My watch list
my.chemeurope.com  
Login  

Isotopes of xenon



Naturally occurring xenon (Xe) is made of nine stable isotopes. (124Xe, 134Xe and 136Xe are predicted to undergo double beta decay, but this has never been observed, so they are considered to be stable.)[1][2] Xenon, with mercury, has the second highest number of stable isotopes. Only tin, with 10 stable isotopes, has more.[3] Beyond these stable forms, there are over 40 unstable isotopes that have been studied. 129Xe is produced by beta decay of 129I (half-life: 16 million years); 131mXe, 133Xe, 133mXe, and 135Xe are some of the fission products of both 235U and 239Pu, and therefore used as indicators of nuclear explosions.

Additional recommended knowledge

The artificial isotope 135Xe is of considerable significance in the operation of nuclear fission reactors. 135Xe has a huge cross section for thermal neutrons, 2.65x106 barns, so it acts as a neutron absorber or "poison" that can slow or stop the chain reaction after a period of operation. This was discovered in the earliest nuclear reactors built by the American Manhattan Project for plutonium production. Fortunately the designers had made provisions in the design to increase the reactor's reactivity (the number of neutrons per fission that go on to fission other atoms of nuclear fuel).

Relatively high concentrations of radioactive xenon isotopes are also found emanating from nuclear reactors due to the release of this fission gas from cracked fuel rods or fissioning of uranium in cooling water. The concentrations of these isotopes are still usually low compared to naturally occurring radioactive noble gases such as 222Rn.

Because xenon is a tracer for two parent isotopes, Xe isotope ratios in meteorites are a powerful tool for studying the formation of the solar system. The I-Xe method of dating gives the time elapsed between nucleosynthesis and the condensation of a solid object from the solar nebula. Xenon isotopes are also a powerful tool for understanding terrestrial differentiation. Excess 129Xe found in carbon dioxide well gases from New Mexico was believed to be from the decay of mantle-derived gases soon after Earth's formation.[4]
Standard atomic mass: 131.293(6) u

Table

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life nuclear
spin
representative
isotopic
composition
(mole fraction)
range of natural
variation
(mole fraction)
excitation energy
110Xe 54 56 109.94428(14) 310(190) ms [105(+35-25) ms] 0+
111Xe 54 57 110.94160(33)# 740(200) ms 5/2+#
112Xe 54 58 111.93562(11) 2.7(8) s 0+
113Xe 54 59 112.93334(9) 2.74(8) s (5/2+)#
114Xe 54 60 113.927980(12) 10.0(4) s 0+
115Xe 54 61 114.926294(13) 18(4) s (5/2+)
116Xe 54 62 115.921581(14) 59(2) s 0+
117Xe 54 63 116.920359(11) 61(2) s 5/2(+)
118Xe 54 64 117.916179(11) 3.8(9) min 0+
119Xe 54 65 118.915411(11) 5.8(3) min 5/2(+)
120Xe 54 66 119.911784(13) 40(1) min 0+
121Xe 54 67 120.911462(12) 40.1(20) min (5/2+)
122Xe 54 68 121.908368(12) 20.1(1) h 0+
123Xe 54 69 122.908482(10) 2.08(2) h 1/2+
123mXe 185.18(22) keV 5.49(26) µs 7/2(-)
124Xe 54 70 123.905893(2) STABLE [>48E+15 a] 0+ 0.000952(3)
125Xe 54 71 124.9063955(20) 16.9(2) h 1/2(+)
125m1Xe 252.60(14) keV 56.9(9) s 9/2(-)
125m2Xe 295.86(15) keV 0.14(3) µs 7/2(+)
126Xe 54 72 125.904274(7) STABLE 0+ 0.000890(2)
127Xe 54 73 126.905184(4) 36.345(3) d 1/2+
127mXe 297.10(8) keV 69.2(9) s 9/2-
128Xe 54 74 127.9035313(15) STABLE 0+ 0.019102(8)
129Xe 54 75 128.9047794(8) STABLE 1/2+ 0.264006(82)
129mXe 236.14(3) keV 8.88(2) d 11/2-
130Xe 54 76 129.9035080(8) STABLE 0+ 0.040710(13)
131Xe 54 77 130.9050824(10) STABLE 3/2+ 0.212324(30)
131mXe 163.930(8) keV 11.934(21) d 11/2-
132Xe 54 78 131.9041535(10) STABLE 0+ 0.269086(33)
132mXe 2752.27(17) keV 8.39(11) ms (10+)
133Xe 54 79 132.9059107(26) 5.2475(5) d 3/2+
133mXe 233.221(18) keV 2.19(1) d 11/2-
134Xe 54 80 133.9053945(9) STABLE [>11E+15 a] 0+ 0.104357(21)
134m1Xe 1965.5(5) keV 290(17) ms 7-
134m2Xe 3025.2(15) keV 5(1) µs (10+)
135Xe 54 81 134.907227(5) 9.14(2) h 3/2+
135mXe 526.551(13) keV 15.29(5) min 11/2-
136Xe 54 82 135.907219(8) STABLE [>10E+21 a] 0+ 0.088573(44)
136mXe 1891.703(14) keV 2.95(9) µs 6+
137Xe 54 83 136.911562(8) 3.818(13) min 7/2-
138Xe 54 84 137.91395(5) 14.08(8) min 0+
139Xe 54 85 138.918793(22) 39.68(14) s 3/2-
140Xe 54 86 139.92164(7) 13.60(10) s 0+
141Xe 54 87 140.92665(10) 1.73(1) s 5/2(-#)
142Xe 54 88 141.92971(11) 1.22(2) s 0+
143Xe 54 89 142.93511(21)# 0.511(6) s 5/2-
144Xe 54 90 143.93851(32)# 0.388(7) s 0+
145Xe 54 91 144.94407(32)# 188(4) ms (3/2-)#
146Xe 54 92 145.94775(43)# 146(6) ms 0+
147Xe 54 93 146.95356(43)# 130(80) ms [0.10(+10-5) s] 3/2-#

Notes

  • The isotopic composition refers to that in air.
  • 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.
  • Commercially available materials may have been subjected to an undisclosed or inadvertent isotopic fractionation. Substantial deviations from the given mass and composition can occur.
  • 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

  1. ^ Status of ßß-decay in Xenon, Roland Lüscher, accessed on line September 17, 2007.
  2. ^ Average (Recommended) Half-Life Values for Two-Neutrino Double-Beta Decay, A. S. Barabash, Czechoslovak Journal of Physics 52, #4 (April 2002), pp. 567–573.
  3. ^ Rajam, J. B. (1960). Atomic Physics, 7th edition, Delhi: S. Chand and Co.. ISBN 812191809X. 
  4. ^ Boulos, M.S.; Manuel, O.K. (1971). "The xenon record of extinct radioactivities in the Earth.". Science 174: 1334-1336.
  • Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
  • Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
  • Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
    • Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
    • National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
    • David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.


Isotopes of iodine Isotopes of xenon Isotopes of caesium
Index to isotope pages
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isotopes_of_xenon". A list of authors is available in Wikipedia.
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE