More Chemistry
All atomic nuclei of the chemical element thorium are summarized under thorium isotopes; these all consist of an atomic nucleus with 90 protons and, in the uncharged state, 90 electrons. The difference between the individual thorium isotopes is based on the number of neutrons in the nucleus.
Terrestrial thorium deposits consist of practically 99.98% of the nuclide 232Th and 0 .02% from 230Th; in addition, the 4 isotopes 227Th, 228Th, 231Th and 234Th and 234 are found in small traces and as intermediate products of radioactive decay processes. sup>Th.
Thorium isotopes are used in various fields. In the nuclear energy industry, for example, they are used as fuel in so-called thorium fuel cells. In medical diagnostics, thorium isotopes can be used to produce imaging agents. They can also be used in the manufacture of ceramics and glasses as they increase the hardness and durability of these materials.
However, it is important to note that all thorium isotopes are radioactive and therefore appropriate precautions must be taken in use and handling to protect the health and safety of people and the environment.
The relative atomic mass is given as 232.0377(4) u.
Newly discovered or observed thorium isotopes: Th-207 (2022).
Isotope Nuclide | E | N | Atomic Mass [Nuclear Mass] {Mass Excess} | Spin I (h/2π) | Parent |
---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 |
Thorium-207 | 20790Th | 117 | 207 u [206.9506342 u] {0 MeV} | ||
Thorium-208 | 20890Th | 118 | 208.01791(4) u [207.9685442 u] {16.68306 MeV} | 0+ | |
Thorium-209 | 20990Th | 119 | 209.01757(15) u [208.9682042 u] {16.36635 MeV} | (13/2+) | |
Thorium-210 | 21090Th | 120 | 210.015093(20) u [209.9657272 u] {14.05904 MeV} | 0+ | |
Thorium-211 | 21190Th | 121 | 211.01493(8) u [210.9655642 u] {13.90721 MeV} | ||
Thorium-212 | 21290Th | 122 | 212.013001(11) u [211.9636352 u] {12.11035 MeV} | 0+ | |
Thorium-213 | 21390Th | 123 | 213.013011(10) u [212.9636452 u] {12.11967 MeV} | (5/2-) | 217U |
Thorium-214 | 21490Th | 124 | 214.011481(11) u [213.9621152 u] {10.69448 MeV} | 0+ | 218U |
Thorium-214m | 214m90Th | 124 | 214.011481(11) u [213.9621152 u] {10.69448 MeV} | (8+) | |
Thorium-215 | 21590Th | 125 | 215.011725(9) u [214.9623592 u] {10.92177 MeV} | (1/2-) | 219U |
Thorium-215m | 215m90Th | 125 | 215.011725(9) u [214.9623592 u] {10.92177 MeV} | ||
Thorium-216 | 21690Th | 126 | 216.011056(13) u [215.9616902 u] {10.2986 MeV} | 0+ | |
Thorium-216m1 | 216m190Th | 126 | 216.011056(13) u [215.9616902 u] {10.2986 MeV} | 8+ | |
Thorium-216m2 | 216m290Th | 126 | 216.011056(13) u [215.9616902 u] {10.2986 MeV} | 11- | |
Thorium-216m3 | 216m390Th | 126 | 216.011056(13) u [215.9616902 u] {10.2986 MeV} | (14+) | |
Thorium-217 | 21790Th | 127 | 217.013103(11) u [216.9637372 u] {12.20537 MeV} | (9/2+) | 221U |
Thorium-217m1 | 217m190Th | 127 | 217.013103(11) u [216.9637372 u] {12.20537 MeV} | (15/2-) | |
Thorium-218 | 21890Th | 128 | 218.013276(11) u [217.9639102 u] {12.36651 MeV} | 0+ | 222U |
Thorium-219 | 21990Th | 129 | 219.01554(5) u [218.9661742 u] {14.47542 MeV} | (9/2+) | 223U |
Thorium-220 | 22090Th | 130 | 220.015748(24) u [219.9663822 u] {14.66917 MeV} | 0+ | 224U |
Thorium-221 | 22190Th | 131 | 221.018186(9) u [220.9688202 u] {16.94015 MeV} | (7/2+) | 225U |
Thorium-222 | 22290Th | 132 | 222.018468(13) u [221.9691022 u] {17.20283 MeV} | 0+ | 226U |
Thorium-223 | 22390Th | 133 | 223.020811(9) u [222.9714452 u] {19.38532 MeV} | (5/2)+ | 227U |
Thorium-224 | 22490Th | 134 | 224.021464(11) u [223.9720982 u] {19.99359 MeV} | 0+ | 228U |
Thorium-225 | 22590Th | 135 | 225.023951(5) u [224.9745852 u] {22.31021 MeV} | (3/2+) | 229U |
Thorium-226 | 22690Th | 136 | 226.024904(5) u [225.9755382 u] {23.19793 MeV} | 0+ | 230U 226Ac 226Pa |
Thorium-227 | 22790Th | 137 | 227.0277025(22) u [226.9783367 u] {25.80471 MeV} | (1/2+) | 231U 227Ac 227Pa |
Thorium-228 | 22890Th | 138 | 228.0287398(19) u [227.979374 u] {26.77095 MeV} | 0+ | 232U 228Ac 228Pa |
Thorium-229 | 22990Th | 139 | 229.0317614(26) u [228.9823956 u] {29.58555 MeV} | 5/2+ | 233U 229Ac |
Thorium-229m | 229m90Th | 139 | 229.0317614(26) u [228.9823956 u] {29.58555 MeV} | 3/2+ | |
Thorium-230 | 23090Th | 140 | 230.0331323(2) u [229.9837665 u] {30.86254 MeV} | 0+ | 234U 230Ac 230Pa |
Thorium-231 | 23190Th | 141 | 231.0363028(13) u [230.986937 u] {33.81584 MeV} | 5/2+ | 235U 231Ac |
Thorium-232 | 23290Th | 142 | 232.03806(2) u [231.9886942 u] {35.45266 MeV} | 0+ | 236U 232Ac 232Pa |
Thorium-233 | 23390Th | 143 | 233.0415802(15) u [232.9922144 u] {38.73171 MeV} | 1/2+ | 233Ac |
Thorium-234 | 23490Th | 144 | 234.0435999(28) u [233.9942341 u] {40.61305 MeV} | 0+ | 238U 234Ac |
Thorium-235 | 23590Th | 145 | 235.047255(14) u [234.9978892 u] {44.01775 MeV} | (1/2+) | |
Thorium-236 | 23690Th | 146 | 236.049657(15) u [236.0002912 u] {46.2552 MeV} | 0+ | |
Thorium-237 | 23790Th | 147 | 237.053629(17) u [237.0042632 u] {49.95509 MeV} | (5/2+) | |
Thorium-238 | 23890Th | 148 | 238.05639(30) u [238.0070242 u] {52.52695 MeV} | 0+ |
Isotope | Radioactive Decay | Extern | |||
---|---|---|---|---|---|
Half-life | Decay Mode | Probability | Energy | ||
7 | 8 | 9 | 10 | 11 | 12 |
Th-207 | 0.0097 s | α → 203Ra | 8.167(21) MeV | AL | |
Th-208 | 1.7 ms | α → 204Ra | 100 % | 8.20(3) MeV | AL |
Th-209 | 2.5 ms | α → 205Ra | 8.10(14) MeV | AL | |
Th-210 | 1.6(4) ms | α → 206Ra EC/β+ → 210Ac | 99 % ca. 1 % | 8.069(6) MeV 5.27(6) MeV | AL |
Th-211 | 37 ms | α → 207Ra &epsilon → 211Ac | ? ? | 7.94(5) MeV 6.71(9) MeV | AL |
Th-212 | 31.7(13) ms | α → 208Ra EC/β+ → 212Ac | ca. 99.7 % ca. 0.3 % | 7.958(5) MeV 4.83(5) MeV | AL |
Th-213 | 144(21) ms | α → 209Ra | ≤ 100 % | 7.837(7) MeV | AL |
Th-214 | 87(10) ms | α → 210Ra | 100 % | 7.827(5) MeV | AL |
Th-214m | 1.24(12) μs | Iso → 214Th | 100 % | ||
Th-215 | 1.2(2) s | α → 211Ra | 100 % | 7.665(4) MeV | AL |
Th-215m | 0.77(6) μs | Iso → 215Th | 100 % | ||
Th-216 | 26.0(2) ms | α → 212Ra | ≤ 100 % | 8.072(4) MeV | AL |
Th-216m1 | 134(4) μs | α → 212Ra | 2.8(9) % | ||
Th-216m2 | 0.58(3) μs | ||||
Th-216m3 | 0.74(7) μs | ||||
Th-217 | 0.252(4) ms | α → 213Ra | 100 % | 9.435(4) MeV | AL |
Th-217m1 | 0.141(50) ms | Iso → 217Th | 100 % | AL | |
Th-218 | 117(9) ns | α → 214Ra | 100 % | 9.849(9) MeV | AL |
Th-219 | 1.05(3) μs | α → 215Ra | 100 % | 9.51(5) MeV | AL |
Th-220 | 9.7(6) μs | α → 216Ra EC → 220Ac | ≤ 100 % << 1 % | 8.953(20) MeV 0.925(23) MeV | AL |
Th-221 | 1.74(3) ms | α → 217Ra | 100 % | 8.625(4) MeV | AL |
Th-222 | 2.24(3) ms | α → 218Ra | 100 % | 8.127(5) MeV | AL |
Th-223 | 0.60(2) s | α → 219Ra | 100 % | 7.567(4) MeV | AL |
Th-224 | 1.04(2) s | α → 220Ra | 100 % | 7.299(6) MeV | AL |
Th-225 | 8.75(4) min | α → 221Ra EC → 225Ac | ca. 90 % ca. 10 % | 6.9214(21) MeV 0.637(7) MeV | AL |
Th-226 | 30.57(10) min | α → 222Ra | 100 % | 6.4525(10) MeV | AL |
Th-227 | 18.697(7) d | α → 223Ra | 100 % | 6.1466(1) MeV | AL |
Th-228 | 1.9116(16) a | α → 224Ra | 100 % | 5.52015(22) MeV | AL |
Th-229 | 7880(120) a | α → 225Ra | 100 % | 5.1676(10) MeV | AL |
Th-229m | 7(1) μs | Iso → 229Th | |||
Th-230 | 7.54(3) × 104 a | α → 226Ra SF div CD → 24Ne | ca. 100 % << 1 % << 1 % | 4.7700(15) MeV | AL |
Th-231 | 25.57(8) h | β- → 231Pa | 100 % | 3.915(15) MeV | AL |
Th-232 | 1.40(1) × 1010 a | α → 228Ra SF div | > 99 % << 1 % | 4.0816(14) MeV | AL |
Th-233 | 21.83(4) min | β- → 233Pa | 100 % | 1.2422(11) MeV | AL |
Th-234 | 24.10(3) d | β- → 234Pa | 100 % | 0.274(3) MeV | AL |
Th-235 | 7.2(1) min | β- → 235Pa | 100 % | 1.729(19) MeV | AL |
Th-236 | 37.5(2) min | β- → 236Pa | 100 % | 0.921(20) MeV | AL |
Th-237 | 4.8(5) min | β- → 237Pa | 100 % | 2.427(21) MeV | AL |
Th-238 | 9.4(20) min | β- → 238Pa | 100 % | 1.63(28) 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 Thorium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 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 Thorium 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.
Nuclide quantity 1) spin | Nuclear magnetic moment μ/μN | Gyromagnetic ratio {Quadrupole moment} | Resonant frequency v0 bei 1 T | Relative sensitivity H0 = const. v0 = const. 3) |
---|---|---|---|---|
229Th 5/2+ | + 0,46(4) | 0,40 {3,110(6)} | 1,40 | 0,00042 0,3843 |
1) Quantity Percentage of natural occurrence.
2) Gyromagnetic ratio: 107 rad T-1 s-1
Quadrupole moment: Q [barn] = [100 fm2]
3) Related to 1H = 1,000.
According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Thorium radionuclides:
Nuclide | Limit Value | HASS limit | SC | Daughter Nuclides | Half-life | |
---|---|---|---|---|---|---|
Th-226+ | 107 Bq | 1000 Bq/g | 10 Bq cm-2 | Ra-222, Rn-218, Po-214 | 30.6 min | |
Th-227 | 104 Bq | 10 Bq/g | 0,1 Bq cm-2 | 18.7 d | ||
Th-228+ | 104 Bq | 0,1 Bq/g | 0,04 TBq | 0,1 Bq cm-2 | Ra-224, Rn-220, Po-216, Pb-212, Bi-212, Tl-208, Po-212 | 1.9 a |
Th-229+ | 103 Bq | 0,1 Bq/g | 0,01 TBq | 0,1 Bq cm-2 | Ra-225, Ac-225, Fr-221, At-217, Bi-213, Tl-209, Po-213, Pb-209 | 7300 a |
Th-230 | 104 Bq | 0,1 Bq/g | 0,1 Bq cm-2 | 75000 a | ||
Th-231 | 107 Bq | 1000 Bq/g | 10 TBq | 100 Bq cm-2 | 25.5 h | |
Th-232 | 104 Bq | 10 Bq/g | 0,1 Bq cm-2 | 1.4 × 1010 a | ||
Th234+ | 105 Bq | 100 Bq/g | 2 TBq | 100 Bq cm-2 | Pa-234m, Pa-234 | 24.1 d |
(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)
Properties of the Thorium 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.
Thorium: NMR properties - 229Th-NMR
[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.
[9] - C. Fry, M. Thoennessen:
Discovery of actinium, thorium, protactinium, and uranium isotopes.
In: Atomic Data and Nuclear Data Tables, (2013), DOI 10.1016/j.adt.2012.03.002.
Last update: 2022-12-16
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