064 - Isotopes of Gadolinium - Wikipedia, The Free Encyclopedia

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Naturally occurring gadolinium (Gd) is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and 1radioisotope, 152Gd, with 158Gd being the most abundant (24.84% natural abundance). The predicted double beta decay of 160Gdhas 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-lifeof 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 than74.7 years. The majority of these have half-lives less than 24.6 seconds. Gadolinium isotopes have 10 metastable isomers, with themost stable being 143mGd (T½=110 seconds), 145mGd (T½=85 seconds) and 141mGd (T½=24.5 seconds).

The primary decay mode at atomic weights lower than the most abundant stable isotope, 158Gd, is electron capture, and the primarymode at higher atomic weights is beta decay. The primary decay products for isotopes of weights lower than 158Gd are the elementEu (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 agamma ray source in X-ray absorptiometry or bone density gauges for osteoporosis screening, and in the Lixiscope portable x-rayimaging system.Standard atomic mass: 157.25(3) u

Table

Isotopes of gadolinium - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Isotopes_of_gadolinium

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nuclidesymbol

Z(p) N(n)

isotopic mass (u) half-life[n 1] decay

mode(s)[2][n 2]daughter

isotope(s)[n 3]nuclear

spin

representativeisotopic

composition(mole fraction)

range of naturalvariation

(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) sβ+ 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) sβ+ 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) sβ+ (99.97%) 141Eu

(1/2+)β+, p (.03%) 140Sm

141mGd 377.8(2) keV 24.5(5) sβ+ (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) 142Sm144Gd 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) sIT (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) aα 144Sm

0+β+β+ (rare) 148Sm

149Gd 64 85 148.919341(4) 9.28(10) dβ+ 149Eu

7/2-α (4.34×10−4%) 145Sm

150Gd 64 86 149.918659(7) 1.79(8)×106 aα 146Sm

0+β+β+ (rare) 150Sm

151Gd 64 87 150.920348(4) 124(1) dEC 151Eu

7/2-α (10−6%) 147Sm


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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)1.^ Abbreviations:EC: Electron captureIT: Isomeric transition

2.

^ Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)3.^ primordial radionuclide4.^ Believed to undergo α decay to 150Sm5.^ a b c d e f Fission product6.^ Believed to undergo α decay to 151Sm7.^ a b c Theoretically capable of spontaneous fission8.^ Believed to undergo β-β- decay to 160Dy with a half-life over 1.3×1021 years9.

Notes

Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertaintyin 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 weakassignment arguments are enclosed in parentheses.Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote onestandard 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 (//arxiv.org/abs/nucl-ex/0011020). Bibcode:2001NuPhA.694..375D (http://adsabs.harvard.edu/abs/2001NuPhA.694..375D).doi:10.1016/S0375-9474(01)00983-6 (http://dx.doi.org/10.1016%2FS0375-9474%2801%2900983-6).

1.


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^ "Universal Nuclide Chart" (http://www.nucleonica.net/unc.aspx). Nucleonica. Retrieved 2012-05-30.2.

Isotope masses from:G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear anddecay properties" (http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf). Nuclear Physics A 729: 3–128.Bibcode:2003NuPhA.729....3A (http://adsabs.harvard.edu/abs/2003NuPhA.729....3A).doi:10.1016/j.nuclphysa.2003.11.001 (http://dx.doi.org/10.1016%2Fj.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). "Atomicweights of the elements. Review 2000 (IUPAC Technical Report)" (http://www.iupac.org/publications/pac/75/6/0683/pdf/). Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683 (http://dx.doi.org/10.1351%2Fpac200375060683).M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)" (http://iupac.org/publications/pac/78/11/2051/pdf/). Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051(http://dx.doi.org/10.1351%2Fpac200678112051). Lay summary (http://old.iupac.org/news/archives/2005/atomic-weights_revised05.html).

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 anddecay properties" (http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf). Nuclear Physics A 729: 3–128.Bibcode:2003NuPhA.729....3A (http://adsabs.harvard.edu/abs/2003NuPhA.729....3A).doi:10.1016/j.nuclphysa.2003.11.001 (http://dx.doi.org/10.1016%2Fj.nuclphysa.2003.11.001).National Nuclear Data Center. "NuDat 2.1 database" (http://www.nndc.bnl.gov/nudat2/). Brookhaven NationalLaboratory. Retrieved September 2005.N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRCPress. Section 11. ISBN 978-0-8493-0485-9.

Isotopes of europium Isotopes of gadolinium Isotopes of terbium

Table of nuclides

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