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Standard atomic weight Ar°(Cd) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Naturally occurring cadmium (48Cd) is composed of 8 isotopes. For two of them, natural radioactivity has been observed, and three others are predicted to possibly decay though this has not been observed; it may be presumed the half-lives are extremely long. The two natural radioactive isotopes are 113Cd (beta decay, half-life 8.04×1015 years) and 116Cd (double beta decay, half-life 2.69×1019 years). The other three are 106Cd, 108Cd (double electron capture), and 114Cd (double beta decay); only lower limits on their decays have been set. Only three isotopes—110-112Cd—are theoretically stable. Among the isotopes absent in natural cadmium, the most long-lived are 109Cd with a half-life of 461.3 days, and 115Cd with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lives that are less than 7 hours and the majority of these are less than 5 minutes. This element also has 12 known meta states, with the most stable being 113mCd (t1/2 13.9 years), 115mCd (t1/2 44.6 days) and 117mCd (t1/2 3.44 hours).
The known isotopes of cadmium range from 95Cd to 132Cd. The primary decay mode before the stable isotope 112Cd is electron capture to isotopes of silver, and after, beta emission to isotopes of indium.
A 2021 study has shown at high ionic strengths, Cd isotope fractionation mainly depends on its complexation with carboxylic sites. At low ionic strengths, nonspecific Cd binding induced by electrostatic attractions plays a dominant role and promotes Cd isotope fractionation during complexation. [4]
Nuclide [n 1] | Z | N | Isotopic mass (Da) [5] [n 2] [n 3] | Half-life [1] [n 4] | Decay mode [1] [n 5] | Daughter isotope [n 6] [n 7] | Spin and parity [1] [n 8] [n 9] | Natural abundance (mole fraction) | |||||||||||
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Excitation energy [n 9] | Normal proportion [1] | Range of variation | |||||||||||||||||
94Cd | 48 | 46 | 93.95659(54)# | 80# ms [> 760 ns] | 0+ | ||||||||||||||
95Cd | 48 | 47 | 94.94948(61)# | 32(3) ms | β+ (95.4%) | 95Ag | 9/2+# | ||||||||||||
β+, p (4.6%) | 94Pd | ||||||||||||||||||
96Cd | 48 | 48 | 95.94034(44)# | 1.003(47) s | β+ (98.4%) | 96Ag | 0+ | ||||||||||||
β+, p (1.6%) | 95Pd | ||||||||||||||||||
96m1Cd | 6000(1400) keV | 511(26) ms | β+ (84.6%) | 96Ag | 16+ | ||||||||||||||
β+, p (15.4%) | 95Pd | ||||||||||||||||||
96m2Cd | 5605(5) keV | 198(18) ns | IT | 96Cd | (12−,13−) | ||||||||||||||
97Cd | 48 | 49 | 96.93480(45) | 1.16(5) s | β+ (92.6%) | 97Ag | (9/2+) | ||||||||||||
β+, p (7.4%) | 96Pd | ||||||||||||||||||
97m1Cd | 1245.1(2) keV | 730(70) μs | IT | 97Cd | (1/2−) | ||||||||||||||
97m2Cd | 2620(580) keV | 3.86(6) s | β+ (74.9%) | 97Ag | (25/2+) | ||||||||||||||
β+, p (25.1%) | 96Pd | ||||||||||||||||||
98Cd | 48 | 50 | 97.927389(56) | 9.29(10) s | β+ (>99.97%) | 98Ag | 0+ | ||||||||||||
β+, p (<0.029%) | 97Pd | ||||||||||||||||||
98m1Cd | 2428.3(4) keV | 154(16) ns | IT | 98Cd | (8+) | ||||||||||||||
98m2Cd | 6635(2) keV | 224(5) ns | IT | 98Cd | (12+) | ||||||||||||||
99Cd | 48 | 51 | 98.9249258(17) | 17(1) s | β+ (99.79%) | 99Ag | 5/2+# | ||||||||||||
β+, p (0.21%) | 98Pd | ||||||||||||||||||
β+, α (<10−4%) | 95Rh | ||||||||||||||||||
100Cd | 48 | 52 | 99.9203488(18) | 49.1(5) s | β+ | 100Ag | 0+ | ||||||||||||
101Cd | 48 | 53 | 100.9185862(16) | 1.36(5) min | β+ | 101Ag | 5/2+ | ||||||||||||
102Cd | 48 | 54 | 101.9144818(18) | 5.5(5) min | β+ | 102Ag | 0+ | ||||||||||||
103Cd | 48 | 55 | 102.9134169(19) | 7.3(1) min | β+ | 103Ag | 5/2+ | ||||||||||||
104Cd | 48 | 56 | 103.9098562(18) | 57.7(10) min | β+ | 104Ag | 0+ | ||||||||||||
105Cd | 48 | 57 | 104.9094639(15) | 55.5(4) min | β+ | 105Ag | 5/2+ | ||||||||||||
105mCd | 2517.6(5) keV | 4.5(5) μs | IT | 105Cd | (21/2+) | ||||||||||||||
106Cd | 48 | 58 | 105.9064598(12) | Observationally stable [n 10] | 0+ | 0.01245(22) | |||||||||||||
107Cd | 48 | 59 | 106.9066120(18) | 6.50(2) h | β+ | 107Ag | 5/2+ | ||||||||||||
108Cd | 48 | 60 | 107.9041836(12) | Observationally stable [n 11] | 0+ | 0.00888(11) | |||||||||||||
109Cd | 48 | 61 | 108.9049867(16) | 461.3(5) d | EC | 109Ag | 5/2+ | ||||||||||||
109m1Cd | 59.60(7) keV | 11.8(16) μs | IT | 109Cd | 1/2+ | ||||||||||||||
109m2Cd | 463.10(11) keV | 10.6(4) μs | IT | 109Cd | 11/2− | ||||||||||||||
110Cd | 48 | 62 | 109.90300747(41) | Stable | 0+ | 0.12470(61) | |||||||||||||
111Cd [n 12] | 48 | 63 | 110.90418378(38) | Stable | 1/2+ | 0.12795(12) | |||||||||||||
111mCd | 396.214(21) keV | 48.50(9) min | IT | 111Cd | 11/2− | ||||||||||||||
112Cd [n 12] | 48 | 64 | 111.90276390(27) | Stable | 0+ | 0.24109(7) | |||||||||||||
113Cd [n 12] [n 13] | 48 | 65 | 112.90440811(26) | 8.04(5)×1015 y | β− | 113In | 1/2+ | 0.12227(7) | |||||||||||
113mCd [n 12] | 263.54(3) keV | 13.89(11) y | β− (99.90%) | 113In | 11/2− | ||||||||||||||
IT (0.0964%) | 113Cd | ||||||||||||||||||
114Cd [n 12] | 48 | 66 | 113.90336500(30) | Observationally stable [n 14] | 0+ | 0.28754(81) | |||||||||||||
115Cd [n 12] | 48 | 67 | 114.90543743(70) | 53.46(5) h | β− | 115mIn | 1/2+ | ||||||||||||
115mCd [n 12] | 181.0(5) keV | 44.56(24) d | β− | 115In | 11/2− | ||||||||||||||
116Cd [n 12] [n 13] | 48 | 68 | 115.90476323(17) | 2.69(9)×1019 y | β−β− | 116Sn | 0+ | 0.07512(54) | |||||||||||
117Cd | 48 | 69 | 116.9072260(11) | 2.503(5) h | β− | 117In | 1/2+ | ||||||||||||
117mCd | 136.4(2) keV | 3.441(9) h | β− | 117In | 11/2− | ||||||||||||||
118Cd | 48 | 70 | 117.906922(21) | 50.3(2) min | β− | 118In | 0+ | ||||||||||||
119Cd | 48 | 71 | 118.909847(40) | 2.69(2) min | β− | 119In | 1/2+ | ||||||||||||
119mCd | 146.54(11) keV | 2.20(2) min | β− | 119In | 11/2− | ||||||||||||||
120Cd | 48 | 72 | 119.9098681(40) | 50.80(21) s | β− | 120In | 0+ | ||||||||||||
121Cd | 48 | 73 | 120.9129637(21) | 13.5(3) s | β− | 121In | 3/2+ | ||||||||||||
121mCd | 214.86(15) keV | 8.3(8) s | β− | 121In | 11/2− | ||||||||||||||
122Cd | 48 | 74 | 121.9134591(25) | 5.98(10) s [6] | β− | 122In | 0+ | ||||||||||||
123Cd | 48 | 75 | 122.9168925(29) | 2.10(2) s | β− | 123In | 3/2+ | ||||||||||||
123mCd | 143(4) keV | 1.82(3) s | β− (?%) | 123In | 11/2− | ||||||||||||||
IT (?%) | 123Cd | ||||||||||||||||||
124Cd | 48 | 76 | 123.9176598(28) | 1.25(2) s | β− | 124In | 0+ | ||||||||||||
125Cd | 48 | 77 | 124.9212576(31) | 680(40) ms | β− | 125In | 3/2+ | ||||||||||||
125m1Cd | 186(4) keV | 480(30) ms | β− | 125In | 11/2− | ||||||||||||||
125m2Cd | 1648(4) keV | 19(3) μs | IT | 125Cd | (19/2+) | ||||||||||||||
126Cd | 48 | 78 | 125.9224303(25) | 512(5) ms | β− | 126In | 0+ | ||||||||||||
127Cd | 48 | 79 | 126.9262033(67) | 480(100) ms | β− | 127In | 3/2+ | ||||||||||||
127m1Cd | 285(8) keV | 360(40) ms | β− | 127In | 11/2− | ||||||||||||||
127m2Cd | 1845(8) keV | 17.5(3) μs | IT | 127Cd | (19/2+) | ||||||||||||||
128Cd | 48 | 80 | 127.9278168(69) | 246(2) ms | β− | 128In | 0+ | ||||||||||||
128m1Cd | 1870.5(3) keV | 270(7) ns | IT | 128Cd | (5−) | ||||||||||||||
128m2Cd | 2714.6(4) keV | 3.56(6) μs | IT | 128Cd | (10+) | ||||||||||||||
128m2Cd | 4286.6(15) keV | 6.3(8) ms | IT | 128Cd | (15−) | ||||||||||||||
129Cd | 48 | 81 | 128.9322356(57) | 147(3) ms | β− (?%) | 129In | 11/2− | ||||||||||||
β−, n (?%) | 128In | ||||||||||||||||||
129m1Cd | 343(8) keV | 157(8) ms | β− (?%) | 129In | 3/2+ | ||||||||||||||
β−, n (?%) | 128In | ||||||||||||||||||
129m2Cd | 2283(8) keV | 3.6(2) ms | IT | 129Cd | (21/2+) | ||||||||||||||
130Cd | 48 | 82 | 129.934388(24) | 126.8(18) ms | β− (96.5%) | 130In | 0+ | ||||||||||||
β−, n (3.5%) | 129In | ||||||||||||||||||
130mCd | 2129.6(10) keV | 240(16) ns | IT | 130Cd | (8+) | ||||||||||||||
131Cd | 48 | 83 | 130.940728(21) | 98(2) ms | β− (96.5%) | 131In | 7/2−# | ||||||||||||
β−, n (3.5%) | 130In | ||||||||||||||||||
132Cd | 48 | 84 | 131.945823(64) | 84(5) ms | β−, n (60%) | 131In | 0+ | ||||||||||||
β− (40%) | 132In | ||||||||||||||||||
133Cd | 48 | 85 | 132.95261(22)# | 61(6) ms | β− (?%) | 133In | 7/2−# | ||||||||||||
β−, n (?%) | 132In | ||||||||||||||||||
134Cd | 48 | 86 | 133.95764(32)# | 65(15) ms | β− | 134In | 0+ | ||||||||||||
This table header & footer: |
EC: | Electron capture |
IT: | Isomeric transition |
n: | Neutron emission |
p: | Proton emission |
Nuclide | t1⁄2 | Yield | Q [a 1] | βγ |
---|---|---|---|---|
(a) | (%) [a 2] | (keV) | ||
155Eu | 4.74 | 0.0803 [a 3] | 252 | βγ |
85Kr | 10.73 | 0.2180 [a 4] | 687 | βγ |
113mCd | 13.9 | 0.0008 [a 3] | 316 | β |
90Sr | 28.91 | 4.505 | 2826 [a 5] | β |
137Cs | 30.04 | 6.337 | 1176 | βγ |
121mSn | 43.9 | 0.00005 | 390 | βγ |
151Sm | 94.6 | 0.5314 [a 3] | 77 | β |
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Cadmium-113m is a cadmium radioisotope and nuclear isomer with a half-life of 13.9 years. In a normal thermal reactor, it has a very low fission product yield, plus its large neutron capture cross section means that most of even the small amount produced is destroyed in the course of the nuclear fuel's burnup; thus, this isotope is not a significant contributor to nuclear waste.
Fast fission or fission of some heavier actinides [ which? ] will produce 113mCd at higher yields.
Daughter products other than cadmium