Isotopes of cadmium

Isotopes of cadmium (₄₈Cd)
IT	113Cd
Standard atomic weight Ar°(Cd)
	112.414±0.004; 112.41±0.01 (abridged);
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Naturally occurring cadmium (₄₈Cd) is composed of 8 isotopes. For two of them, natural radioactivity was observed, and three others are predicted to be radioactive but their decays have not been observed, due to extremely long half-lives. The two natural radioactive isotopes are ¹¹³Cd (beta decay, half-life is 8.04 × 10¹⁵ years) and ¹¹⁶Cd (two-neutrino double beta decay, half-life is 2.8 × 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. Three isotopes—¹¹⁰Cd, ¹¹¹Cd, and ¹¹²Cd—are theoretically stable. Among the isotopes absent in 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 12 known meta states, with the most stable being ^113mCd (t_1/2 14.1 years), ^115mCd (t_1/2 44.6 days) and ^117mCd (t_1/2 3.36 hours).

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).

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]

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}^{[n 7]}	Spin and parity ^{[n 8]}^{[n 9]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy^{[n 9]}			Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}^{[n 7]}	Spin and parity ^{[n 8]}^{[n 9]}	Normal proportion	Range of variation
⁹⁵Cd	48	47	94.94987(64)#	5# ms			9/2+#
⁹⁶Cd	48	48	95.93977(54)#	1# s	β⁺	⁹⁶Ag	0+
⁹⁷Cd	48	49	96.93494(43)#	2.8(6) s	β⁺ (>99.9%)	⁹⁷Ag	9/2+#
⁹⁷Cd	48	49	96.93494(43)#	2.8(6) s	β⁺, p (<.1%)	⁹⁶Pd	9/2+#
⁹⁸Cd	48	50	97.92740(8)	9.2(3) s	β⁺ (99.975%)	⁹⁸Ag	0+
⁹⁸Cd	48	50	97.92740(8)	9.2(3) s	β⁺, p (.025%)	⁹⁷Ag	0+
^98mCd	2427.5(6) keV			190(20) ns			8+#
⁹⁹Cd	48	51	98.92501(22)#	16(3) s	β⁺ (99.78%)	⁹⁹Ag	(5/2+)
					β⁺, p (.21%)	⁹⁸Pd
					β⁺, α (10⁻⁴%)	⁹⁵Rh
¹⁰⁰Cd	48	52	99.92029(10)	49.1(5) s	β⁺	¹⁰⁰Ag	0+
¹⁰¹Cd	48	53	100.91868(16)	1.36(5) min	β⁺	¹⁰¹Ag	(5/2+)
¹⁰²Cd	48	54	101.91446(3)	5.5(5) min	β⁺	¹⁰²Ag	0+
¹⁰³Cd	48	55	102.913419(17)	7.3(1) min	β⁺	¹⁰³Ag	5/2+
¹⁰⁴Cd	48	56	103.909849(10)	57.7(10) min	β⁺	¹⁰⁴Ag	0+
¹⁰⁵Cd	48	57	104.909468(12)	55.5(4) min	β⁺	¹⁰⁵Ag	5/2+
¹⁰⁶Cd	48	58	105.906459(6)	Observationally Stable^{[n 10]}			0+	0.0125(6)
¹⁰⁷Cd	48	59	106.906618(6)	6.50(2) h	β⁺	^107mAg	5/2+
¹⁰⁸Cd	48	60	107.904184(6)	Observationally Stable^{[n 11]}			0+	0.0089(3)
¹⁰⁹Cd	48	61	108.904982(4)	461.4(12) d	EC	¹⁰⁹Ag	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^{[n 12]}	48	63	110.9041781(29)	Stable			1/2+	0.1280(12)
^111mCd	396.214(21) keV			48.50(9) min	IT	¹¹¹Cd	11/2−
¹¹²Cd^{[n 12]}	48	64	111.9027578(29)	Stable			0+	0.2413(21)
¹¹³Cd^{[n 12]}^{[n 13]}	48	65	112.9044017(29)	8.04(5)×10¹⁵ y	β⁻	¹¹³In	1/2+	0.1222(12)
^113mCd^{[n 12]}	263.54(3) keV			14.1(5) y	β⁻ (99.86%)	¹¹³In	11/2−
^113mCd^{[n 12]}	263.54(3) keV			14.1(5) y	IT (.139%)	¹¹³Cd	11/2−
¹¹⁴Cd^{[n 12]}	48	66	113.9033585(29)	Observationally Stable^{[n 14]}			0+	0.2873(42)
¹¹⁵Cd^{[n 12]}	48	67	114.9054310(29)	53.46(5) h	β⁻	^115mIn	1/2+
^115mCd	181.0(5) keV			44.56(24) d	β⁻	^115mIn	(11/2)−
¹¹⁶Cd^{[n 12]}^{[n 13]}	48	68	115.904756(3)	2.8(2)×10¹⁹ y	β⁻β⁻	¹¹⁶Sn	0+	0.0749(18)
¹¹⁷Cd	48	69	116.907219(4)	2.49(4) h	β⁻	^117mIn	1/2+
^117mCd	136.4(2) keV			3.36(5) h	β⁻	^117mIn	(11/2)−
¹¹⁸Cd	48	70	117.906915(22)	50.3(2) min	β⁻	¹¹⁸In	0+
¹¹⁹Cd	48	71	118.90992(9)	2.69(2) min	β⁻	^119mIn	(3/2+)
^119mCd	146.54(11) keV			2.20(2) min	β⁻	^119mIn	(11/2−)#
¹²⁰Cd	48	72	119.90985(2)	50.80(21) s	β⁻	¹²⁰In	0+
¹²¹Cd	48	73	120.91298(9)	13.5(3) s	β⁻	^121mIn	(3/2+)
^121mCd	214.86(15) keV			8.3(8) s	β⁻	^121mIn	(11/2−)
¹²²Cd	48	74	121.91333(5)	5.24(3) s	β⁻	¹²²In	0+
¹²³Cd	48	75	122.91700(4)	2.10(2) s	β⁻	^123mIn	(3/2)+
^123mCd	316.52(23) keV			1.82(3) s	β⁻	¹²³In	(11/2−)
^123mCd	316.52(23) keV			1.82(3) s	IT	¹²³Cd	(11/2−)
¹²⁴Cd	48	76	123.91765(7)	1.25(2) s	β⁻	¹²⁴In	0+
¹²⁵Cd	48	77	124.92125(7)	0.65(2) s	β⁻	^125mIn	(3/2+)#
^125mCd	50(70) keV			570(90) ms	β⁻	¹²⁵In	11/2−#
¹²⁶Cd	48	78	125.92235(6)	0.515(17) s	β⁻	¹²⁶In	0+
¹²⁷Cd	48	79	126.92644(8)	0.37(7) s	β⁻	^127mIn	(3/2+)
¹²⁸Cd	48	80	127.92776(32)	0.28(4) s	β⁻	¹²⁸In	0+
¹²⁹Cd	48	81	128.93215(32)#	242(8) ms	β⁻ (>99.9%)	¹²⁹In	3/2+#
¹²⁹Cd	48	81	128.93215(32)#	242(8) ms	IT (<.1%)	¹²⁹Cd	3/2+#
^129mCd	0(200)# keV			104(6) ms			11/2−#
¹³⁰Cd	48	82	129.9339(3)	162(7) ms	β⁻ (96%)	¹³⁰In	0+
¹³⁰Cd	48	82	129.9339(3)	162(7) ms	β⁻, n (4%)	¹²⁹In	0+
¹³¹Cd	48	83	130.94067(32)#	68(3) ms			7/2−#
¹³²Cd	48	84	131.94555(54)#	97(10) ms			0+
This table header & footer: view

Hyperdeformation is predicted to be found in ¹⁰⁷Cd.

Cadmium-113m

Medium-lived
fission products ^{[further explanation needed]}
	t_½ (year)	Yield (%)	Q (keV)	βγ
¹⁵⁵Eu	4.76	0.0803	252	βγ
⁸⁵Kr	10.76	0.2180	687	βγ
^113mCd	14.1	0.0008	316	β
⁹⁰Sr	28.9	4.505	2826	β
¹³⁷Cs	30.23	6.337	1176	βγ
^121mSn	43.9	0.00005	390	βγ
¹⁵¹Sm	88.8	0.5314	77	β

Cadmium-113m is a cadmium radioisotope and nuclear isomer with a half-life of 14.1 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.

References

Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

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