Radium (88Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given. The longest lived, and most common, isotope of radium is 226Ra with a half-life of 1600 years. 226Ra occurs in the decay chain of 238U (often referred to as the radium series). Radium has 34 known isotopes from 201Ra to 234Ra.
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In the early history of the study of radioactivity, the different natural isotopes of radium were given different names, as it was not until Frederick Soddy's scientific career in the early 1900s that the concept of isotopes was realized.[3] In this scheme, 223Ra was named actinium X (AcX), 224Ra thorium X (ThX), 226Ra radium (Ra), and 228Ra mesothorium 1 (MsTh1).[4] When it was realized that all of these are isotopes of the same element, many of these names fell out of use, and "radium" came to refer to all isotopes, not just 226Ra,[5] though mesothorium 1 in particular was still used for some time, with a footnote explaining that it referred to 228Ra.[6] Some of radium-226's decay products received historical names including "radium",[7] ranging from radium A to radium G, with the letter indicating approximately how far they were down the chain from their parent 226Ra.[a]
In 2013 it was discovered that the nucleus of radium-224 is pear-shaped.[10] This was the first discovery of an asymmetrical nucleus.
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] | |||||||||||||||||||
| 201Ra[11] | 88 | 113 | 8 40 −4 ms |
α | 197Rn | (3/2−) | |||||||||||||
| 201mRa[12] | 260(30) keV | 1.6 7.7 −0.7 ms |
α | 197mRn | (13/2 ) | ||||||||||||||
| 202Ra | 88 | 114 | 202.00989(7) | 3.8 1.3 −0.8 ms[11] |
α | 198Rn | 0 | ||||||||||||
| 203Ra | 88 | 115 | 203.00927(9) | 4(3) ms | α | 199Rn | (3/2−) | ||||||||||||
| β (rare) | 203Fr | ||||||||||||||||||
| 203mRa | 220(90) keV | 41(17) ms | α | 199Rn | (13/2 ) | ||||||||||||||
| β (rare) | 203Fr | ||||||||||||||||||
| 204Ra | 88 | 116 | 204.006500(17) | 60(11) ms [59( 12−9) ms] |
α (99.7%) | 200Rn | 0 | ||||||||||||
| β (.3%) | 204Fr | ||||||||||||||||||
| 205Ra | 88 | 117 | 205.00627(9) | 220(40) ms [210( 60−40) ms] |
α | 201Rn | (3/2−) | ||||||||||||
| β (rare) | 205Fr | ||||||||||||||||||
| 205mRa | 310(110)# keV | 180(50) ms [170( 60−40) ms] |
α | 201Rn | (13/2 ) | ||||||||||||||
| IT (rare) | 205Ra | ||||||||||||||||||
| 206Ra | 88 | 118 | 206.003827(19) | 0.24(2) s | α | 202Rn | 0 | ||||||||||||
| 207Ra | 88 | 119 | 207.00380(6) | 1.3(2) s | α (90%) | 203Rn | (5/2−, 3/2−) | ||||||||||||
| β (10%) | 207Fr | ||||||||||||||||||
| 207mRa | 560(50) keV | 57(8) ms | IT (85%) | 207Ra | (13/2 ) | ||||||||||||||
| α (15%) | 203Rn | ||||||||||||||||||
| β (.55%) | 207Fr | ||||||||||||||||||
| 208Ra | 88 | 120 | 208.001840(17) | 1.3(2) s | α (95%) | 204Rn | 0 | ||||||||||||
| β (5%) | 208Fr | ||||||||||||||||||
| 208mRa | 1800(200) keV | 270 ns | (8 ) | ||||||||||||||||
| 209Ra | 88 | 121 | 209.00199(5) | 4.6(2) s | α (90%) | 205Rn | 5/2− | ||||||||||||
| β (10%) | 209Fr | ||||||||||||||||||
| 210Ra | 88 | 122 | 210.000495(16) | 3.7(2) s | α (96%) | 206Rn | 0 | ||||||||||||
| β (4%) | 210Fr | ||||||||||||||||||
| 210mRa | 1800(200) keV | 2.24 μs | (8 ) | ||||||||||||||||
| 211Ra | 88 | 123 | 211.000898(28) | 13(2) s | α (97%) | 207Rn | 5/2(−) | ||||||||||||
| β (3%) | 211Fr | ||||||||||||||||||
| 212Ra | 88 | 124 | 211.999794(12) | 13.0(2) s | α (85%) | 208Rn | 0 | ||||||||||||
| β (15%) | 212Fr | ||||||||||||||||||
| 212m1Ra | 1958.4(5) keV | 10.9(4) μs | (8) | ||||||||||||||||
| 212m2Ra | 2613.4(5) keV | 0.85(13) μs | (11)− | ||||||||||||||||
| 213Ra | 88 | 125 | 213.000384(22) | 2.74(6) min | α (80%) | 209Rn | 1/2− | ||||||||||||
| β (20%) | 213Fr | ||||||||||||||||||
| 213mRa | 1769(6) keV | 2.1(1) ms | IT (99%) | 213Ra | 17/2−# | ||||||||||||||
| α (1%) | 209Rn | ||||||||||||||||||
| 214Ra | 88 | 126 | 214.000108(10) | 2.46(3) s | α (99.94%) | 210Rn | 0 | ||||||||||||
| β (.06%) | 214Fr | ||||||||||||||||||
| 215Ra | 88 | 127 | 215.002720(8) | 1.55(7) ms | α | 211Rn | (9/2 )# | ||||||||||||
| 215m1Ra | 1877.8(5) keV | 7.1(2) μs | (25/2 ) | ||||||||||||||||
| 215m2Ra | 2246.9(5) keV | 1.39(7) μs | (29/2−) | ||||||||||||||||
| 215m3Ra | 3756.6(6) X keV | 0.555(10) μs | (43/2−) | ||||||||||||||||
| 216Ra | 88 | 128 | 216.003533(9) | 182(10) ns | α | 212Rn | 0 | ||||||||||||
| EC (<1×10−8%) | 216Fr | ||||||||||||||||||
| 217Ra | 88 | 129 | 217.006320(9) | 1.63(17) μs | α | 213Rn | (9/2 ) | ||||||||||||
| 218Ra | 88 | 130 | 218.007140(12) | 25.2(3) μs | α | 214Rn | 0 | ||||||||||||
| 219Ra | 88 | 131 | 219.010085(9) | 10(3) ms | α | 215Rn | (7/2) | ||||||||||||
| 220Ra | 88 | 132 | 220.011028(10) | 17.9(14) ms | α | 216Rn | 0 | ||||||||||||
| 221Ra | 88 | 133 | 221.013917(5) | 28(2) s | α | 217Rn | 5/2 | Trace[n 8] | |||||||||||
| CD (1.2×10−10%)[n 9] | 207Pb 14C | ||||||||||||||||||
| 222Ra | 88 | 134 | 222.015375(5) | 38.0(5) s | α | 218Rn | 0 | ||||||||||||
| CD (3×10−8%) | 208Pb 14C | ||||||||||||||||||
| 223Ra[n 10] | Actinium X | 88 | 135 | 223.0185022(27) | 11.43(5) d | α | 219Rn | 3/2 | Trace[n 11] | ||||||||||
| CD (6.4×10−8%) | 209Pb 14C | ||||||||||||||||||
| 224Ra | Thorium X | 88 | 136 | 224.0202118(24) | 3.6319(23) d | α | 220Rn | 0 | Trace[n 12] | ||||||||||
| CD (4.3×10−9%) | 210Pb 14C | ||||||||||||||||||
| 225Ra | 88 | 137 | 225.023612(3) | 14.9(2) d | β− | 225Ac | 1/2 | Trace[n 13] | |||||||||||
| α (2.0×10−3%)[2] | 221Rn | ||||||||||||||||||
| 226Ra | Radium[n 14] | 88 | 138 | 226.0254098(25) | 1600(7) y | α[n 15] | 222Rn | 0 | Trace[n 16] | ||||||||||
| CD (2.6×10−9%) | 212Pb 14C | ||||||||||||||||||
| 227Ra | 88 | 139 | 227.0291778(25) | 42.2(5) min | β− | 227Ac | 3/2 | ||||||||||||
| 228Ra | Mesothorium 1 | 88 | 140 | 228.0310703(26) | 5.75(3) y | β− | 228Ac | 0 | Trace[n 12] | ||||||||||
| 229Ra | 88 | 141 | 229.034958(20) | 4.0(2) min | β− | 229Ac | 5/2( ) | ||||||||||||
| 230Ra | 88 | 142 | 230.037056(13) | 93(2) min | β− | 230Ac | 0 | ||||||||||||
| 231Ra | 88 | 143 | 231.04122(32)# | 103(3) s | β− | 231Ac | (5/2 ) | ||||||||||||
| 231mRa | 66.21(9) keV | ~53 μs | (1/2 ) | ||||||||||||||||
| 232Ra | 88 | 144 | 232.04364(30)# | 250(50) s | β− | 232Ac | 0 | ||||||||||||
| 233Ra | 88 | 145 | 233.04806(50)# | 30(5) s | β− | 233Ac | 1/2 # | ||||||||||||
| 234Ra | 88 | 146 | 234.05070(53)# | 30(10) s | β− | 234Ac | 0 | ||||||||||||
| This table header & footer: | |||||||||||||||||||
- ^ mRa – 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 symbol as daughter – Daughter product is 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).
- ^ Intermediate decay product of 237Np
- ^ Lightest known nuclide to undergo cluster decay
- ^ Used for treating bone cancer
- ^ Intermediate decay product of 235U
- ^ a b Intermediate decay product of 232Th
- ^ Intermediate decay product of 237Np
- ^ Source of element's name
- ^ Theoretically capable of β-β- decay to 226Th[1]
- ^ Intermediate decay product of 238U
Actinides vs fission products
edit| Actinides[13] by decay chain | Half-life range (a) |
Fission products of 235U by yield[14] | ||||||
|---|---|---|---|---|---|---|---|---|
| 4n | 4n 1 | 4n 2 | 4n 3 | 4.5–7% | 0.04–1.25% | <0.001% | ||
| 228Ra№ | 4–6 a | 155Euþ | ||||||
| 248Bk[15] | > 9 a | |||||||
| 244Cmƒ | 241Puƒ | 250Cf | 227Ac№ | 10–29 a | 90Sr | 85Kr | 113mCdþ | |
| 232Uƒ | 238Puƒ | 243Cmƒ | 29–97 a | 137Cs | 151Smþ | 121mSn | ||
| 249Cfƒ | 242mAmƒ | 141–351 a |
No fission products have a half-life | |||||
| 241Amƒ | 251Cfƒ[16] | 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₡ | |||||
| 1.33 Ma | 135Cs₡ | |||||||
| 237Npƒ | 1.61–6.5 Ma | 93Zr | 107Pd | |||||
| 236U | 247Cmƒ | 15–24 Ma | 129I₡ | |||||
| 244Pu | 80 Ma |
... nor beyond 15.7 Ma[17] | ||||||
| 232Th№ | 238U№ | 235Uƒ№ | 0.7–14.1 Ga | |||||
| ||||||||
References
edit- ^ a b 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.
- ^ a b Liang, C. F.; Paris, P.; Sheline, R. K. (2000-09-19). "α decay of 225Ra". Physical Review C. 62 (4). American Physical Society (APS): 047303. Bibcode:2000PhRvC..62d7303L. doi:10.1103/physrevc.62.047303. ISSN 0556-2813.
- ^ Nagel, Miriam C. (September 1982). "Frederick Soddy: From alchemy to isotopes". Journal of Chemical Education. 59 (9): 739. Bibcode:1982JChEd..59..739N. doi:10.1021/ed059p739. ISSN 0021-9584.
- ^ Kirby, H.W. & Salutsky, Murrell L. (December 1964). The Radiochemistry of Radium (Report). crediting UNT Libraries Government Documents Department. p. 3 – via University of North Texas, UNT Digital Library. Alternate source: https://sgp.fas.org/othergov/doe/lanl/lib-www/books/rc000041.pdf
- ^ Giunta, Carmen J. (2017). "ISOTOPES: IDENTIFYING THE BREAKTHROUGH PUBLICATION (1)" (PDF). Bull. Hist. Chem. 42 (2): 103–111.
- ^ Looney, William B. (1958). "Effects of Radium in Man". Science. 127 (3299): 630–633. Bibcode:1958Sci...127..630L. doi:10.1126/science.127.3299.630. ISSN 0036-8075. JSTOR 1755774. PMID 13529029.
- ^ Mitchell, S. A. "Is Radium in the Sun?". Popular Astronomy. 21: 321–331. Bibcode:1913PA.....21..321M.
- ^ Kuhn, W. (1929). "LXVIII. Scattering of thorium C" γ-radiation by radium G and ordinary lead". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. 8 (52): 628. doi:10.1080/14786441108564923. ISSN 1941-5982.C" γ-radiation by radium G and ordinary lead&rft.volume=8&rft.issue=52&rft.pages=628&rft.date=1929&rft_id=info:doi/10.1080/14786441108564923&rft.issn=1941-5982&rft.aulast=Kuhn&rft.aufirst=W.&rfr_id=info:sid/en.wikipedia.org:Isotopes of radium" class="Z3988">
- ^ Kinsey, R. R. (December 18, 1997), "The radioactive series of radium-226" (PDF), The NUDAT/PCNUDAT Program for Nuclear Data – via CERN
- ^ Hills, Stephanie (8 May 2013). "First observations of short-lived pear-shaped atomic nuclei". CERN.
- ^ a b Kalaninová, Z.; Antalic, S.; Andreyev, A. N.; Heßberger, F. P.; Ackermann, D.; Andel, B.; Bianco, L.; Hofmann, S.; Huyse, M.; Kindler, B.; Lommel, B.; Mann, R.; Page, R. D.; Sapple, P. J.; Thomson, J.; Van Duppen, P.; Venhart, M. (12 May 2014). "Decay of 201–203Ra and 200–202Fr" (PDF). Physical Review C. 89 (5): 054312. Bibcode:2014PhRvC..89e4312K. doi:10.1103/PhysRevC.89.054312. ISSN 0556-2813. Retrieved 11 June 2023.
- ^ Uusitalo, J.; Leino, M.; Enqvist, T.; Eskola, K.; Grahn, T.; Greenlees, P. T.; Jones, P.; Julin, R.; Juutinen, S.; Keenan, A.; Kettunen, H.; Koivisto, H.; Kuusiniemi, P.; Leppänen, A.-P.; Nieminen, P.; Pakarinen, J.; Rahkila, P.; Scholey, C. (11 February 2005). "α decay studies of very neutron-deficient francium and radium isotopes". Physical Review C. 71 (2): 024306. Bibcode:2005PhRvC..71b4306U. doi:10.1103/PhysRevC.71.024306. ISSN 0556-2813.
- ^ 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.
- 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.