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Isotopes of caesium



Caesium (Cs) has at least 39 known isotopes, which is more than any other element except francium. The atomic masses of these isotopes range from 112 to 151. Even though this element has a large number of isotopes, it has only one naturally occurring stable isotope, 133Cs. Most of the other isotopes have half-lives from a few days to fractions of a second. The radiogenic isotope 137Cs has been used in hydrologic studies, analogous to the use of 3H. 137Cs is produced from the detonation of nuclear weapons and is produced in nuclear power plants, and was released to the atmosphere most notably from the 1986 Chernobyl meltdown. It's because this isotope (137Cs) is one of the numerous products of fission, directly issue from the fission of a uranium core.

Additional recommended knowledge

Beginning in 1945 with the commencement of nuclear testing, 137Cs was released into the atmosphere where it is absorbed readily into solution and is returned to the surface of the earth as a component of radioactive fallout. Once 137Cs enters the ground water, it is deposited on soil surfaces and removed from the landscape primarily by particle transport. As a result, the input function of these isotopes can be estimated as a function of time. Caesium-137 has a half-life of 30.17 years. It decomposes to barium-137m (a short-lived product of decay) then to a form of nonradioactive barium.


Standard atomic mass: 132.9054519(2) 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
112Cs 55 57 111.95030(33)# 500(100) µs 1+#
113Cs 55 58 112.94449(11) 16.7(7) µs 5/2+#
114Cs 55 59 113.94145(33)# 0.57(2) s (1+)
115Cs 55 60 114.93591(32)# 1.4(8) s 9/2+#
116Cs 55 61 115.93337(11)# 0.70(4) s (1+)
116mCs 100(60)# keV 3.85(13) s 4+,5,6
117Cs 55 62 116.92867(7) 8.4(6) s (9/2+)#
117mCs 150(80)# keV 6.5(4) s 3/2+#
118Cs 55 63 117.926559(14) 14(2) s 2
118mCs 100(60)# keV 17(3) s (7-)
119Cs 55 64 118.922377(15) 43.0(2) s 9/2+
119mCs 50(30)# keV 30.4(1) s 3/2(+)
120Cs 55 65 119.920677(11) 61.2(18) s 2(-#)
120mCs 100(60)# keV 57(6) s (7-)
121Cs 55 66 120.917229(15) 155(4) s 3/2(+)
121mCs 68.5(3) keV 122(3) s 9/2(+)
122Cs 55 67 121.91611(3) 21.18(19) s 1+
122m1Cs 45.8 keV >1 µs (3)+
122m2Cs 140(30) keV 3.70(11) min 8-
122m3Cs 127.0(5) keV 360(20) ms (5)-
123Cs 55 68 122.912996(13) 5.88(3) min 1/2+
123m1Cs 156.27(5) keV 1.64(12) s (11/2)-
123m2Cs 231.63+X keV 114(5) ns (9/2+)
124Cs 55 69 123.912258(9) 30.9(4) s 1+
124mCs 462.55(17) keV 6.3(2) s (7)+
125Cs 55 70 124.909728(8) 46.7(1) min 1/2(+)
125mCs 266.6(11) keV 900(30) ms (11/2-)
126Cs 55 71 125.909452(13) 1.64(2) min 1+
126m1Cs 273.0(7) keV >1 µs
126m2Cs 596.1(11) keV 171(14) µs
127Cs 55 72 126.907418(6) 6.25(10) h 1/2+
127mCs 452.23(21) keV 55(3) µs (11/2)-
128Cs 55 73 127.907749(6) 3.640(14) min 1+
129Cs 55 74 128.906064(5) 32.06(6) h 1/2+
130Cs 55 75 129.906709(9) 29.21(4) min 1+
130mCs 163.25(11) keV 3.46(6) min 5-
131Cs 55 76 130.905464(5) 9.689(16) d 5/2+
132Cs 55 77 131.9064343(20) 6.480(6) d 2+
133Cs 55 78 132.905451933(24) STABLE 7/2+ 1.0000
134Cs 55 79 133.906718475(28) 2.0652(4) a 4+
134mCs 138.7441(26) keV 2.912(2) h 8-
135Cs 55 80 134.9059770(11) 2.3(3)E+6 a 7/2+
135mCs 1632.9(15) keV 53(2) min 19/2-
136Cs 55 81 135.9073116(20) 13.16(3) d 5+
136mCs 518(5) keV 19(2) s 8-
137Cs 55 82 136.9070895(5) 30.1671(13) a 7/2+
138Cs 55 83 137.911017(10) 33.41(18) min 3-
138mCs 79.9(3) keV 2.91(8) min 6-
139Cs 55 84 138.913364(3) 9.27(5) min 7/2+
140Cs 55 85 139.917282(9) 63.7(3) s 1-
141Cs 55 86 140.920046(11) 24.84(16) s 7/2+
142Cs 55 87 141.924299(11) 1.689(11) s 0-
143Cs 55 88 142.927352(25) 1.791(7) s 3/2+
144Cs 55 89 143.932077(28) 994(4) ms 1(-#)
144mCs 300(200)# keV <1 s (>3)
145Cs 55 90 144.935526(12) 582(6) ms 3/2+
146Cs 55 91 145.94029(8) 0.321(2) s 1-
147Cs 55 92 146.94416(6) 0.235(3) s (3/2+)
148Cs 55 93 147.94922(62) 146(6) ms
149Cs 55 94 148.95293(21)# 150# ms [>50 ms] 3/2+#
150Cs 55 95 149.95817(32)# 100# ms [>50 ms]
151Cs 55 96 150.96219(54)# 60# ms [>50 ms] 3/2+#

Notes

  • 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

  • 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 xenon Isotopes of caesium Isotopes of barium
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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isotopes_of_caesium". A list of authors is available in Wikipedia.
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