Isotopes of actinium explained

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.[1]

List of isotopes

|-| 203Ac[2] || style="text-align:right" | 89| style="text-align:right" | 114| | | α| 199Fr| (1/2+)||-|204Ac[3] || style="text-align:right" | 89| style="text-align:right" | 115|| | α| 200Fr|||-|205Ac[4] || style="text-align:right" | 89| style="text-align:right" | 116|| [3] | α| 201Fr| 9/2−?||-| 206Ac|| style="text-align:right" | 89| style="text-align:right" | 117| 206.01450(8)| 25(7) ms| α| 202Fr| (3+)||-| style="text-indent:1em" | 206m1Ac|| colspan="3" style="text-indent:2em" | 80(50) keV| 15(6) ms| α| 202Fr|||-| style="text-indent:1em" | 206m2Ac|| colspan="3" style="text-indent:2em" | 290(110)# keV| 41(16) ms| α| 202mFr| (10−)||-| 207Ac|| style="text-align:right" | 89| style="text-align:right" | 118| 207.01195(6)| 31(8) ms
[27(+11−6) ms]| α| 203Fr| 9/2−#||-| rowspan=2|208Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 119| rowspan=2|208.01155(6)| rowspan=2|97(16) ms
[95(+24−16) ms]| α (99%)| 204Fr| rowspan=2|(3+)| rowspan=2||-| β+ (1%)| 208Ra|-| rowspan=3 style="text-indent:1em" | 208mAc| rowspan=3|| rowspan=3 colspan="3" style="text-indent:2em" | 506(26) keV| rowspan=3|28(7) ms
[25(+9−5) ms]| α (89%)| 204Fr| rowspan=3|(10−)| rowspan=3||-| IT (10%)| 208Ac|-| β+ (1%)| 208Ra|-| rowspan=2|209Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 120| rowspan=2|209.00949(5)| rowspan=2|92(11) ms| α (99%)| 205Fr| rowspan=2|(9/2−)| rowspan=2||-| β+ (1%)| 209Ra|-| rowspan=2|210Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 121| rowspan=2|210.00944(6)| rowspan=2|350(40) ms| α (96%)| 206Fr| rowspan=2|7+#| rowspan=2||-| β+ (4%)| 210Ra|-| rowspan=2|211Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 122| rowspan=2|211.00773(8)| rowspan=2|213(25) ms| α (99.8%)| 207Fr| rowspan=2|9/2−#| rowspan=2| |-| β+ (.2%)| 211Ra|-| rowspan=2|212Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 123| rowspan=2|212.00781(7)| rowspan=2|920(50) ms| α (97%)| 208Fr| rowspan=2|6+#| rowspan=2||-| β+ (3%)| 212Ra|-| rowspan=2|213Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 124| rowspan=2|213.00661(6)| rowspan=2|731(17) ms| α| 209Fr| rowspan=2|(9/2−)#| rowspan=2||-| β+ (rare)| 213Ra|-| rowspan=2|214Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 125| rowspan=2|214.006902(24)| rowspan=2|8.2(2) s| α (89%)| 210Fr| rowspan=2|(5+)#| rowspan=2||-| β+ (11%)| 214Ra|-| rowspan=2|215Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 126| rowspan=2|215.006454(23)| rowspan=2|0.17(1) s| α (99.91%)| 211Fr| rowspan=2|9/2−| rowspan=2||-| β+ (.09%)| 215Ra|-| rowspan=2|216Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 127| rowspan=2|216.008720(29)| rowspan=2|0.440(16) ms| α| 212Fr| rowspan=2|(1−)| rowspan=2||-| β+ (7×10−5%)| 216Ra|-| style="text-indent:1em" | 216mAc|| colspan="3" style="text-indent:2em" | 44(7) keV| 443(7) μs| α| 212Fr| (9−)||-| rowspan=2|217Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 128| rowspan=2|217.009347(14)| rowspan=2|69(4) ns| α| 213Fr| rowspan=2|9/2−| rowspan=2||-| β+ (6.9×10−9%)| 217Ra|-| style="text-indent:1em" | 217mAc|| colspan="3" style="text-indent:2em" | 2012(20) keV| 740(40) ns||| (29/2)+||-| 218Ac|| style="text-align:right" | 89| style="text-align:right" | 129| 218.01164(5)| 1.08(9) μs| α| 214Fr| (1−)#||-| style="text-indent:1em" | 218mAc|| colspan="3" style="text-indent:2em" | 584(50)# keV| 103(11) ns||| (11+)||-| rowspan=2|219Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 130| rowspan=2|219.01242(5)| rowspan=2|11.8(15) μs| α| 215Fr| rowspan=2|9/2−| rowspan=2||-| β+ (10−6%)| 219Ra|-| rowspan=2|220Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 131| rowspan=2|220.014763(16)| rowspan=2|26.36(19) ms| α| 216Fr| rowspan=2|(3−)| rowspan=2||-| β+ (5×10−4%)| 220Ra|-| 221Ac|| style="text-align:right" | 89| style="text-align:right" | 132| 221.01559(5)| 52(2) ms| α| 217Fr| 9/2−#||-| rowspan=2|222Ac| rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 133| rowspan=2|222.017844(6)| rowspan=2|5.0(5) s| α (99%)| 218Fr| rowspan=2|1−| rowspan=2||-| β+ (1%)| 222Ra|-| rowspan=3 style="text-indent:1em" | 222mAc| rowspan=3|| rowspan=3 colspan="3" style="text-indent:2em" | 200(150)# keV| rowspan=3|1.05(7) min| α (88.6%)| 218Fr| rowspan=3|high| rowspan=3||-| IT (10%)| 222Ac|-| β+ (1.4%)| 222Ra|-| rowspan=3|223Ac| rowspan=3|| rowspan=3 style="text-align:right" | 89| rowspan=3 style="text-align:right" | 134| rowspan=3|223.019137(8)| rowspan=3|2.10(5) min| α (99%)| 219Fr| rowspan=3|(5/2−)| rowspan=3||-| EC (1%)| 223Ra|-| CD (3.2×10−9%)| 209Bi
14C|-| rowspan=3|224Ac| rowspan=3|| rowspan=3 style="text-align:right" | 89| rowspan=3 style="text-align:right" | 135| rowspan=3|224.021723(4)| rowspan=3|2.78(17) h| β+ (90.9%)| 224Ra| rowspan=3|0−| rowspan=3||-| α (9.1%)| 220Fr|-| β− (1.6%)| 224Th|-| rowspan=2|225Ac[5] | rowspan=2|| rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 136| rowspan=2|225.023230(5)| rowspan=2|10.0(1) d| α| 221Fr| rowspan=2|(3/2−)| rowspan=2|Trace[6] |-| CD (6×10−10%)| 211Bi
14C|-| rowspan=3|226Ac| rowspan=3|| rowspan=3 style="text-align:right" | 89| rowspan=3 style="text-align:right" | 137| rowspan=3|226.026098(4)| rowspan=3|29.37(12) h| β− (83%)| 226Th| rowspan=3|(1)(−#)| rowspan=3||-| EC (17%)| 226Ra|-| α (.006%)| 222Fr|-| rowspan=2|227Ac| rowspan=2|Actinium[7] | rowspan=2 style="text-align:right" | 89| rowspan=2 style="text-align:right" | 138| rowspan=2|227.0277521(26)| rowspan=2|21.772(3) y| β− (98.62%)| 227Th| rowspan=2|3/2−| rowspan=2|Trace[8] |-| α (1.38%)| 223Fr|-| 228Ac| Mesothorium 2| style="text-align:right" | 89| style="text-align:right" | 139| 228.0310211(27)| 6.13(2) h| β−| 228Th| 3+| Trace[9] |-| 229Ac|| style="text-align:right" | 89| style="text-align:right" | 140| 229.03302(4)| 62.7(5) min| β−| 229Th| (3/2+)||-| 230Ac|| style="text-align:right" | 89| style="text-align:right" | 141| 230.03629(32)| 122(3) s| β−| 230Th| (1+)||-| 231Ac|| style="text-align:right" | 89| style="text-align:right" | 142| 231.03856(11)| 7.5(1) min| β−| 231Th| (1/2+)||-| 232Ac|| style="text-align:right" | 89| style="text-align:right" | 143| 232.04203(11)| 119(5) s| β−| 232Th| (1+)||-| 233Ac|| style="text-align:right" | 89| style="text-align:right" | 144| 233.04455(32)#| 145(10) s| β−| 233Th| (1/2+)||-| 234Ac|| style="text-align:right" | 89| style="text-align:right" | 145| 234.04842(43)#| 44(7) s| β−| 234Th|||-| 235Ac|| style="text-align:right" | 89| style="text-align:right" | 146| 235.05123(38)#| 60(4) s| β−| 235Th| 1/2+#||-| 236Ac[10] || style="text-align:right" | 89| style="text-align:right" | 147| 236.05530(54)#| | β−| 236Th||

Actinides vs fission products

See also

References

Notes and References

  1. Book: 2005 . Chemical Elements . Van Nostrand's Encyclopedia of Chemistry . G. D. Considine . 332 . . 978-0-471-61525-5.
  2. Wang . J. G. . Gan . Z. G. . Zhang . Z. Y. . Huang . M. H. . Ma . L. . Zhang . M. M. . Yang . H. B. . Yang . C. L. . Qiang . Y. H. . Huang . X. Y. . Zhao . Z. . Xu . S. Y. . Li . Z. C. . Chen . L. X. . Sun . L. C. . Zhou . H. . Zhang . X. . Wu . X. L. . Tian . Y. L. . Wang . Y. S. . Wang . J. Y. . Huang . W. X. . Liu . M. L. . Lu . Z. W. . He . Y. . Ren . Z. Z. . Zhou . S. G. . Zhou . X. H. . Xu . H. S. . Utyonkov . V. K. . Voinov . A. A. . Tsyganov . Yu. S. . Polyakov . A. N. . 3 . α-decay properties of new neutron-deficient isotope 203Ac . Physics Letters B . 1 March 2024 . 850 . 138503 . 10.1016/j.physletb.2024.138503 . 0370-2693. free .
  3. Huang . M. H. . Gan . Z. G. . Zhang . Z. Y. . Ma . L. . Wang . J. G. . Zhang . M. M. . Yang . H. B. . Yang . C. L. . Huang . X. Y. . Zhao . Z. . Xu . S. Y. . Chen . L. X. . Wen . X. J. . Niu . Y. F. . Yuan . C. X. . Tian . Y. L. . Wang . Y. S. . Wang . J. Y. . Liu . M. L. . Qiang . Y. H. . Yang . W. Q. . Zhang . H. B. . Lu . Z. W. . Guo . S. . Huang . W. X. . He . Y. . Ren . Z. Z. . Zhou . S. G. . Zhou . X. H. . Xu . H. S. . Utyonkov . V. K. . Voinov . A. A. . Tsyganov . Yu. S. . Polyakov . A. N. . 3 . α decay of the new isotope 204Ac . Physics Letters B . 10 November 2022 . 834 . 137484 . 10.1016/j.physletb.2022.137484 . 2022PhLB..83437484H . 252730841 . en . 0370-2693. free .
  4. Zhang . Z. Y. . Gan . Z. G. . Ma . L. . Yu . L. . Yang . H. B. . Huang . T. H. . Li . G. S. . Tian . Y. L. . Wang . Y. S. . Xu . X. X. . Huang . M. H. . Luo . C. . Ren . Z. Z. . Zhou . S.G. . Zhou . X. H. . Xu . H. S. . Xiao . G. Q. . 3 . α decay of the new neutron-deficient isotope 205Ac. Physical Review C . 89 . 1 . 014308 . January 2014 . 10.1103/PhysRevC.89.014308. 2014PhRvC..89a4308Z .
  5. Has medical uses
  6. Intermediate decay product of 237Np
  7. Source of element's name
  8. Intermediate decay product of 235U
  9. Intermediate decay product of 232Th
  10. Chen. L.. etal. 2010. Discovery and investigation of heavy neutron-rich isotopes with time-resolved Schottky spectrometry in the element range from thallium to actinium . Physics Letters B. 691. 5. 234–237. 10.1016/j.physletb.2010.05.078. 2010PhLB..691..234C .

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