Isotopes of palladium

Isotopes of palladium (₄₆Pd)
γ	–
Standard atomic weight Ar°(Pd)
	106.42±0.01; 106.42±0.01 (abridged);
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Natural palladium (₄₆Pd) is composed of six stable isotopes, ¹⁰²Pd, ¹⁰⁴Pd, ¹⁰⁵Pd, ¹⁰⁶Pd, ¹⁰⁸Pd, and ¹¹⁰Pd, although ¹⁰²Pd and ¹¹⁰Pd are theoretically unstable. The most stable radioisotopes are ¹⁰⁷Pd with a half-life of 6.5 million years, ¹⁰³Pd with a half-life of 17 days, and ¹⁰⁰Pd with a half-life of 3.63 days. Twenty-three other radioisotopes have been characterized with atomic weights ranging from 90.949 u (⁹¹Pd) to 128.96 u (¹²⁹Pd). Most of these have half-lives that are less than a half an hour except ¹⁰¹Pd (half-life: 8.47 hours), ¹⁰⁹Pd (half-life: 13.7 hours), and ¹¹²Pd (half-life: 21 hours).

The primary decay mode before the most abundant stable isotope, ¹⁰⁶Pd, is electron capture and the primary mode after is beta decay. The primary decay product before ¹⁰⁶Pd is rhodium and the primary product after is silver.

Radiogenic ¹⁰⁷Ag is a decay product of ¹⁰⁷Pd and was first discovered in the Santa Clara meteorite of 1978.^[4] The discoverers suggest that the coalescence and differentiation of iron-cored small planets may have occurred 10 million years after a nucleosynthetic event. ¹⁰⁷Pd versus Ag correlations observed in bodies, which have clearly been melted since accretion of the Solar System, must reflect the presence of short-lived nuclides in the early Solar System.^[5]

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]}	Spin and parity ^{[n 7]}^{[n 4]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy^{[n 4]}			Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 4]}	Normal proportion	Range of variation
⁹¹Pd	46	45	90.94911(61)#	10# ms [>1.5 μs]	β⁺	⁹¹Rh	7/2+#
⁹²Pd	46	46	91.94042(54)#	1.1(3) s [0.7(+4−2) s]	β⁺	⁹²Rh	0+
⁹³Pd	46	47	92.93591(43)#	1.07(12) s	β⁺	⁹³Rh	(9/2+)
^93mPd	0+X keV			9.3(+25−17) s
⁹⁴Pd	46	48	93.92877(43)#	9.0(5) s	β⁺	⁹⁴Rh	0+
^94mPd	4884.4(5) keV			530(10) ns			(14+)
⁹⁵Pd	46	49	94.92469(43)#	10# s	β⁺	⁹⁵Rh	9/2+#
^95mPd	1860(500)# keV			13.3(3) s	β⁺ (94.1%)	⁹⁵Rh	(21/2+)
					IT (5%)	⁹⁵Pd
					β⁺, p (.9%)	⁹⁴Ru
⁹⁶Pd	46	50	95.91816(16)	122(2) s	β⁺	⁹⁶Rh	0+
^96mPd	2530.8(1) keV			1.81(1) μs			8+
⁹⁷Pd	46	51	96.91648(32)	3.10(9) min	β⁺	⁹⁷Rh	5/2+#
⁹⁸Pd	46	52	97.912721(23)	17.7(3) min	β⁺	⁹⁸Rh	0+
⁹⁹Pd	46	53	98.911768(16)	21.4(2) min	β⁺	⁹⁹Rh	(5/2)+
¹⁰⁰Pd	46	54	99.908506(12)	3.63(9) d	EC	¹⁰⁰Rh	0+
¹⁰¹Pd	46	55	100.908289(19)	8.47(6) h	β⁺	¹⁰¹Rh	5/2+
¹⁰²Pd	46	56	101.905609(3)	Observationally Stable^{[n 8]}			0+	0.0102(1)
¹⁰³Pd^{[n 9]}	46	57	102.906087(3)	16.991(19) d	EC	¹⁰³Rh	5/2+
^103mPd	784.79(10) keV			25(2) ns			11/2−
¹⁰⁴Pd	46	58	103.904036(4)	Stable			0+	0.1114(8)
¹⁰⁵Pd^{[n 10]}	46	59	104.905085(4)	Stable			5/2+	0.2233(8)
¹⁰⁶Pd^{[n 10]}	46	60	105.903486(4)	Stable			0+	0.2733(3)
¹⁰⁷Pd^{[n 11]}	46	61	106.905133(4)	6.5(3)×10⁶ y	β⁻	¹⁰⁷Ag	5/2+	trace^{[n 12]}
^107m1Pd	115.74(12) keV			0.85(10) μs			1/2+
^107m2Pd	214.6(3) keV			21.3(5) s	IT	¹⁰⁷Pd	11/2−
¹⁰⁸Pd^{[n 10]}	46	62	107.903892(4)	Stable			0+	0.2646(9)
¹⁰⁹Pd^{[n 10]}	46	63	108.905950(4)	13.7012(24) h	β⁻	^109mAg	5/2+
^109m1Pd	113.400(10) keV			380(50) ns			1/2+
^109m2Pd	188.990(10) keV			4.696(3) min	IT	¹⁰⁹Pd	11/2−
¹¹⁰Pd^{[n 10]}	46	64	109.905153(12)	Observationally Stable^{[n 13]}			0+	0.1172(9)
¹¹¹Pd	46	65	110.907671(12)	23.4(2) min	β⁻	^111mAg	5/2+
^111mPd	172.18(8) keV			5.5(1) h	IT	¹¹¹Pd	11/2−
^111mPd	172.18(8) keV			5.5(1) h	β⁻	^111mAg	11/2−
¹¹²Pd	46	66	111.907314(19)	21.03(5) h	β⁻	¹¹²Ag	0+
¹¹³Pd	46	67	112.91015(4)	93(5) s	β⁻	^113mAg	(5/2+)
^113mPd	81.1(3) keV			0.3(1) s	IT	¹¹³Pd	(9/2−)
¹¹⁴Pd	46	68	113.910363(25)	2.42(6) min	β⁻	¹¹⁴Ag	0+
¹¹⁵Pd	46	69	114.91368(7)	25(2) s	β⁻	^115mAg	(5/2+)#
^115mPd	89.18(25) keV			50(3) s	β⁻ (92%)	¹¹⁵Ag	(11/2−)#
^115mPd	89.18(25) keV			50(3) s	IT (8%)	¹¹⁵Pd	(11/2−)#
¹¹⁶Pd	46	70	115.91416(6)	11.8(4) s	β⁻	¹¹⁶Ag	0+
¹¹⁷Pd	46	71	116.91784(6)	4.3(3) s	β⁻	^117mAg	(5/2+)
^117mPd	203.2(3) keV			19.1(7) ms	IT	¹¹⁷Pd	(11/2−)#
¹¹⁸Pd	46	72	117.91898(23)	1.9(1) s	β⁻	¹¹⁸Ag	0+
¹¹⁹Pd	46	73	118.92311(32)#	0.92(13) s	β⁻	¹¹⁹Ag
¹²⁰Pd	46	74	119.92469(13)	0.5(1) s	β⁻	¹²⁰Ag	0+
¹²¹Pd	46	75	120.92887(54)#	285 ms	β⁻	¹²¹Ag
¹²²Pd	46	76	121.93055(43)#	175 ms [>300 ns]	β⁻	¹²²Ag	0+
¹²³Pd	46	77	122.93493(64)#	108 ms	β⁻	¹²³Ag
¹²⁴Pd	46	78	123.93688(54)#	38 ms	β⁻	¹²⁴Ag	0+
¹²⁵Pd^[6]	46	79		57 ms	β⁻	¹²⁵Ag
¹²⁶Pd^[7]^[8]	46	80		48.6 ms	β⁻	¹²⁶Ag	0+
^126m1Pd	2023 keV			330 ns	IT	¹²⁶Pd	5−
^126m2Pd	2110 keV			440 ns	IT	^126m1Pd	7−
¹²⁷Pd	46	81		38 ms	β⁻	¹²⁷Ag
¹²⁸Pd^[7]^[8]	46	82		35 ms	β⁻	¹²⁸Ag	0+
^128mPd	2151 keV			5.8 μs	IT	¹²⁸Pd	8+
¹²⁹Pd	46	83		31 ms	β⁻	¹²⁹Ag
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Palladium-103

Palladium-103 is a radioisotope of the element palladium that has uses in radiation therapy for prostate cancer and uveal melanoma. Palladium-103 may be created from palladium-102 or from rhodium-103 using a cyclotron. Palladium-103 has a half-life of 16.99^[9] days and decays by electron capture to rhodium-103, emitting characteristic x-rays with 21 keV of energy.

Palladium-107

Long-lived fission products
v
t
e
Nuclide	t_1⁄2	Yield	Q^{[a 1]}	βγ
	(Ma)	(%)^{[a 2]}	(keV)
⁹⁹Tc	0.211	6.1385	294	β
¹²⁶Sn	0.230	0.1084	4050^{[a 3]}	βγ
⁷⁹Se	0.327	0.0447	151	β
¹³⁵Cs	1.33	6.9110^{[a 4]}	269	β
⁹³Zr	1.53	5.4575	91	βγ
¹⁰⁷Pd	6.5	1.2499	33	β
¹²⁹I	15.7	0.8410	194	βγ

Palladium-107 is the second-longest lived (half-life of 6.5 million years^[9]) and least radioactive (decay energy only 33 keV, specific activity 5×10⁻⁵ Ci/g) of the 7 long-lived fission products. It undergoes pure beta decay (without gamma radiation) to ¹⁰⁷Ag, which is stable.

Its yield from thermal neutron fission of uranium-235 is 0.1629% per fission^{[citation needed]}, only 1/4 that of iodine-129, and only 1/40 those of ⁹⁹Tc, ⁹³Zr, and ¹³⁵Cs. Yield from ²³³U is slightly lower, but yield from ²³⁹Pu is much higher, 3.3%. Fast fission or fission of some heavier actinides^[which?] will produce palladium-107 at higher yields.

One source^[10] estimates that palladium produced from fission contains the isotopes ¹⁰⁴Pd (16.9%),¹⁰⁵Pd (29.3%), ¹⁰⁶Pd (21.3%), ¹⁰⁷Pd (17%), ¹⁰⁸Pd (11.7%) and ¹¹⁰Pd (3.8%). According to another source, the proportion of ¹⁰⁷Pd is 9.2% for palladium from thermal neutron fission of ²³⁵U, 11.8% for ²³³U, and 20.4% for ²³⁹Pu (and the ²³⁹Pu yield of palladium is about 10 times that of ²³⁵U).

Because of this dilution and because ¹⁰⁵Pd has 11 times the neutron absorption cross section, ¹⁰⁷Pd is not amenable to disposal by nuclear transmutation. However, as a noble metal, palladium is not as mobile in the environment as iodine or technetium.

References

Patent application for Palladium-103 implantable radiation-delivery device^{[permanent dead link]} (accessed 12/7/05)

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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Isotopes of palladium

Contents

List of isotopes

Palladium-103

Palladium-107

References