Isotopes of gadolinium
Naturally occurring gadolinium (Gd) is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and 1 radioisotope, 152Gd, with 158Gd being the most abundant (24.84% natural abundance). The predicted double beta decay of 160Gd has never been observed; only lower limit on its half-life of more than 1.3×1021 years has been set experimentally.[1]
Thirty radioisotopes have been characterized, with the most stable being alpha-decaying 152Gd (naturally occurring) with a half-life of 1.08×1014 years, and 150Gd with a half-life of 1.79×106 years. All of the remaining radioactive isotopes have half-lives less than 74.7 years. The majority of these have half-lives less than 24.6 seconds. Gadolinium isotopes have 10 metastable isomers, with the most stable being 143mGd (t1/2=110 seconds), 145mGd (t1/2=85 seconds) and 141mGd (t1/2=24.5 seconds).
The primary decay mode at atomic weights lower than the most abundant stable isotope, 158Gd, is electron capture, and the primary mode at higher atomic weights is beta decay. The primary decay products for isotopes of weights lower than 158Gd are the element Eu (europium) isotopes and the primary products at higher weights are the element Tb (terbium) isotopes.
Gadolinium-153 has a half-life of 240.4±10 days and emits gamma radiation with strong peaks at 41 keV and 102 keV. It is used as a gamma ray source in X-ray absorptiometry or bone density gauges for osteoporosis screening, and for radiometric profiling in the Lixiscope portable x-ray imaging system, also known as the Lixi Profiler.
Standard atomic mass: 157.25(3) u
Table
nuclide symbol |
Z(p) | N(n) | isotopic mass (u) |
half-life[n 1] | decay mode(s)[2][n 2] |
daughter isotope(s)[n 3] |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
---|---|---|---|---|---|---|---|---|---|
excitation energy | |||||||||
134Gd | 64 | 70 | 133.95537(43)# | 0.4# s | 0+ | ||||
135Gd | 64 | 71 | 134.95257(54)# | 1.1(2) s | 3/2- | ||||
136Gd | 64 | 72 | 135.94734(43)# | 1# s [>200 ns] | β+ | 136Eu | |||
137Gd | 64 | 73 | 136.94502(43)# | 2.2(2) s | β+ | 137Eu | 7/2+# | ||
β+, p (rare) | 136Sm | ||||||||
138Gd | 64 | 74 | 137.94012(21)# | 4.7(9) s | β+ | 138Eu | 0+ | ||
138mGd | 2232.7(11) keV | 6(1) µs | (8-) | ||||||
139Gd | 64 | 75 | 138.93824(21)# | 5.7(3) s | β+ | 139Eu | 9/2-# | ||
β+, p (rare) | 138Sm | ||||||||
139mGd | 250(150)# keV | 4.8(9) s | 1/2+# | ||||||
140Gd | 64 | 76 | 139.93367(3) | 15.8(4) s | β+ | 140Eu | 0+ | ||
141Gd | 64 | 77 | 140.932126(21) | 14(4) s | β+ (99.97%) | 141Eu | (1/2+) | ||
β+, p (.03%) | 140Sm | ||||||||
141mGd | 377.8(2) keV | 24.5(5) s | β+ (89%) | 141Eu | (11/2-) | ||||
IT (11%) | 141Gd | ||||||||
142Gd | 64 | 78 | 141.92812(3) | 70.2(6) s | β+ | 142Eu | 0+ | ||
143Gd | 64 | 79 | 142.92675(22) | 39(2) s | β+ | 143Eu | (1/2)+ | ||
β+, α (rare) | 139Pm | ||||||||
β+, p (rare) | 142Sm | ||||||||
143mGd | 152.6(5) keV | 110.0(14) s | β+ | 143Eu | (11/2-) | ||||
β+, α (rare) | 139Pm | ||||||||
β+, p (rare) | 142Sm | ||||||||
144Gd | 64 | 80 | 143.92296(3) | 4.47(6) min | β+ | 144Eu | 0+ | ||
145Gd | 64 | 81 | 144.921709(20) | 23.0(4) min | β+ | 145Eu | 1/2+ | ||
145mGd | 749.1(2) keV | 85(3) s | IT (94.3%) | 145Gd | 11/2- | ||||
β+ (5.7%) | 145Eu | ||||||||
146Gd | 64 | 82 | 145.918311(5) | 48.27(10) d | EC | 146Eu | 0+ | ||
147Gd | 64 | 83 | 146.919094(3) | 38.06(12) h | β+ | 147Eu | 7/2- | ||
147mGd | 8587.8(4) keV | 510(20) ns | (49/2+) | ||||||
148Gd | 64 | 84 | 147.918115(3) | 74.6(30) a | α | 144Sm | 0+ | ||
β+β+ (rare) | 148Sm | ||||||||
149Gd | 64 | 85 | 148.919341(4) | 9.28(10) d | β+ | 149Eu | 7/2- | ||
α (4.34×10−4%) | 145Sm | ||||||||
150Gd | 64 | 86 | 149.918659(7) | 1.79(8)×106 a | α | 146Sm | 0+ | ||
β+β+ (rare) | 150Sm | ||||||||
151Gd | 64 | 87 | 150.920348(4) | 124(1) d | EC | 151Eu | 7/2- | ||
α (10−6%) | 147Sm | ||||||||
152Gd[n 4] | 64 | 88 | 151.9197910(27) | 1.08(8)×1014 a | α | 148Sm | 0+ | 0.0020(1) | |
153Gd | 64 | 89 | 152.9217495(27) | 240.4(10) d | EC | 153Eu | 3/2- | ||
153m1Gd | 95.1737(12) keV | 3.5(4) µs | (9/2+) | ||||||
153m2Gd | 171.189(5) keV | 76.0(14) µs | (11/2-) | ||||||
154Gd | 64 | 90 | 153.9208656(27) | Observationally Stable[n 5] | 0+ | 0.0218(3) | |||
155Gd[n 6] | 64 | 91 | 154.9226220(27) | Observationally Stable[n 7] | 3/2- | 0.1480(12) | |||
155mGd | 121.05(19) keV | 31.97(27) ms | IT | 155Gd | 11/2- | ||||
156Gd[n 6] | 64 | 92 | 155.9221227(27) | Stable[n 8] | 0+ | 0.2047(9) | |||
156mGd | 2137.60(5) keV | 1.3(1) µs | 7- | ||||||
157Gd[n 6] | 64 | 93 | 156.9239601(27) | Stable[n 8] | 3/2- | 0.1565(2) | |||
158Gd[n 6] | 64 | 94 | 157.9241039(27) | Stable[n 8] | 0+ | 0.2484(7) | |||
159Gd[n 6] | 64 | 95 | 158.9263887(27) | 18.479(4) h | β− | 159Tb | 3/2- | ||
160Gd[n 6] | 64 | 96 | 159.9270541(27) | Observationally Stable[n 9] | 0+ | 0.2186(19) | |||
161Gd | 64 | 97 | 160.9296692(29) | 3.646(3) min | β− | 161Tb | 5/2- | ||
162Gd | 64 | 98 | 161.930985(5) | 8.4(2) min | β− | 162Tb | 0+ | ||
163Gd | 64 | 99 | 162.93399(32)# | 68(3) s | β− | 163Tb | 7/2+# | ||
164Gd | 64 | 100 | 163.93586(43)# | 45(3) s | β− | 164Tb | 0+ | ||
165Gd | 64 | 101 | 164.93938(54)# | 10.3(16) s | β− | 165Tb | 1/2-# | ||
166Gd | 64 | 102 | 165.94160(64)# | 4.8(10) s | β− | 166Tb | 0+ | ||
167Gd | 64 | 103 | 166.94557(64)# | 3# s | β− | 167Tb | 5/2-# | ||
168Gd | 64 | 104 | 167.94836(75)# | 300# ms | β− | 168Tb | 0+ | ||
169Gd | 64 | 105 | 168.95287(86)# | 1# s | β− | 169Tb | 7/2-# |
- ^ Bold for isotopes with half-lives longer than the age of the universe (nearly stable)
- ^ Abbreviations:
EC: Electron capture
IT: Isomeric transition - ^ Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)
- ^ primordial radionuclide
- ^ Believed to undergo α decay to 150Sm
- ^ a b c d e f Fission product
- ^ Believed to undergo α decay to 151Sm
- ^ a b c Theoretically capable of spontaneous fission
- ^ Believed to undergo β−β− decay to 160Dy with a half-life over 1.3×1021 years
Notes
- Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
- Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
- Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.
References
- ^
F. A. Danevich; et al. (2001). "Quest for double beta decay of 160Gd and Ce isotopes". Nuclear Physics A. 694: 375. arXiv:nucl-ex/0011020. Bibcode:2001NuPhA.694..375D. doi:10.1016/S0375-9474(01)00983-6.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - ^ "Universal Nuclide Chart". Nucleonica. Retrieved 2012-05-30.
- Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
{{cite journal}}
: CS1 maint: multiple names: authors list (link)
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
- Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
{{cite journal}}
: Unknown parameter|laysummary=
ignored (help)
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
{{cite web}}
: Check date values in:|accessdate=
(help) - N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide (ed.). CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.
{{cite book}}
: Unknown parameter|nopp=
ignored (|no-pp=
suggested) (help)
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.