Isotopes of palladium

Isotopes of palladium (₄₆Pd)
γ	–
Standard atomic weight Ar°(Pd)
	106.42±0.01; 106.42±0.01 (abridged);
	view; talk; edit;

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).

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
This table header & footer: view

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

EC: Electron capture

IT: Isomeric transition

p: Proton emission
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) spin value – Indicates spin with weak assignment arguments.
^ Believed to decay by β⁺β⁺ to ¹⁰²Ru
^ Used in medicine
^ ^a ^b ^c ^d ^e Fission product
^ Long-lived fission product
^ Cosmogenic nuclide, also found as nuclear contamination
^ Believed to decay by β⁻β⁻ to ¹¹⁰Cd with a half-life over 6×10¹⁷ 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	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
^ 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)

^ 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.
^ "Standard Atomic Weights: Palladium". CIAAW. 1979.
^ 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.
^ 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.
^ 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.
^ Future Plan of the Experimental Program on Synthesizing the Heaviest Element at RIKEN, Kosuke Morita Archived September 17, 2012, at the Wayback Machine
^ ^a ^b H. Watanabe; et al. (2013-10-08). "Isomers in ¹²⁸Pd and ¹²⁶Pd: Evidence for a Robust Shell Closure at the Neutron Magic Number 82 in Exotic Palladium Isotopes" (PDF). Physical Review Letters. 111 (15): 152501. Bibcode:2013PhRvL.111o2501W. doi:10.1103/PhysRevLett.111.152501. hdl:2437/215438. PMID 24160593.
^ ^a ^b "Experiments on neutron-rich atomic nuclei could help scientists to understand nuclear reactions in exploding stars". phys.org. 2013-11-29.
^ ^a ^b Winter, Mark. "Isotopes of palladium". WebElements. The University of Sheffield and WebElements Ltd, UK. Retrieved 4 March 2013.
^ ^a ^b 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.
^ 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.

[6] Pd – Excited nuclear isomer.

[7] ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-8] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[TNN-9] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[10] Modes of decay:

EC: Electron capture

IT: Isomeric transition

p: Proton emission

[11] Bold symbol as daughter – Daughter product is stable.

[12] ( ) spin value – Indicates spin with weak assignment arguments.

[13] Believed to decay by β⁺β⁺ to ¹⁰²Ru

[14] Used in medicine

[FP-15] Fission product

[16] Long-lived fission product

[17] Cosmogenic nuclide, also found as nuclear contamination

[18] Believed to decay by β⁻β⁻ to ¹¹⁰Cd with a half-life over 6×10¹⁷ years

[23] Decay energy is split among β, neutrino, and γ if any.

[24] Per 65 thermal neutron fissions of ²³⁵U and 35 of ²³⁹Pu.

[25] Has decay energy 380 keV, but its decay product ¹²⁶Sb has decay energy 3.67 MeV.

[26] Lower in thermal reactors because ¹³⁵Xe, its predecessor, readily absorbs neutrons.

[NUBASE2020-1] 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.

[CIAAW2021-3] 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.

[19] Future Plan of the Experimental Program on Synthesizing the Heaviest Element at RIKEN, Kosuke Morita Archived September 17, 2012, at the Wayback Machine

[NM126A-20] H. Watanabe; et al. (2013-10-08). "Isomers in ¹²⁸Pd and ¹²⁶Pd: Evidence for a Robust Shell Closure at the Neutron Magic Number 82 in Exotic Palladium Isotopes" (PDF). Physical Review Letters. 111 (15): 152501. Bibcode:2013PhRvL.111o2501W. doi:10.1103/PhysRevLett.111.152501. hdl:2437/215438. PMID 24160593.

[NM126B-21] "Experiments on neutron-rich atomic nuclei could help scientists to understand nuclear reactions in exploding stars". phys.org. 2013-11-29.

[webelements-22] Winter, Mark. "Isotopes of palladium". WebElements. The University of Sheffield and WebElements Ltd, UK. Retrieved 4 March 2013.

[Pd107-2021-27] 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.

[28] 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.

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