Isotopes of palladium

Naturally occurring palladium (Pd) is composed of six stable isotopes, ¹⁰²Pd, ¹⁰⁴Pd, ¹⁰⁵Pd, ¹⁰⁶Pd, ¹⁰⁸Pd, and ¹¹⁰Pd. 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 123.937 u (¹²⁴Pd). 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, California meteorite of 1978.^[1] 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.^[2]

Standard atomic mass: 106.42(1) u

1 Palladium-103
2 Palladium-107
3 Table
- 3.1 Notes
4 References

Palladium-103

Palladium-103 is a radioisotope of the element palladium which has uses in radiation therapy for prostate cancer and uveal melanoma. Palladium-103 may be created from palladium-102. It has a half-life of 16.99^[3] days and decays by electron capture to rhodium-103, emitting gamma-rays with 21 keV of energy.

Palladium-107

Long-lived
fission products
Prop: Unit:	t^½ Ma	Yield %	Q * KeV	βγ *
⁹⁹Tc	0.211	6.1385	294	β
¹²⁶Sn	0.230	0.1084	4050	βγ
⁷⁹Se	0.327	0.0447	151	β
⁹³Zr	1.53	5.4575	91	βγ
¹³⁵Cs	2.3	6.9110	269	β
¹⁰⁷Pd	6.5	1.2499	33	β
¹²⁹I	15.7	0.8410	194	βγ

Palladium-107 is the second longest lived (halflife of 6.5 million years^[3]) 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 (no gamma radiation) to Ag-107.

Its yield from thermal neutron fission of uranium-235 is 0.1629% per fission, only 1/4 that of iodine-129, and only 1/40 those of Tc-99, Zr-93, and Cs-135. Yield from U-233 is slightly lower, but yield from Pu-239 is much higher, 3.3%. Yields are higher in fast fission or in fission of heavier nuclei.

According to ^[4] fission palladium 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 U-235, 11.8% for U-233, and 20.4% for Pu-239. (and the Pu-239 yield of palladium is about 10 times that of U-235.)

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.

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)^[5]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life	decay mode(s)^[5]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
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 3]}			0+	0.0102(1)
¹⁰³Pd^{[n 4]}	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)	Observationally Stable^{[n 5]}			0+	0.1114(8)
¹⁰⁵Pd^{[n 6]}	46	59	104.905085(4)	Observationally Stable^{[n 5]}			5/2+	0.2233(8)
¹⁰⁶Pd^{[n 6]}	46	60	105.903486(4)	Observationally Stable^{[n 5]}			0+	0.2733(3)
¹⁰⁷Pd^{[n 7]}	46	61	106.905133(4)	6.5(3)×10⁶ a	β^-	¹⁰⁷Ag	5/2+
^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 6]}	46	62	107.903892(4)	Observationally Stable^{[n 5]}			0+	0.2646(9)
¹⁰⁹Pd^{[n 6]}	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 6]}	46	64	109.905153(12)	Observationally Stable^{[n 8]}			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)#	400# ms [>300 ns]	β^-	¹²¹Ag
¹²²Pd	46	76	121.93055(43)#	300# ms [>300 ns]	β^-	¹²²Ag	0+
¹²³Pd	46	77	122.93493(64)#	200# ms [>300 ns]	β^-	¹²³Ag
¹²⁴Pd	46	78	123.93688(54)#	100# ms [>300 ns]			0+

^ Abbreviations:
EC: Electron capture
IT: Isomeric transition
^ Bold for stable isotopes
^ Believed to decay by β⁺β⁺ to ¹⁰²Ru
^ Used in medicine
^ ^a ^b ^c ^d Theoretically capable of spontaneous fission
^ ^a ^b ^c ^d ^e Fission product
^ Long-lived fission product
^ Believed to decay by β^-β^- to ¹¹⁰Cd with a half-life over 600×10¹⁵ years

Notes

The precision of the isotope abundances and atomic mass is limited through variations. The given ranges should be applicable to any normal terrestrial material.
Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References

Patent application for Palladium-103 implantable radiation-delivery device (accessed 12/7/05)

^ 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.
^ ^a ^b http://www.chemicalelements.com/elements/pd.html
^ http://www.platinummetalsreview.com/pdf/pmr-v35-i4-202-208.pdf
^ http://www.nucleonica.net/unc.aspx

Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683. http://www.iupac.org/publications/pac/75/6/0683/pdf/.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. http://iupac.org/publications/pac/78/11/2051/pdf/. Lay summary.
Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/. Retrieved September 2005.
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0849304859.

Isotopes of rhodium	Isotopes of palladium	Isotopes of silver
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