Isotopes of actinium
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Actinium (89Ac) has no stable isotopes and no characteristic terrestrial isotopic composition, thus a standard atomic weight cannot be given. There are 34 known isotopes, from 203Ac to 236Ac, and 7 isomers. Three isotopes are found in nature, 225Ac, 227Ac and 228Ac, as intermediate decay products of, respectively, 237Np, 235U, and 232Th. 228Ac and 225Ac are extremely rare, so almost all natural actinium is 227Ac.
The most stable isotopes are 227Ac with a half-life of 21.772 years, 225Ac with a half-life of 10.0 days, and 226Ac with a half-life of 29.37 hours. All other isotopes have half-lives under 10 hours, and most under a minute. The shortest-lived known isotope is 217Ac with a half-life of 69 ns.
Purified 227Ac comes into equilibrium with its decay products (227Th and 223Fr) after 185 days.[2]
List of isotopes
[edit]Nuclide [n 1] |
Historic name |
Z | N | Isotopic mass (Da) [n 2][n 3] |
Half-life |
Decay mode [n 4] |
Daughter isotope [n 5] |
Spin and parity [n 6][n 7] |
Isotopic abundance | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Excitation energy[n 7] | |||||||||||||||||||
203Ac[3] | 89 | 114 | 56+269 −26 μs |
α | 199Fr | (1/2+) | |||||||||||||
204Ac[4] | 89 | 115 | 7.4+2.2 −1.4 ms |
α | 200Fr | ||||||||||||||
205Ac[5] | 89 | 116 | 7.7+2.7 −1.6 ms[4] |
α | 201Fr | 9/2−? | |||||||||||||
206Ac | 89 | 117 | 206.01450(8) | 25(7) ms | α | 202Fr | (3+) | ||||||||||||
206m1Ac | 80(50) keV | 15(6) ms | α | 202Fr | |||||||||||||||
206m2Ac | 290(110)# keV | 41(16) ms | α | 202mFr | (10−) | ||||||||||||||
207Ac | 89 | 118 | 207.01195(6) | 31(8) ms [27(+11−6) ms] |
α | 203Fr | 9/2−# | ||||||||||||
208Ac | 89 | 119 | 208.01155(6) | 97(16) ms [95(+24−16) ms] |
α (99%) | 204Fr | (3+) | ||||||||||||
β+ (1%) | 208Ra | ||||||||||||||||||
208mAc | 506(26) keV | 28(7) ms [25(+9−5) ms] |
α (89%) | 204Fr | (10−) | ||||||||||||||
IT (10%) | 208Ac | ||||||||||||||||||
β+ (1%) | 208Ra | ||||||||||||||||||
209Ac | 89 | 120 | 209.00949(5) | 92(11) ms | α (99%) | 205Fr | (9/2−) | ||||||||||||
β+ (1%) | 209Ra | ||||||||||||||||||
210Ac | 89 | 121 | 210.00944(6) | 350(40) ms | α (96%) | 206Fr | 7+# | ||||||||||||
β+ (4%) | 210Ra | ||||||||||||||||||
211Ac | 89 | 122 | 211.00773(8) | 213(25) ms | α (99.8%) | 207Fr | 9/2−# | ||||||||||||
β+ (.2%) | 211Ra | ||||||||||||||||||
212Ac | 89 | 123 | 212.00781(7) | 920(50) ms | α (97%) | 208Fr | 6+# | ||||||||||||
β+ (3%) | 212Ra | ||||||||||||||||||
213Ac | 89 | 124 | 213.00661(6) | 731(17) ms | α | 209Fr | (9/2−)# | ||||||||||||
β+ (rare) | 213Ra | ||||||||||||||||||
214Ac | 89 | 125 | 214.006902(24) | 8.2(2) s | α (89%) | 210Fr | (5+)# | ||||||||||||
β+ (11%) | 214Ra | ||||||||||||||||||
215Ac | 89 | 126 | 215.006454(23) | 0.17(1) s | α (99.91%) | 211Fr | 9/2− | ||||||||||||
β+ (.09%) | 215Ra | ||||||||||||||||||
216Ac | 89 | 127 | 216.008720(29) | 0.440(16) ms | α | 212Fr | (1−) | ||||||||||||
β+ (7×10−5%) | 216Ra | ||||||||||||||||||
216mAc | 44(7) keV | 443(7) μs | α | 212Fr | (9−) | ||||||||||||||
217Ac | 89 | 128 | 217.009347(14) | 69(4) ns | α | 213Fr | 9/2− | ||||||||||||
β+ (6.9×10−9%) | 217Ra | ||||||||||||||||||
217mAc | 2012(20) keV | 740(40) ns | (29/2)+ | ||||||||||||||||
218Ac | 89 | 129 | 218.01164(5) | 1.08(9) μs | α | 214Fr | (1−)# | ||||||||||||
218mAc | 584(50)# keV | 103(11) ns | (11+) | ||||||||||||||||
219Ac | 89 | 130 | 219.01242(5) | 11.8(15) μs | α | 215Fr | 9/2− | ||||||||||||
β+ (10−6%) | 219Ra | ||||||||||||||||||
220Ac | 89 | 131 | 220.014763(16) | 26.36(19) ms | α | 216Fr | (3−) | ||||||||||||
β+ (5×10−4%) | 220Ra | ||||||||||||||||||
221Ac | 89 | 132 | 221.01559(5) | 52(2) ms | α | 217Fr | 9/2−# | ||||||||||||
222Ac | 89 | 133 | 222.017844(6) | 5.0(5) s | α (99%) | 218Fr | 1− | ||||||||||||
β+ (1%) | 222Ra | ||||||||||||||||||
222mAc | 200(150)# keV | 1.05(7) min | α (88.6%) | 218Fr | high | ||||||||||||||
IT (10%) | 222Ac | ||||||||||||||||||
β+ (1.4%) | 222Ra | ||||||||||||||||||
223Ac | 89 | 134 | 223.019137(8) | 2.10(5) min | α (99%) | 219Fr | (5/2−) | ||||||||||||
EC (1%) | 223Ra | ||||||||||||||||||
CD (3.2×10−9%) | 209Bi 14C | ||||||||||||||||||
224Ac | 89 | 135 | 224.021723(4) | 2.78(17) h | β+ (90.9%) | 224Ra | 0− | ||||||||||||
α (9.1%) | 220Fr | ||||||||||||||||||
β− (1.6%) | 224Th | ||||||||||||||||||
225Ac[n 8] | 89 | 136 | 225.023230(5) | 10.0(1) d | α | 221Fr | (3/2−) | Trace[n 9] | |||||||||||
CD (6×10−10%) | 211Bi 14C | ||||||||||||||||||
226Ac | 89 | 137 | 226.026098(4) | 29.37(12) h | β− (83%) | 226Th | (1)(−#) | ||||||||||||
EC (17%) | 226Ra | ||||||||||||||||||
α (.006%) | 222Fr | ||||||||||||||||||
227Ac | Actinium[n 10] | 89 | 138 | 227.0277521(26) | 21.772(3) y | β− (98.62%) | 227Th | 3/2− | Trace[n 11] | ||||||||||
α (1.38%) | 223Fr | ||||||||||||||||||
228Ac | Mesothorium 2 | 89 | 139 | 228.0310211(27) | 6.13(2) h | β− | 228Th | 3+ | Trace[n 12] | ||||||||||
229Ac | 89 | 140 | 229.03302(4) | 62.7(5) min | β− | 229Th | (3/2+) | ||||||||||||
230Ac | 89 | 141 | 230.03629(32) | 122(3) s | β− | 230Th | (1+) | ||||||||||||
231Ac | 89 | 142 | 231.03856(11) | 7.5(1) min | β− | 231Th | (1/2+) | ||||||||||||
232Ac | 89 | 143 | 232.04203(11) | 119(5) s | β− | 232Th | (1+) | ||||||||||||
233Ac | 89 | 144 | 233.04455(32)# | 145(10) s | β− | 233Th | (1/2+) | ||||||||||||
234Ac | 89 | 145 | 234.04842(43)# | 44(7) s | β− | 234Th | |||||||||||||
235Ac | 89 | 146 | 235.05123(38)# | 60(4) s | β− | 235Th | 1/2+# | ||||||||||||
236Ac[6] | 89 | 147 | 236.05530(54)# | 72+345 −33 s |
β− | 236Th | |||||||||||||
This table header & footer: |
- ^ mAc – Excited nuclear 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:
CD: Cluster decay EC: Electron capture IT: Isomeric transition - ^ Bold italics symbol as daughter – Daughter product is nearly stable.
- ^ ( ) spin value – Indicates spin with weak assignment arguments.
- ^ a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
- ^ Has medical uses
- ^ Intermediate decay product of 237Np
- ^ Source of element's name
- ^ Intermediate decay product of 235U
- ^ Intermediate decay product of 232Th
Actinides vs fission products
[edit]Actinides[7] by decay chain | Half-life range (a) |
Fission products of 235U by yield[8] | ||||||
---|---|---|---|---|---|---|---|---|
4n | 4n + 1 | 4n + 2 | 4n + 3 | 4.5–7% | 0.04–1.25% | <0.001% | ||
228Ra№ | 4–6 a | 155Euþ | ||||||
244Cmƒ | 241Puƒ | 250Cf | 227Ac№ | 10–29 a | 90Sr | 85Kr | 113mCdþ | |
232Uƒ | 238Puƒ | 243Cmƒ | 29–97 a | 137Cs | 151Smþ | 121mSn | ||
248Bk[9] | 249Cfƒ | 242mAmƒ | 141–351 a |
No fission products have a half-life | ||||
241Amƒ | 251Cfƒ[10] | 430–900 a | ||||||
226Ra№ | 247Bk | 1.3–1.6 ka | ||||||
240Pu | 229Th | 246Cmƒ | 243Amƒ | 4.7–7.4 ka | ||||
245Cmƒ | 250Cm | 8.3–8.5 ka | ||||||
239Puƒ | 24.1 ka | |||||||
230Th№ | 231Pa№ | 32–76 ka | ||||||
236Npƒ | 233Uƒ | 234U№ | 150–250 ka | 99Tc₡ | 126Sn | |||
248Cm | 242Pu | 327–375 ka | 79Se₡ | |||||
1.53 Ma | 93Zr | |||||||
237Npƒ | 2.1–6.5 Ma | 135Cs₡ | 107Pd | |||||
236U | 247Cmƒ | 15–24 Ma | 129I₡ | |||||
244Pu | 80 Ma |
... nor beyond 15.7 Ma[11] | ||||||
232Th№ | 238U№ | 235Uƒ№ | 0.7–14.1 Ga | |||||
|
Notable isotopes
[edit]Actinium-225
[edit]Actinium-225 is a highly radioactive isotope with 136 neutrons. It is an alpha emitter and has a half-life of 9.919 days. As of 2024, it is being researched as a possible alpha source in targeted alpha therapy.[12][13][14] Actinium-225 undergoes a series of three alpha decays – via the short-lived francium-221 and astatine-217 – to 213Bi, which itself is used as an alpha source.[15] Another benefit is that the decay chain of 225Ac ends in the nuclide 209Bi,[note 1] which has a considerably shorter biological half-life than lead.[16][17] However, a major factor limiting its usage is the difficulty in producing the short-lived isotope, as it is most commonly isolated from aging parent nuclides (such as 233U); it may also be produced in cyclotrons, linear accelerators, or fast breeder reactors.[18]
Notes
[edit]- ^ Bismuth-209 decays into thallium-205 with a half-life exceeding 1019 years, but this half-life is so long that for practical purposes bismuth-209 can be considered stable.
See also
[edit]References
[edit]- ^ Kondev, 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.
- ^ G. D. Considine, ed. (2005). "Chemical Elements". Van Nostrand's Encyclopedia of Chemistry. Wiley-Interscience. p. 332. ISBN 978-0-471-61525-5.
- ^ Wang, J. G.; Gan, Z. G.; Zhang, Z. Y.; et al. (1 March 2024). "α-decay properties of new neutron-deficient isotope 203Ac". Physics Letters B. 850: 138503. doi:10.1016/j.physletb.2024.138503. ISSN 0370-2693.
- ^ a b Huang, M. H.; Gan, Z. G.; Zhang, Z. Y.; et al. (10 November 2022). "α decay of the new isotope 204Ac". Physics Letters B. 834: 137484. Bibcode:2022PhLB..83437484H. doi:10.1016/j.physletb.2022.137484. ISSN 0370-2693. S2CID 252730841.
- ^ Zhang, Z. Y.; Gan, Z. G.; Ma, L.; et al. (January 2014). "α decay of the new neutron-deficient isotope 205Ac". Physical Review C. 89 (1): 014308. Bibcode:2014PhRvC..89a4308Z. doi:10.1103/PhysRevC.89.014308.
- ^ Chen, L.; et al. (2010). "Discovery and investigation of heavy neutron-rich isotopes with time-resolved Schottky spectrometry in the element range from thallium to actinium" (PDF). Physics Letters B. 691 (5): 234–237. Bibcode:2010PhLB..691..234C. doi:10.1016/j.physletb.2010.05.078.
- ^ Plus radium (element 88). While actually a sub-actinide, it immediately precedes actinium (89) and follows a three-element gap of instability after polonium (84) where no nuclides have half-lives of at least four years (the longest-lived nuclide in the gap is radon-222 with a half life of less than four days). Radium's longest lived isotope, at 1,600 years, thus merits the element's inclusion here.
- ^ Specifically from thermal neutron fission of uranium-235, e.g. in a typical nuclear reactor.
- ^ Milsted, J.; Friedman, A. M.; Stevens, C. M. (1965). "The alpha half-life of berkelium-247; a new long-lived isomer of berkelium-248". Nuclear Physics. 71 (2): 299. Bibcode:1965NucPh..71..299M. doi:10.1016/0029-5582(65)90719-4.
"The isotopic analyses disclosed a species of mass 248 in constant abundance in three samples analysed over a period of about 10 months. This was ascribed to an isomer of Bk248 with a half-life greater than 9 [years]. No growth of Cf248 was detected, and a lower limit for the β− half-life can be set at about 104 [years]. No alpha activity attributable to the new isomer has been detected; the alpha half-life is probably greater than 300 [years]." - ^ This is the heaviest nuclide with a half-life of at least four years before the "sea of instability".
- ^ Excluding those "classically stable" nuclides with half-lives significantly in excess of 232Th; e.g., while 113mCd has a half-life of only fourteen years, that of 113Cd is eight quadrillion years.
- ^ A. Scheinberg, David; R. McDevitt, Michael (1 October 2011). "Actinium-225 in Targeted Alpha-Particle Therapeutic Applications". Current Radiopharmaceuticalse. 4 (4): 306–320. doi:10.2174/1874471011104040306. PMC 5565267. PMID 22202153.
- ^ Reissig, Falco; Bauer, David; Zarschler, Kristof; Novy, Zbynek; Bendova, Katerina; Ludik, Marie-Charlotte; Kopka, Klaus; Pietzsch, Hans-Jürgen; Petrik, Milos; Mamat, Constantin (20 April 2021). "Towards Targeted Alpha Therapy with Actinium-225: Chelators for Mild Condition Radiolabeling and Targeting PSMA—A Proof of Concept Study". Cancers. 13 (8): 1974. doi:10.3390/cancers13081974. PMC 8073976. PMID 33923965.
- ^ Bidkar, Anil P.; Zerefa, Luann; Yadav, Surekha; VanBrocklin, Henry F.; Flavell, Robert R. (2024). "Actinium-225 targeted alpha particle therapy for prostate cancer". Theranostics. 14 (7): 2969–2992. doi:10.7150/thno.96403.
- ^ Ahenkorah, Stephen; Cassells, Irwin; Deroose, Christophe M.; Cardinaels, Thomas; Burgoyne, Andrew R.; Bormans, Guy; Ooms, Maarten; Cleeren, Frederik (21 April 2021). "Bismuth-213 for Targeted Radionuclide Therapy: From Atom to Bedside". Pharmaceutics. 13 (5): 599. doi:10.3390/pharmaceutics13050599. PMC 8143329.
- ^ Handbook on the toxicology of metals. Volume 2: Specific metals (Fourth ed.). Amsterdam Boston Heidelberg London: Elsevier, Aademic Press. 2015. p. 655. ISBN 978-0-12-398293-3.
- ^ Wani, Ab Latif; Ara, Anjum; Usmani, Jawed Ahmad (1 June 2015). "Lead toxicity: a review". Interdisciplinary Toxicology. 8 (2): 55–64. doi:10.1515/intox-2015-0009. PMC 4961898.
- ^ Dhiman, Deeksha; Vatsa, Rakhee; Sood, Ashwani (September 2022). "Challenges and opportunities in developing Actinium-225 radiopharmaceuticals". Nuclear Medicine Communications. 43 (9): 970–977. doi:10.1097/MNM.0000000000001594. PMID 35950353.
- 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.