# Isotopes of palladium

Natural palladium ($_{46}$Pd) is composed of six stable isotopes, $^{102}$Pd, $^{104}$Pd, $^{105}$Pd, $^{106}$Pd, $^{108}$Pd, and $^{110}$Pd, although $^{102}$Pd and $^{110}$Pd are theoretically unstable. The most stable radioisotopes are $^{107}$Pd with a half-life of 6.5 million years, $^{103}$Pd with a half-life of 17 days, and $^{100}$Pd with a half-life of 3.63 days. Twenty-three other radioisotopes have been characterized with atomic weights ranging from 90.949 u ($^{91}$Pd) to 128.96 u ($^{129}$Pd). Most of these have half-lives that are less than 30 minutes except $^{101}$Pd (half-life: 8.47 hours), $^{109}$Pd (half-life: 13.7 hours), and $^{112}$Pd (half-life: 21 hours).
The primary decay mode before the most abundant stable isotope, $^{106}$Pd, is electron capture and the primary mode after is beta decay. The primary decay product before $^{106}$Pd is rhodium and the primary product after is silver.
Radiogenic $^{107}$Ag is a decay product of $^{107}$Pd and was first discovered in the Santa Clara meteorite of 1978. The discoverers suggest that the coalescence and differentiation of iron-cored small planets may have occurred 10 million years after a nucleosynthetic event. $^{107}$Pd 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.

## List of isotopes

| Nuclide | Z | N | Isotopic mass (Da) | Half-life | Decay mode | Daughter isotope | Spin and parity | Natural abundance (mole fraction) | Natural abundance (mole fraction) |
| Nuclide | Excitation energy | Excitation energy | Excitation energy | Half-life | Decay mode | Daughter isotope | Spin and parity | Normal proportion | Range of variation |
| $^{90}$Pd | 46 | 44 | 89.95737(43)# | 10# ms [>400 ns] | β$^+$? | $^{90}$Rh | 0+ | | |
| $^{90}$Pd | 46 | 44 | 89.95737(43)# | 10# ms [>400 ns] | β$^+$, p? | $^{89}$Ru | 0+ | | |
| $^{90}$Pd | 46 | 44 | 89.95737(43)# | 10# ms [>400 ns] | 2p? | $^{88}$Ru | 0+ | | |
| $^{91}$Pd | 46 | 45 | 90.95044(45)# | 32(3) ms | β$^+$ (96.9%) | $^{91}$Rh | 7/2+# | | |
| $^{91}$Pd | 46 | 45 | 90.95044(45)# | 32(3) ms | β$^+$, p (3.1%) | $^{90}$Ru | 7/2+# | | |
| $^{92}$Pd | 46 | 46 | 91.94119(37) | 1.06(3) s | β$^+$ (98.4%) | $^{92}$Rh | 0+ | | |
| $^{92}$Pd | 46 | 46 | 91.94119(37) | 1.06(3) s | β$^+$, p (1.6%) | $^{91}$Ru | 0+ | | |
| $^{93}$Pd | 46 | 47 | 92.93668(40) | 1.17(2) s | β$^+$ (92.6%) | $^{93}$Rh | (9/2+) | | |
| $^{93}$Pd | 46 | 47 | 92.93668(40) | 1.17(2) s | β$^+$, p (7.4%) | $^{92}$Ru | (9/2+) | | |
| $^{94}$Pd | 46 | 48 | 93.9290363(46) | 9.1(3) s | β$^+$ (>99.87%) | $^{94}$Rh | 0+ | | |
| $^{94}$Pd | 46 | 48 | 93.9290363(46) | 9.1(3) s | β$^+$, p (<0.13%) | $^{93}$Ru | 0+ | | |
| $^{94m1}$Pd | 4883.1(4) keV | 4883.1(4) keV | 4883.1(4) keV | 515(1) ns | IT | $^{94}$Pd | (14+) | | |
| $^{94m2}$Pd | 7209.8(8) keV | 7209.8(8) keV | 7209.8(8) keV | 206(18) ns | IT | $^{94}$Pd | (19−) | | |
| $^{95}$Pd | 46 | 49 | 94.9248885(33) | 7.4(4) s | β$^+$ (99.77%) | $^{95}$Rh | 9/2+# | | |
| $^{95}$Pd | 46 | 49 | 94.9248885(33) | 7.4(4) s | β$^+$, p (0.23%) | $^{94}$Ru | 9/2+# | | |
| $^{95m}$Pd | 1875.13(14) keV | 1875.13(14) keV | 1875.13(14) keV | 13.3(2) s | β$^+$ (88%) | $^{95}$Rh | (21/2+) | | |
| $^{95m}$Pd | 1875.13(14) keV | 1875.13(14) keV | 1875.13(14) keV | 13.3(2) s | IT (11%) | $^{95}$Pd | (21/2+) | | |
| $^{95m}$Pd | 1875.13(14) keV | 1875.13(14) keV | 1875.13(14) keV | 13.3(2) s | β$^+$, p (0.71%) | $^{94}$Ru | (21/2+) | | |
| $^{96}$Pd | 46 | 50 | 95.9182137(45) | 122(2) s | β$^+$ | $^{96}$Rh | 0+ | | |
| $^{96m}$Pd | 2530.57(23) keV | 2530.57(23) keV | 2530.57(23) keV | 1.804(7) μs | IT | $^{96}$Pd | 8+# | | |
| $^{97}$Pd | 46 | 51 | 96.9164720(52) | 3.10(9) min | β$^+$ | $^{97}$Rh | 5/2+# | | |
| $^{98}$Pd | 46 | 52 | 97.9126983(51) | 17.7(4) min | β$^+$ | $^{98}$Rh | 0+ | | |
| $^{99}$Pd | 46 | 53 | 98.9117731(55) | 21.4(2) min | β$^+$ | $^{99}$Rh | (5/2)+ | | |
| $^{100}$Pd | 46 | 54 | 99.908520(19) | 3.63(9) d | EC | $^{100}$Rh | 0+ | | |
| $^{101}$Pd | 46 | 55 | 100.9082848(49) | 8.47(6) h | β$^+$ | $^{101}$Rh | 5/2+ | | |
| $^{102}$Pd | 46 | 56 | 101.90563229(45) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.0102(1) | |
| $^{103}$Pd | 46 | 57 | 102.90611107(94) | 16.991(19) d | EC | $^{103}$Rh | 5/2+ | | |
| $^{104}$Pd | 46 | 58 | 103.9040304(14) | Stable | Stable | Stable | 0+ | 0.1114(8) | |
| $^{105}$Pd | 46 | 59 | 104.9050795(12) | Stable | Stable | Stable | 5/2+ | 0.2233(8) | |
| $^{105m}$Pd | 489.1(3) keV | 489.1(3) keV | 489.1(3) keV | 35.5(5) μs | IT | $^{105}$Pd | 11/2− | | |
| $^{106}$Pd | 46 | 60 | 105.9034803(12) | Stable | Stable | Stable | 0+ | 0.2733(3) | |
| $^{107}$Pd | 46 | 61 | 106.9051281(13) | 6.5(3)×10$^6$ y | β$^−$ | $^{107}$Ag | 5/2+ | trace | |
| $^{107m1}$Pd | 115.74(12) keV | 115.74(12) keV | 115.74(12) keV | 0.85(10) μs | IT | $^{107}$Pd | 1/2+ | | |
| $^{107m2}$Pd | 214.6(3) keV | 214.6(3) keV | 214.6(3) keV | 21.3(5) s | IT | $^{107}$Pd | 11/2− | | |
| $^{108}$Pd | 46 | 62 | 107.9038918(12) | Stable | Stable | Stable | 0+ | 0.2646(9) | |
| $^{109}$Pd | 46 | 63 | 108.9059506(12) | 13.59(12) h | β$^−$ | $^{109}$Ag | 5/2+ | | |
| $^{109m1}$Pd | 113.4000(14) keV | 113.4000(14) keV | 113.4000(14) keV | 380(50) ns | IT | $^{109}$Pd | 1/2+ | | |
| $^{109m2}$Pd | 188.9903(10) keV | 188.9903(10) keV | 188.9903(10) keV | 4.703(9) min | IT | $^{109}$Pd | 11/2− | | |
| $^{110}$Pd | 46 | 64 | 109.90517288(66) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.1172(9) | |
| $^{111}$Pd | 46 | 65 | 110.90769036(79) | 23.56(9) min | β$^−$ | $^{111}$Ag | 5/2+ | | |
| $^{111m}$Pd | 172.18(8) keV | 172.18(8) keV | 172.18(8) keV | 5.563(13) h | IT (76.8%) | $^{111}$Pd | 11/2− | | |
| $^{111m}$Pd | 172.18(8) keV | 172.18(8) keV | 172.18(8) keV | 5.563(13) h | β$^−$ (23.2%) | $^{111}$Ag | 11/2− | | |
| $^{112}$Pd | 46 | 66 | 111.9073306(70) | 21.04(17) h | β$^−$ | $^{112}$Ag | 0+ | | |
| $^{113}$Pd | 46 | 67 | 112.9102619(75) | 93(5) s | β$^−$ | $^{113}$Ag | (5/2+) | | |
| $^{113m}$Pd | 81.1(3) keV | 81.1(3) keV | 81.1(3) keV | 0.3(1) s | IT | $^{113}$Pd | (9/2−) | | |
| $^{114}$Pd | 46 | 68 | 113.9103694(75) | 2.42(6) min | β$^−$ | $^{114}$Ag | 0+ | | |
| $^{115}$Pd | 46 | 69 | 114.9136650(19) | 25(2) s | β$^−$ | $^{115}$Ag | (1/2)+ | | |
| $^{115m}$Pd | 86.8(29) keV | 86.8(29) keV | 86.8(29) keV | 50(3) s | β$^−$ (92.0%) | $^{115}$Ag | (7/2−) | | |
| $^{115m}$Pd | 86.8(29) keV | 86.8(29) keV | 86.8(29) keV | 50(3) s | IT (8.0%) | $^{115}$Pd | (7/2−) | | |
| $^{116}$Pd | 46 | 70 | 115.9142979(77) | 11.8(4) s | β$^−$ | $^{116}$Ag | 0+ | | |
| $^{117}$Pd | 46 | 71 | 116.9179556(78) | 4.3(3) s | β$^−$ | $^{117}$Ag | (3/2+) | | |
| $^{117m}$Pd | 203.3(3) keV | 203.3(3) keV | 203.3(3) keV | 19.1(7) ms | IT | $^{117}$Pd | (9/2−) | | |
| $^{118}$Pd | 46 | 72 | 117.9190673(27) | 1.9(1) s | β$^−$ | $^{118}$Ag | 0+ | | |
| $^{119}$Pd | 46 | 73 | 118.9231238(45) | 0.88(2) s | β$^−$ | $^{119}$Ag | 1/2+, 3/2+ | | |
| $^{119}$Pd | 46 | 73 | 118.9231238(45) | 0.88(2) s | β$^−$, n? | $^{118}$Ag | 1/2+, 3/2+ | | |
| $^{119m}$Pd | 199.1(30) keV | 199.1(30) keV | 199.1(30) keV | 0.85(1) s | IT | $^{119}$Pd | (11/2−) | | |
| $^{120}$Pd | 46 | 74 | 119.9245517(25) | 492(33) ms | β$^−$ (>99.3%) | $^{120}$Ag | 0+ | | |
| $^{120}$Pd | 46 | 74 | 119.9245517(25) | 492(33) ms | β$^−$, n (<0.7%) | $^{119}$Ag | 0+ | | |
| $^{121}$Pd | 46 | 75 | 120.9289513(40) | 290(1) ms | β$^−$ (>99.2%) | $^{121}$Ag | 3/2+# | | |
| $^{121}$Pd | 46 | 75 | 120.9289513(40) | 290(1) ms | β$^−$, n (<0.8%) | $^{120}$Ag | 3/2+# | | |
| $^{121m1}$Pd | 135.5(5) keV | 135.5(5) keV | 135.5(5) keV | 460(90) ns | IT | $^{121}$Pd | 7/2+# | | |
| $^{121m2}$Pd | 160(14) keV | 160(14) keV | 160(14) keV | 460(90) ns | IT | $^{121}$Pd | 11/2−# | | |
| $^{122}$Pd | 46 | 76 | 121.930632(21) | 193(5) ms | β$^−$ | $^{122}$Ag | 0+ | | |
| $^{122}$Pd | 46 | 76 | 121.930632(21) | 193(5) ms | β$^−$, n (<2.5%) | $^{121}$Ag | 0+ | | |
| $^{123}$Pd | 46 | 77 | 122.93513(85) | 108(1) ms | β$^−$ (90%) | $^{123}$Ag | 3/2+# | | |
| $^{123}$Pd | 46 | 77 | 122.93513(85) | 108(1) ms | β$^−$, n (10%) | $^{122}$Ag | 3/2+# | | |
| $^{123m}$Pd | 100(50)# keV | 100(50)# keV | 100(50)# keV | 100# ms | β$^−$ | $^{123}$Ag | 11/2−# | | |
| $^{123m}$Pd | 100(50)# keV | 100(50)# keV | 100(50)# keV | 100# ms | IT? | $^{123}$Pd | 11/2−# | | |
| $^{124}$Pd | 46 | 78 | 123.93731(32)# | 88(15) ms | β$^−$ (83%) | $^{124}$Ag | 0+ | | |
| $^{124}$Pd | 46 | 78 | 123.93731(32)# | 88(15) ms | β$^−$, n (17%) | $^{123}$Ag | 0+ | | |
| $^{124m}$Pd | 1000(800)# keV | 1000(800)# keV | 1000(800)# keV | >20 μs | IT | $^{124}$Pd | 11/2−# | | |
| $^{125}$Pd | 46 | 79 | 124.94207(43)# | 60(6) ms | β$^−$ (88%) | $^{125}$Ag | 3/2+# | | |
| $^{125}$Pd | 46 | 79 | 124.94207(43)# | 60(6) ms | β$^−$, n (12%) | $^{124}$Ag | 3/2+# | | |
| $^{125m1}$Pd | 100(50)# keV | 100(50)# keV | 100(50)# keV | 50# ms | β$^−$ | $^{125}$Ag | 11/2−# | | |
| $^{125m1}$Pd | 100(50)# keV | 100(50)# keV | 100(50)# keV | 50# ms | IT? | $^{125}$Pd | 11/2−# | | |
| $^{125m2}$Pd | 1805.23(18) keV | 1805.23(18) keV | 1805.23(18) keV | 144(4) ns | IT | $^{125}$Pd | (23/2+) | | |
| $^{126}$Pd | 46 | 80 | 125.94440(43)# | 48.6(8) ms | β$^−$ (78%) | $^{126}$Ag | 0+ | | |
| $^{126}$Pd | 46 | 80 | 125.94440(43)# | 48.6(8) ms | β$^−$, n (22%) | $^{125}$Ag | 0+ | | |
| $^{126m1}$Pd | 2023.5(7) keV | 2023.5(7) keV | 2023.5(7) keV | 330(40) ns | IT | $^{126}$Pd | (5−) | | |
| $^{126m2}$Pd | 2109.7(9) keV | 2109.7(9) keV | 2109.7(9) keV | 440(30) ns | IT | $^{126}$Pd | (7−) | | |
| $^{126m3}$Pd | 2406.0(10) keV | 2406.0(10) keV | 2406.0(10) keV | 23.0(8) ms | β$^−$ (72%) | $^{126}$Ag | (10+) | | |
| $^{126m3}$Pd | 2406.0(10) keV | 2406.0(10) keV | 2406.0(10) keV | 23.0(8) ms | IT (28%) | $^{126}$Pd | (10+) | | |
| $^{127}$Pd | 46 | 81 | 126.94931(54)# | 38(2) ms | β$^−$ (>81%) | $^{127}$Ag | 11/2−# | | |
| $^{127}$Pd | 46 | 81 | 126.94931(54)# | 38(2) ms | β$^−$, n (<19%) | $^{126}$Ag | 11/2−# | | |
| $^{127}$Pd | 46 | 81 | 126.94931(54)# | 38(2) ms | β$^−$, 2n? | $^{125}$Ag | 11/2−# | | |
| $^{127m}$Pd | 1717.91(23) keV | 1717.91(23) keV | 1717.91(23) keV | 39(6) μs | IT | $^{127}$Pd | (19/2+) | | |
| $^{128}$Pd | 46 | 82 | 127.95235(54)# | 35(3) ms | β$^−$ | $^{128}$Ag | 0+ | | |
| $^{128}$Pd | 46 | 82 | 127.95235(54)# | 35(3) ms | β$^−$, n? | $^{127}$Ag | 0+ | | |
| $^{128m}$Pd | 2151.0(10) keV | 2151.0(10) keV | 2151.0(10) keV | 5.8(8) μs | IT | $^{128}$Pd | (8+) | | |
| $^{129}$Pd | 46 | 83 | 128.95933(64)# | 31(7) ms | β$^−$ | $^{129}$Ag | 7/2−# | | |
| $^{129}$Pd | 46 | 83 | 128.95933(64)# | 31(7) ms | β$^−$, n? | $^{128}$Ag | 7/2−# | | |
| $^{129}$Pd | 46 | 83 | 128.95933(64)# | 31(7) ms | β$^−$, 2n? | $^{127}$Ag | 7/2−# | | |
| $^{130}$Pd | 46 | 84 | 129.96486(32)# | 27# ms [>550 ns] | β$^−$ | $^{130}$Ag | 0+ | | |
| $^{130}$Pd | 46 | 84 | 129.96486(32)# | 27# ms [>550 ns] | β$^−$, n? | $^{129}$Ag | 0+ | | |
| $^{130}$Pd | 46 | 84 | 129.96486(32)# | 27# ms [>550 ns] | β$^−$, 2n? | $^{128}$Ag | 0+ | | |
| $^{131}$Pd | 46 | 85 | 130.97237(32)# | 20# ms [>550 ns] | β$^−$ | $^{131}$Ag | 7/2−# | | |
| $^{131}$Pd | 46 | 85 | 130.97237(32)# | 20# ms [>550 ns] | β$^−$, n? | $^{130}$Ag | 7/2−# | | |
| $^{131}$Pd | 46 | 85 | 130.97237(32)# | 20# ms [>550 ns] | β$^−$, 2n? | $^{129}$Ag | 7/2−# | | |
| This table header & footer: view ||||||||||
* ↑ $^m$Pd – 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).
* 1 2 3 # – 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 $^{102}$Ru with a half-life over 7.6×10$^{18}$ y
* 1 2 3 4 5 Fission product
* ↑ Long-lived fission product
* ↑ Cosmogenic nuclide, also found as nuclear contamination
* ↑ Believed to decay by β$^−$β$^−$ to $^{110}$Cd with a half-life over 2.9×10$^{20}$ years

## Palladium-103

Palladium-103 is a radioisotope of the element palladium that has uses in brachytherapy 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 days and decays by electron capture to an excited state of rhodium-103, which undergoes internal conversion to eject an electron. The resulting electron vacancy leads to emission of characteristic X-rays with 20–23 keV of energy.

## Palladium-107

Long-lived fission productsvte :
| Nuclide | t$_{1⁄2}$ | Yield | Q | βγ |
| | (Ma) | (%) | (keV) | |
| $^{99}$Tc | 0.211 | 6.1385 | 294 | β |
| $^{126}$Sn | 0.230 | 0.1084 | 4050 | βγ |
| $^{79}$Se | 0.327 | 0.0447 | 151 | β |
| $^{135}$Cs | 1.33 | 6.9110 | 269 | β |
| $^{93}$Zr | 1.53 | 5.4575 | 91 | βγ |
| $^{107}$Pd | 6.5 | 1.2499 | 33 | β |
| $^{129}$I | 16.14 | 0.8410 | 194 | βγ |
| ↑ Decay energy is split among β, neutrino, and γ if any. ↑ Per 65 thermal neutron fissions of $^{235}$U and 35 of $^{239}$Pu. ↑ Has decay energy 380 keV, but its decay product $^{126}$Sb has decay energy 3.67 MeV. ↑ Lower in thermal reactors because $^{135}$Xe, its predecessor, readily absorbs neutrons. |||||
Palladium-107 is the second-longest lived (half-life of 6.5 million years) 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 $^{107}$Ag, which is stable.
Its yield from thermal neutron fission of uranium-235 is 0.14% per fission, only 1/4 that of iodine-129, and only 1/40 those of $^{99}$Tc, $^{93}$Zr, and $^{135}$Cs. Yield from $^{233}$U is slightly lower, but yield from $^{239}$Pu is much higher, 3.2%. Fast fission or fission of some heavier actinides$^{[which?]}$ will produce palladium-107 at higher yields.
One source estimates that palladium produced from fission contains the isotopes $^{104}$Pd (16.9%),$^{105}$Pd (29.3%), $^{106}$Pd (21.3%), $^{107}$Pd (17%), $^{108}$Pd (11.7%) and $^{110}$Pd (3.8%). According to another source, the proportion of $^{107}$Pd is 9.2% for palladium from thermal neutron fission of $^{235}$U, 11.8% for $^{233}$U, and 20.4% for $^{239}$Pu (and the $^{239}$Pu yield of palladium is about 10 times that of $^{235}$U).
Because of this dilution and because $^{105}$Pd has 11 times the neutron absorption cross section, $^{107}$Pd 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.