Einsteinium (99Es) is asynthetic element, and thus astandard atomic weight cannot be given. Like all synthetic elements, it has nostable isotopes. The firstisotope to be discovered (innuclear fallout from theIvy MikeH-bombtest) was253Es in 1952. There are 18 knownradioisotopes from240Es to257Es, and 4nuclear isomers. The longest-lived isotope is252Es with ahalf-life of 471.7 days, or around 1.293 years.
| |||||||||||||||||||||||||||||||||||||||||||||
List of isotopes
edit| Nuclide [n 1] | Z | N | Isotopic mass(Da)[2] [n 2][n 3] | Half-life[1] | Decay mode[1] [n 4] | Daughter isotope | Spin and parity[1] [n 5][n 6] | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Excitation energy[n 6] | |||||||||||||||||||
| 240Es | 99 | 141 | 240.06895(39)# | 6.0(17) s | α (70%) | 236Bk | 4−# | ||||||||||||
| β+ (30%) | 240Cf | ||||||||||||||||||
| β+,SF (0.16%) | (various) | ||||||||||||||||||
| 241Es[3] | 99 | 142 | 241.06859(25)# | 4.3+2.4 −1.2 s | α | 237Bk | 3/2−# | ||||||||||||
| β+? | 241Cf | ||||||||||||||||||
| 242Es[4] | 99 | 143 | 242.06957(28)# | 16.9(8) s | β+ | 242Cf | 2+# | ||||||||||||
| α (41%) | 238Bk | ||||||||||||||||||
| β+, SF (1.5%) | (various) | ||||||||||||||||||
| 243Es | 99 | 144 | 243.06951(22)# | 22.1(14) s | α (61%) | 239Bk | (7/2+) | ||||||||||||
| β+ (39%) | 243Cf | ||||||||||||||||||
| 244Es | 99 | 145 | 244.07088(20)# | 37(4) s | β+ (95%) | 244Cf | 6+# | ||||||||||||
| α (5%) | 240Bk | ||||||||||||||||||
| β+, SF (0.011%) | (various) | ||||||||||||||||||
| 245Es | 99 | 146 | 245.07119(18)# | 1.11(6) min | β+ (51%) | 245Cf | (3/2−) | ||||||||||||
| α (49%) | 241Bk | ||||||||||||||||||
| 245mEs[n 7] | 30(15)# keV | >50# μs | IT? | 245Es | 7/2+# | ||||||||||||||
| α? | 241Bk | ||||||||||||||||||
| β+? | 245Cf | ||||||||||||||||||
| 246Es | 99 | 147 | 246.072806(97) | 7.5(5) min | β+ (90.1%) | 246Cf | 4−# | ||||||||||||
| α (9.9%) | 242Bk | ||||||||||||||||||
| β+, SF (.003%) | (various) | ||||||||||||||||||
| 247Es | 99 | 148 | 247.073622(21) | 4.55(26) min | β+ (93%) | 247Cf | (7/2+) | ||||||||||||
| α (7%) | 243Bk | ||||||||||||||||||
| SF? | (various) | ||||||||||||||||||
| 248Es | 99 | 149 | 248.075469(56)# | 24(3) min | β+ (99.75%) | 248Cf | 2−# | ||||||||||||
| α (.25%) | 244Bk | ||||||||||||||||||
| β+, SF (3.5×10−4%) | (various) | ||||||||||||||||||
| 249Es | 99 | 150 | 249.076409(32)# | 102.2(6) min | β+ (99.43%) | 249Cf | 7/2+ | ||||||||||||
| α (.57%) | 245Bk | ||||||||||||||||||
| 250Es | 99 | 151 | 250.07861(11)# | 8.6(1) h | β+ | 250Cf | 6(+) | ||||||||||||
| α? | 246Bk | ||||||||||||||||||
| 250mEs[n 7] | 200(150)# keV | 2.22(5) h | β+ | 250Cf | 1(−) | ||||||||||||||
| α? | 246Bk | ||||||||||||||||||
| 251Es | 99 | 152 | 251.0799914(57) | 33(1) h | EC (99.5%) | 251Cf | 3/2− | ||||||||||||
| α (.5%) | 247Bk | ||||||||||||||||||
| 252Es | 99 | 153 | 252.082979(54) | 471.7(19) d | α (78(2)%) | 248Bk | (4+) | ||||||||||||
| EC (22(2)%) | 252Cf | ||||||||||||||||||
| 253Es[n 8] | 99 | 154 | 253.0848212(13) | 20.47(3) d | α | 249Bk | 7/2+ | ||||||||||||
| SF (8.7×10−6%) | (various) | ||||||||||||||||||
| 254Es | 99 | 155 | 254.0880243(32) | 275.7(5) d | α[n 9] | 250Bk | 7+ | ||||||||||||
| β− (1.74×10−4%) | 254Fm | ||||||||||||||||||
| SF (<3×10−6%) | (various) | ||||||||||||||||||
| 254mEs | 80.4(11) keV | 39.3(2) h | β− (98(2)%) | 254Fm | 2+ | ||||||||||||||
| IT (<3%) | 254Es | ||||||||||||||||||
| α (0.32(1)%) | 250Bk | ||||||||||||||||||
| EC (0.076(7)%) | 254Cf | ||||||||||||||||||
| SF (<0.045%) | (various) | ||||||||||||||||||
| 255Es | 99 | 156 | 255.090274(12) | 39.8(12) d | β− (92.0%) | 255Fm | (7/2+) | ||||||||||||
| α (8.0%) | 251Bk | ||||||||||||||||||
| SF (.0041%) | (various) | ||||||||||||||||||
| 256Es | 99 | 157 | 256.09360(11)# | 7.6 h | β− | 256Fm | 7+# | ||||||||||||
| β−, SF (.002%) | (various) | ||||||||||||||||||
| 256mEs[n 7] | 0(100)# keV | 25.4(12) min | β− | 256Fm | 0+# | ||||||||||||||
| 257Es | 99 | 158 | 257.09598(44)# | 7.7(2) d | β− | 257Fm | 7/2+# | ||||||||||||
| α? | 253Bk | ||||||||||||||||||
| This table header & footer: | |||||||||||||||||||
- ^mEs – Excitednuclear isomer.
- ^( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
- ^# – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
- ^Modes of decay:
EC: Electron capture IT: Isomeric transition SF: Spontaneous fission - ^( ) spin value – Indicates spin with weak assignment arguments.
- ^ab# – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
- ^abcOrder of ground state and isomer is uncertain.
- ^Most common isotope
- ^Theoretically capable of electron capture to254Cf[1]
References
edit- ^abcdeKondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021)."The NUBASE2020 evaluation of nuclear properties"(PDF).Chinese Physics C.45 (3): 030001.doi:10.1088/1674-1137/abddae.
- ^Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*".Chinese Physics C.45 (3): 030003.doi:10.1088/1674-1137/abddaf.
- ^Khuyagbaatar, J.; Albers, H. M.; Block, M.; Brand, H.; Cantemir, R. A.; Di Nitto, A.; Düllmann, Ch. E.; Götz, M.; Götz, S.; Heßberger, F. P.; Jäger, E.; Kindler, B.; Kratz, J. V.; Krier, J.; Kurz, N.; Lommel, B.; Lens, L.; Mistry, A.; Schausten, B.; Uusitalo, J.; Yakushev, A. (1 October 2020)."Search for Electron-Capture Delayed Fission in the New Isotope244Md".Physical Review Letters.125 (14): 142504.Bibcode:2020PhRvL.125n2504K.doi:10.1103/PhysRevLett.125.142504.PMID 33064498.S2CID 223546973.
- ^Khuyagbaatar, J.; Cantemir, R. A.; Düllmann, Ch. E.; Jäger, E.; Kindler, B.; Krier, J.; Kurz, N.; Lommel, B.; Schausten, B.; Yakushev, A. (2024-03-18). "Decay properties of the neutron-deficient isotope Es 242".Physical Review C.109 (3).arXiv:2408.01714.doi:10.1103/PhysRevC.109.034311.ISSN 2469-9985.
- Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean;Wapstra, Aaldert Hendrik (2003),"The NUBASE evaluation of nuclear and decay properties",Nuclear Physics A,729:3–128,Bibcode:2003NuPhA.729....3A,doi:10.1016/j.nuclphysa.2003.11.001
- Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean;Wapstra, Aaldert Hendrik (2003),"The NUBASE evaluation of nuclear and decay properties",Nuclear Physics A,729:3–128,Bibcode:2003NuPhA.729....3A,doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center."NuDat 2.x database".Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.).CRC Handbook of Chemistry and Physics (85th ed.).Boca Raton, Florida:CRC Press.ISBN 978-0-8493-0485-9.