Isotopes of palladium

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 30 minutes except ¹⁰¹Pd (half-life: 8.47 hours), ¹⁰⁹Pd (half-life: 13.7 hours), and ¹¹²Pd (half-life: 21 hours).

Isotopes of palladium (₄₆Pd)

Main isotopes[1] Decay abun­dance half-life (t1/2) mode pro­duct 100Pd synth 3.63 d ε 100Rh γ – 102Pd 1.02% stable 103Pd synth 16.991 d ε 103Rh 104Pd 11.1% stable 105Pd 22.3% stable 106Pd 27.3% stable 107Pd trace 6.5×106 y β− 107Ag 108Pd 26.5% stable 110Pd 11.7% stable
Standard atomic weight Ar°(Pd)
	106.42±0.01[2] 106.42±0.01 (abridged)[3]
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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)[6] [n 2][n 3]	Half-life[1] [n 4]	Decay mode[1] [n 5]	Daughter isotope [n 6]	Spin and parity[1] [n 7][n 4]	Natural abundance (mole fraction)
	Excitation energy[n 4]							Normal proportion[1]	Range of variation
90Pd	46	44	89.95737(43)#	10# ms [>400 ns]	β+?	90Rh	0+
					β+, p?	89Ru
					2p?	88Ru
91Pd	46	45	90.95044(45)#	32(3) ms	β+ (96.9%)	91Rh	7/2+#
					β+, p (3.1%)	90Ru
92Pd	46	46	91.94119(37)	1.06(3) s	β+ (98.4%)	92Rh	0+
					β+, p (1.6%)	91Ru
93Pd	46	47	92.93668(40)	1.17(2) s	β+ (92.6%)	93Rh	(9/2+)
					β+, p (7.4%)	91Ru
94Pd	46	48	93.9290363(46)	9.1(3) s	β+ (>99.87%)	94Rh	0+
					β+, p (<0.13%)	93Ru
94m1Pd	4883.1(4) keV			515(1) ns	IT	94Pd	(14+)
94m2Pd	7209.8(8) keV			206(18) ns	IT	94Pd	(19−)
95Pd	46	49	94.9248885(33)	7.4(4) s	β+ (99.77%)	95Rh	9/2+#
					β+, p (0.23%)	95Rh
95mPd	1875.13(14) keV			13.3(2) s	β+ (88%)	95Rh	(21/2+)
					IT (11%)	95Pd
					β+, p (0.71%)	94Ru
96Pd	46	50	95.9182137(45)	122(2) s	β+	96Rh	0+
96mPd	2530.57(23) keV			1.804(7) μs	IT	96Pd	8+#
97Pd	46	51	96.9164720(52)	3.10(9) min	β+	97Rh	5/2+#
98Pd	46	52	97.9126983(51)	17.7(4) min	β+	98Rh	0+
99Pd	46	53	98.9117731(55)	21.4(2) min	β+	99Rh	(5/2)+
100Pd	46	54	99.908520(19)	3.63(9) d	EC	100Rh	0+
101Pd	46	55	100.9082848(49)	8.47(6) h	β+	101Rh	5/2+
102Pd	46	56	101.90563229(45)	Observationally Stable[n 8]			0+	0.0102(1)
103Pd	46	57	102.90611107(94)	16.991(19) d	EC	103Rh	5/2+
104Pd	46	58	103.9040304(14)	Stable			0+	0.1114(8)
105Pd[n 9]	46	59	104.9050795(12)	Stable			5/2+	0.2233(8)
105mPd	489.1(3) keV			35.5(5) μs	IT	105Pd	11/2−
106Pd[n 9]	46	60	105.9034803(12)	Stable			0+	0.2733(3)
107Pd[n 10]	46	61	106.9051281(13)	6.5(3)×106 y	β−	107Ag	5/2+	trace[n 11]
107m1Pd	115.74(12) keV			0.85(10) μs	IT	107Pd	1/2+
107m2Pd	214.6(3) keV			21.3(5) s	IT	107Pd	11/2−
108Pd[n 9]	46	62	107.9038918(12)	Stable			0+	0.2646(9)
109Pd[n 9]	46	63	108.9059506(12)	13.59(12) h	β−	109Ag	5/2+
109m1Pd	113.4000(14) keV			380(50) ns	IT	109Pd	1/2+
109m2Pd	188.9903(10) keV			4.703(9) min	IT	109Pd	11/2−
110Pd[n 9]	46	64	109.90517288(66)	Observationally Stable[n 12]			0+	0.1172(9)
111Pd	46	65	110.90769036(79)	23.56(9) min	β−	111Ag	5/2+
111mPd	172.18(8) keV			5.563(13) h	IT (76.8%)	111Pd	11/2−
					β− (23.2%)	111Ag
112Pd	46	66	111.9073306(70)	21.04(17) h	β−	112Ag	0+
113Pd	46	67	112.9102619(75)	93(5) s	β−	113Ag	(5/2+)
113mPd	81.1(3) keV			0.3(1) s	IT	113Pd	(9/2−)
114Pd	46	68	113.9103694(75)	2.42(6) min	β−	114Ag	0+
115Pd	46	69	114.9136650(19)[7]	25(2) s	β−	115Ag	(1/2)+
115mPd	86.8(29) keV[7]			50(3) s	β− (92.0%)	115Ag	(7/2−)
					IT (8.0%)	115Pd
116Pd	46	70	115.9142979(77)	11.8(4) s	β−	116Ag	0+
117Pd	46	71	116.9179556(78)	4.3(3) s	β−	117Ag	(3/2+)
117mPd	203.3(3) keV			19.1(7) ms	IT	117Pd	(9/2−)
118Pd	46	72	117.9190673(27)	1.9(1) s	β−	118Ag	0+
119Pd	46	73	118.9231238(45)[7]	0.88(2) s	β−	119Ag	1/2+, 3/2+[8]
					β−, n?	118Ag
119mPd[7]	199.1(30) keV			0.85(1) s	IT	119Pd	(11/2−)[8]
120Pd	46	74	119.9245517(25)	492(33) ms	β− (>99.3%)	120Ag	0+
					β−, n (<0.7%)	119Ag
121Pd	46	75	120.9289513(40)[7]	290(1) ms	β− (>99.2%)	121Ag	3/2+#
					β−, n (<0.8%)	120Ag
121m1Pd	135.5(5) keV			460(90) ns	IT	121Pd	7/2+#
121m2Pd	160(14) keV			460(90) ns	IT	121Pd	11/2−#
122Pd	46	76	121.930632(21)	193(5) ms	β−	122Ag	0+
					β−, n (<2.5%)	121Ag
123Pd	46	77	122.93513(85)	108(1) ms	β− (90%)	123Ag	3/2+#
					β−, n (10%)	122Ag
123mPd	100(50)# keV			100# ms	β−	123Ag	11/2−#
					IT?	123Pd
124Pd	46	78	123.93731(32)#	88(15) ms	β− (83%)	124Ag	0+
					β−, n (17%)	123Ag
124mPd	1000(800)# keV			>20 μs	IT	124Pd	11/2−#
125Pd	46	79	124.94207(43)#	60(6) ms	β− (88%)	125Ag	3/2+#
					β−, n (12%)	124Ag
125m1Pd	100(50)# keV			50# ms	β−	125Ag	11/2−#
					IT?	125Pd
125m2Pd	1805.23(18) keV			144(4) ns	IT	125Pd	(23/2+)
126Pd	46	80	125.94440(43)#	48.6(8) ms	β− (78%)	126Ag	0+
					β−, n (22%)	125Ag
126m1Pd	2023.5(7) keV			330(40) ns	IT	126Pd	(5−)
126m2Pd	2109.7(9) keV			440(30) ns	IT	126Pd	(7−)
126m3Pd	2406.0(10) keV			23.0(8) ms	β− (72%)	126Ag	(10+)
					IT (28%)	126Pd
127Pd	46	81	126.94931(54)#	38(2) ms	β− (>81%)	127Ag	11/2−#
					β−, n (<19%)	126Ag
					β−, 2n?	125Ag
127mPd	1717.91(23) keV			39(6) μs	IT	127Pd	(19/2+)
128Pd	46	82	127.95235(54)#	35(3) ms	β−	128Ag	0+
					β−, n?	127Ag
128mPd	2151.0(10) keV			5.8(8) μs	IT	128Pd	(8+)
129Pd	46	83	128.95933(64)#	31(7) ms	β−	129Ag	7/2−#
					β−, n?	128Ag
					β−, 2n?	127Ag
130Pd	46	84	129.96486(32)#	27# ms [>550 ns]	β−	130Ag	0+
					β−, n?	129Ag
					β−, 2n?	128Ag
131Pd	46	85	130.97237(32)#	20# ms [>550 ns]	β−	131Ag	7/2−#
					β−, n?	130Ag
					β−, 2n?	129Ag
This table header & footer: view

1. ^mPd – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
5. Modes of decay:

   EC:	Electron capture
   IT:	Isomeric transition
   p:	Proton emission

6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.
8. Believed to decay by β⁺β⁺ to ¹⁰²Ru with a half-life over 7.6×10¹⁸ y
9. Fission product
10. Long-lived fission product
11. Cosmogenic nuclide, also found as nuclear contamination
12. Believed to decay by β⁻β⁻ to ¹¹⁰Cd with a half-life over 2.9×10²⁰ years

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	t1⁄2	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	16.14	0.8410	194	βγ
Decay energy is split among β, neutrino, and γ if any. Per 65 thermal neutron fissions of 235U and 35 of 239Pu. Has decay energy 380 keV, but its decay product 126Sb has decay energy 3.67 MeV. Lower in thermal reactors because 135Xe, its predecessor, readily absorbs neutrons.

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 0.14% per fission,^[10] 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, 3.2%.^[10] Fast fission or fission of some heavier actinides^[which?] will produce palladium-107 at higher yields.

One source^[11] 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)

1. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
2. "Standard Atomic Weights: Palladium". CIAAW. 1979.
3. Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
4. W. R. Kelly; G. J. Wasserburg (1978). "Evidence for the existence of ¹⁰⁷Pd in the early solar system". Geophysical Research Letters. 5 (12): 1079–1082. Bibcode:1978GeoRL...5.1079K. doi:10.1029/GL005i012p01079.
5. J. H. Chen; G. J. Wasserburg (1990). "The isotopic composition of Ag in meteorites and the presence of ¹⁰⁷Pd in protoplanets". Geochimica et Cosmochimica Acta. 54 (6): 1729–1743. Bibcode:1990GeCoA..54.1729C. doi:10.1016/0016-7037(90)90404-9.
6. Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
7. Jaries, A.; Stryjczyk, M.; Kankainen, A.; Ayoubi, L. Al; Beliuskina, O.; Canete, L.; de Groote, R. P.; Delafosse, C.; Delahaye, P.; Eronen, T.; Flayol, M.; Ge, Z.; Geldhof, S.; Gins, W.; Hukkanen, M.; Imgram, P.; Kahl, D.; Kostensalo, J.; Kujanpää, S.; Kumar, D.; Moore, I. D.; Mougeot, M.; Nesterenko, D. A.; Nikas, S.; Patel, D.; Penttilä, H.; Pitman-Weymouth, D.; Pohjalainen, I.; Raggio, A.; Ramalho, M.; Reponen, M.; Rinta-Antila, S.; de Roubin, A.; Ruotsalainen, J.; Srivastava, P. C.; Suhonen, J.; Vilen, M.; Virtanen, V.; Zadvornaya, A. "Physical Review C - Accepted Paper: Isomeric states of fission fragments explored via Penning trap mass spectrometry at IGISOL". journals.aps.org. arXiv:2403.04710.
8. Kurpeta, J.; Abramuk, A.; Rząca-Urban, T.; Urban, W.; Canete, L.; Eronen, T.; Geldhof, S.; Gierlik, M.; Greene, J. P.; Jokinen, A.; Kankainen, A.; Moore, I. D.; Nesterenko, D. A.; Penttilä, H.; Pohjalainen, I.; Reponen, M.; Rinta-Antila, S.; de Roubin, A.; Simpson, G. S.; Smith, A. G.; Vilén, M. (14 March 2022). "β - and γ -spectroscopy study of Pd 119 and Ag 119". Physical Review C. 105 (3). doi:10.1103/PhysRevC.105.034316.
9. Winter, Mark. "Isotopes of palladium". WebElements. The University of Sheffield and WebElements Ltd, UK. Retrieved 4 March 2013.
10. Weller, A.; Ramaker, T.; Stäger, F.; Blenke, T.; Raiwa, M.; Chyzhevskyi, I.; Kirieiev, S.; Dubchak, S.; Steinhauser, G. (2021). "Detection of the Fission Product Palladium-107 in a Pond Sediment Sample from Chernobyl". Environmental Science & Technology Letters. 8 (8): 656–661. Bibcode:2021EnSTL...8..656W. doi:10.1021/acs.estlett.1c00420.
11. R. P. Bush (1991). "Recovery of Platinum Group Metals from High Level Radioactive Waste" (PDF). Platinum Metals Review. 35 (4): 202–208. doi:10.1595/003214091X354202208. Archived from the original (PDF) on 2015-09-24. Retrieved 2011-04-02.

• 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.