Last update: **2022-12-12

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