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All atomic nuclei of the chemical element protactinium are summarized under protactinium isotopes; these all consist of an atomic nucleus with 91 protons and, in the uncharged state, 91 electrons. The difference between each protactinium isotope is based on the number of neutrons in the nucleus.
Natural terrestrial protactinium deposits consist practically 100% of the nuclide 231Pa; in addition, the isotope 234Pa and its nuclear isomeric nuclide 234mPa are found in small traces and as intermediate products of radioactive decay processes. All protactinium isotopes are unstable.
The relative atomic mass is given as 231.03588(2) u.
Isotope Nuclide | E | N | Atomic Mass [Nuclear Mass] {Mass Excess} | Spin I (h/2π) | Parent |
---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 |
Protactinium-212 | 21291Pa | 121 | 212.02318(8) u [211.9732657 u] {21.59203 MeV} | ||
Protactinium-213 | 21391Pa | 122 | 213.02111(8) u [212.9711957 u] {19.66384 MeV} | ||
Protactinium-214 | 21491Pa | 123 | 214.02092(8) u [213.9710057 u] {19.48685 MeV} | ||
Protactinium-215 | 21591Pa | 124 | 215.01918(8) u [214.9692657 u] {17.86605 MeV} | ||
Protactinium-216 | 21691Pa | 125 | 216.01911(6) u [215.9691957 u] {17.80085 MeV} | ||
Protactinium-217 | 21791Pa | 126 | 217.018324(17) u [216.9684097 u] {17.0687 MeV} | (9/2-) | |
Protactinium-217m | 217m91Pa | 126 | 217.018324(17) u [216.9684097 u] {17.0687 MeV} | (23/2-) | |
Protactinium-218 | 21891Pa | 127 | 218.020058(20) u [217.9701437 u] {18.68391 MeV} | ||
Protactinium-219 | 21991Pa | 128 | 219.01990(6) u [218.9699857 u] {18.53673 MeV} | 9/2- | |
Protactinium-220 | 22091Pa | 129 | 220.02170(5) u [219.9717857 u] {20.21342 MeV} | ||
Protactinium-221 | 22191Pa | 130 | 221.02187(6) u [220.9719557 u] {20.37177 MeV} | 9/2- | |
Protactinium-222 | 22291Pa | 131 | 222.02378(8) u [221.9738657 u] {22.15093 MeV} | 226Np | |
Protactinium-223 | 22391Pa | 132 | 223.02396(8) u [222.9740457 u] {22.3186 MeV} | 227Np | |
Protactinium-224 | 22491Pa | 133 | 224.025617(8) u [223.9757027 u] {23.86208 MeV} | (5-) | 228Np |
Protactinium-225 | 22591Pa | 134 | 225.026150(90) u [224.9762357 u] {24.35857 MeV} | 229Np | |
Protactinium-226 | 22691Pa | 135 | 226.027948(12) u [225.9780337 u] {26.03339 MeV} | 230Np | |
Protactinium-227 | 22791Pa | 136 | 227.028804(8) u [226.9788897 u] {26.83075 MeV} | (5/2-) | 231Np |
Protactinium-228 | 22891Pa | 137 | 228.031051(5) u [227.9811367 u] {28.92382 MeV} | 3+ | 232Np |
Protactinium-229 | 22991Pa | 138 | 229.032096(4) u [228.9821817 u] {29.89723 MeV} | (5/2+) | 233Np 229U |
Protactinium-230 | 23091Pa | 139 | 230.034540(3) u [229.9846257 u] {32.1738 MeV} | 2- | |
Protactinium-231 | 23191Pa | 140 | 231.0358826(19) u [230.9859683 u] {33.42443 MeV} | 3/2- | 235Np 231U 231Th |
Protactinium-232 | 23291Pa | 141 | 232.038590(8) u [231.9886757 u] {35.94635 MeV} | (2-) | 236Np |
Protactinium-233 | 23391Pa | 142 | 233.0402466(14) u [232.9903323 u] {37.48947 MeV} | 3/2- | 237Np 233Th |
Protactinium-234 | 23491Pa | 143 | 234.043306(4) u [233.9933917 u] {40.33928 MeV} | 4+ | 234Th |
Protactinium-234m | 234m91Pa | 143 | 234.043306(4) u [233.9933917 u] {40.33928 MeV} | (0-) | |
Protactinium-235 | 23591Pa | 144 | 235.045399(15) u [234.9954847 u] {42.2889 MeV} | (3/2-) | 235Th |
Protactinium-236 | 23691Pa | 145 | 236.048668(15) u [235.9987537 u] {45.33395 MeV} | 1(+) | 236Th |
Protactinium-237 | 23791Pa | 146 | 237.051023(14) u [237.0011087 u] {47.52762 MeV} | (1/2+) | |
Protactinium-238 | 23891Pa | 147 | 238.054637(17) u [238.0047227 u] {50.89404 MeV} | (3-) | 238Th |
Protactinium-239 | 23991Pa | 148 | 239.05726(21) u [239.0073457 u] {53.33735 MeV} | (3/2) | |
Protactinium-240 | 24091Pa | 149 |
Isotope | Radioactive Decay | Extern | |||
---|---|---|---|---|---|
Half-life | Decay Mode | Probability | Energy | ||
7 | 8 | 9 | 10 | 11 | 12 |
Pa-212 | ca. 5.1 ms | α → 208Ac | 100 % | 8.42(5) MeV | AL |
Pa-213 | ca. 5.3 ms | α → 209Ac | 100 % | 8.39(5) MeV | AL |
Pa-214 | 17(3) ms | α → 210Ac | ≤ 100 % | 8.27(5) MeV | AL |
Pa-215 | 14(2) ms | α → 211Ac | 100 % | 8.24(5) MeV | AL |
Pa-216 | ca. 0.15 s | α → 212Ac EC → 216Th | ~ 98 % ~ 2 % | 8.097(15) MeV 7.50(5) MeV | AL |
Pa-217 | 3.8(2) ms | α → 213Ac | 100 % | 8.489(4) MeV | AL |
Pa-217m | 1.08(3) ms | α → 213Ac Iso → 217Pa | 73(4) % 27(4) % | AL | |
Pa-218 | 113(10) μs | α → 214Ac | 100 % | 9.815(10) MeV | AL |
Pa-219 | 53(10) ns | α → 215Ac | 100 % | 10.08(5) MeV | AL |
Pa-220 | 0.78(16) μs | α → 216Ac EC/β+ → 220Th | > 99 % << 1 % | 9.65(5) MeV 5.55(6) MeV | AL |
Pa-221 | 5.9(17) μs | α → 217Ac | 100 % | 9.25(5) MeV | AL |
Pa-222 | ca. 2.9 ms | α → 218Ac | 100 % | 8.89(5) MeV | AL |
Pa-223 | 5.1(6) ms | α → 219Ac | 100 % | 8.33(5) MeV | AL |
Pa-224 | 846(20) ms | α → 220Ac | 100 % | 7.694(6) MeV | AL |
Pa-225 | 1.7(2) s | α → 221Ac | 100 % | 7.401(59) MeV | AL |
Pa-226 | 1.8(2) min | α → 222Ac EC/β+ → 226Th | 74(5) % 26(5) % | 6.987(10) MeV 2.836(12) MeV | AL |
Pa-227 | 38.3(3) min | α → 223Ac EC → 227Th | 85(2) % 15(2) % | 6.5804(21) MeV 1.026(8) MeV | AL |
Pa-228 | 22(1) h | α → 224Ac EC/β+ → 228Th | 1.85(17) % 98.15(17) % | 6.2645(15) MeV 2.153(5) MeV | AL |
Pa-229 | 1.50(5) d | α → 225Ac EC → 229Th | 0.48(5) % 99.52(5) % | 5.835(4) MeV 0.311(4) MeV | AL |
Pa-230 | 17.4(5) d | α → 226Ac EC/β+ → 230Th β- → 230U | 0.0032(1) % 92.2(7) % 7.8(7) % | 5.4394(7) MeV 1.311(3) MeV 0.559(5) MeV | AL |
Pa-231 | 3.276(11) × 104 a | α → 227Ac SF div | ca. 100 % <<< 1 % | 5.1499(8) MeV | AL |
Pa-232 | 1.32(2) d | β- → 232U EC → 232Th | ca. 100 % ? | 1.337(7) MeV 0.500(8) MeV | AL |
Pa-233 | 26.975(13) d | β- → 233U | 100 % | 0.5703(20) MeV | AL |
Pa-234 | 6.70(5) h | β- → 234U | 100 % | 2.194(4) MeV | AL |
Pa-234m | 1.159(11) min | β- → 234U Iso → 234Pa | 99.84(4) % 0.16(4) % | AL | |
Pa-235 | 24.4(2) min | β- → 235U | 100 % | 1.370(14) MeV | AL |
Pa-236 | 9.1(1) min | β- → 236U | 100 % | 2.889(14) MeV | AL |
Pa-237 | 8.7(2) min | β- → 237U | 100 % | 2.137(13) MeV | AL |
Pa-238 | 2.28(10) min | β- → 238U | 100 % | 3.586(16) MeV | AL |
Pa-239 | 1.8(5) h | β- → 239U | 100 % | 2.76(20) MeV | AL |
Pa-240 | - ungelistet - | 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 Protactinium 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 Protactinium 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) |
---|---|---|---|---|
231Pa 100 % 3/2- | 2,01(2) | 0,40 {-1,72(5)} | 10,2 | 0,06903 1,1995 |
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 Protactinium radionuclides:
Nuclide | Limit Value | HASS limit | SC | Daughter Nuclides | Half-life | |
---|---|---|---|---|---|---|
Pa-227+ | 106 Bq | 1000 Bq/g | 38.3 min | |||
Pa-228+ | 106 Bq | 10 Bq/g | 22.0 h | |||
Pa-230+ | 106 Bq | 10 Bq/g | 0,1 TBq | 1 Bq cm-2 | 17.4 d | |
Pa-231 | 103 Bq | 0,01 Bq/g | 0,01 Bq cm-2 | 33000 a | ||
Pa-232 | 106 Bq | 10 Bq/g | 1.3 d | |||
Pa-233 | 107 Bq | 10 Bq/g | 0,4 TBq | 10 Bq cm-2 | 27.0 d | |
Pa-234 | 106 Bq | 10 Bq/g | 6.8 h |
(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)
Properties of the Protactinium 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.
Protactinium: NMR properties - 231Pa-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: 2022-12-12
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