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Isotopes of cadmium



Naturally occurring Cadmium (Cd) is composed of 8 isotopes. For two of them, natural radioactivity was observed, and three others are predicted to be radioactive but their decays were never observed, due to extremely long half-life times. The two natural radioactive isotopes are 113Cd (beta decay, half-life is 7.7 × 1015 years) and 116Cd (two-neutrino double beta decay, half-life is 2.9 × 1019 years). The other three are 106Cd, 108Cd (double electron capture), and 114Cd (double beta decay); only lower limits on their half-life times have been set. At least three isotopes - 110Cd, 111Cd, and 112Cd - are absolutely stable. Among the isotopes absent in the natural cadmium, the most long-lived are 109Cd with a half-life of 462.6 days, and 115Cd with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lives that are less than 2.5 hours and the majority of these have half-lives that are less than 5 minutes. This element also has 8 known meta states with the most stable being 113mCd (t½ 14.1 years), 115mCd (t½ 44.6 days) and 117mCd (t½ 3.36 hours).

Additional recommended knowledge

The known isotopes of cadmium range in atomic mass from 94.950 u (95Cd) to 131.946 u (132Cd). The primary decay mode before the second most abundant stable isotope, 112Cd, is electron capture and the primary modes after are beta emission and electron capture. The primary decay product before 112Cd is element 47 (silver) and the primary product after is element 49 (indium).
Standard atomic mass: 112.411(8) 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
95Cd 48 47 94.94987(64)# 5# ms 9/2+#
96Cd 48 48 95.93977(54)# 1# s 0+
97Cd 48 49 96.93494(43)# 2.8(6) s 9/2+#
98Cd 48 50 97.92740(8) 9.2(3) s 0+
98mCd 2427.5(6) keV 190(20) ns 8+#
99Cd 48 51 98.92501(22)# 16(3) s (5/2+)
100Cd 48 52 99.92029(10) 49.1(5) s 0+
101Cd 48 53 100.91868(16) 1.36(5) min (5/2+)
102Cd 48 54 101.91446(3) 5.5(5) min 0+
103Cd 48 55 102.913419(17) 7.3(1) min 5/2+
104Cd 48 56 103.909849(10) 57.7(10) min 0+
105Cd 48 57 104.909468(12) 55.5(4) min 5/2+
106Cd 48 58 105.906459(6) STABLE [>410E+18 a] 0+ 0.0125(6)
107Cd 48 59 106.906618(6) 6.50(2) h 5/2+
108Cd 48 60 107.904184(6) STABLE [>410E+15 a] 0+ 0.0089(3)
109Cd 48 61 108.904982(4) 461.4(12) d 5/2+
109m1Cd 59.6(4) keV 12(2) µs 1/2+
109m2Cd 463.0(5) keV 10.9(5) µs 11/2-
110Cd 48 62 109.9030021(29) STABLE 0+ 0.1249(18)
111Cd 48 63 110.9041781(29) STABLE 1/2+ 0.1280(12)
111mCd 396.214(21) keV 48.50(9) min 11/2-
112Cd 48 64 111.9027578(29) STABLE 0+ 0.2413(21)
113Cd 48 65 112.9044017(29) 7.7(3)E+15 a 1/2+ 0.1222(12)
113mCd 263.54(3) keV 14.1(5) a 11/2-
114Cd 48 66 113.9033585(29) STABLE [>6.4E+18 a] 0+ 0.2873(42)
115Cd 48 67 114.9054310(29) 53.46(5) h 1/2+
115mCd 181.0(5) keV 44.56(24) d (11/2)-
116Cd 48 68 115.904756(3) 3.1(4)E+19 a 0+ 0.0749(18)
117Cd 48 69 116.907219(4) 2.49(4) h 1/2+
117mCd 136.4(2) keV 3.36(5) h (11/2)-
118Cd 48 70 117.906915(22) 50.3(2) min 0+
119Cd 48 71 118.90992(9) 2.69(2) min (3/2+)
119mCd 146.54(11) keV 2.20(2) min (11/2-)#
120Cd 48 72 119.90985(2) 50.80(21) s 0+
121Cd 48 73 120.91298(9) 13.5(3) s (3/2+)
121mCd 214.86(15) keV 8.3(8) s (11/2-)
122Cd 48 74 121.91333(5) 5.24(3) s 0+
123Cd 48 75 122.91700(4) 2.10(2) s (3/2)+
123mCd 316.52(23) keV 1.82(3) s (11/2-)
124Cd 48 76 123.91765(7) 1.25(2) s 0+
125Cd 48 77 124.92125(7) 0.65(2) s (3/2+)#
125mCd 50(70) keV 570(90) ms 11/2-#
126Cd 48 78 125.92235(6) 0.515(17) s 0+
127Cd 48 79 126.92644(8) 0.37(7) s (3/2+)
128Cd 48 80 127.92776(32) 0.28(4) s 0+
129Cd 48 81 128.93215(32)# 242(8) ms 3/2+#
129mCd 0(200)# keV 104(6) ms 11/2-#
130Cd 48 82 129.9339(3) 162(7) ms 0+
131Cd 48 83 130.94067(32)# 68(3) ms 7/2-#
132Cd 48 84 131.94555(54)# 97(10) ms 0+

Notes

  • The precision of the isotope abundances and atomic mass is limited through variations. The given ranges should be applicable to any normal terrestrial material.
  • 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

  • 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 silver Isotopes of cadmium Isotopes of indium
Index to isotope pages
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isotopes_of_cadmium". A list of authors is available in Wikipedia.
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