Naturally occurring

palladium Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...

(₄₆Pd) is composed of six stable

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers ( mass numbers ...

s, ¹⁰²Pd, ¹⁰⁴Pd, ¹⁰⁵Pd, ¹⁰⁶Pd, ¹⁰⁸Pd, and ¹¹⁰Pd, although ¹⁰²Pd and ¹¹⁰Pd are theoretically unstable. The most stable

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

s are ¹⁰⁷Pd with a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ato ...

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 weight Relative atomic mass (symbol: ''A''; sometimes abbreviated RAM or r.a.m.), also known by the deprecated synonym atomic weight, is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a giv ...

s 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 Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consid ...

before the most abundant stable isotope, ¹⁰⁶Pd, is

electron capture Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. Th ...

and the primary mode after is

beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For e ...

. The primary

decay product In nuclear physics, a decay product (also known as a daughter product, daughter isotope, radio-daughter, or daughter nuclide) is the remaining nuclide left over from radioactive decay. Radioactive decay often proceeds via a sequence of steps (de ...

before ¹⁰⁶Pd is

rhodium Rhodium is a chemical element with the symbol Rh and atomic number 45. It is a very rare, silvery-white, hard, corrosion-resistant transition metal. It is a noble metal and a member of the platinum group. It has only one naturally occurring isoto ...

and the primary product after is

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical co ...

Radiogenic A radiogenic nuclide is a nuclide that is produced by a process of radioactive decay. It may itself be radioactive (a radionuclide) or stable (a stable nuclide). Radiogenic nuclides (more commonly referred to as radiogenic isotopes) form some of ...

¹⁰⁷Ag is a decay product of ¹⁰⁷Pd 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. ¹⁰⁷Pd versus Ag correlations observed in bodies, which have clearly been melted since accretion of the

Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...

, must reflect the presence of short-lived nuclides in the early Solar System.

List of isotopes

, - , ⁹¹Pd , style="text-align:right" , 46 , style="text-align:right" , 45 , 90.94911(61)# , 10# ms 1.5 µs, β⁺ , ⁹¹Rh , 7/2+# , , , - , ⁹²Pd , style="text-align:right" , 46 , style="text-align:right" , 46 , 91.94042(54)# , 1.1(3) s .7(+4−2) s, β⁺ , ⁹²Rh , 0+ , , , - , ⁹³Pd , style="text-align:right" , 46 , style="text-align:right" , 47 , 92.93591(43)# , 1.07(12) s , β⁺ , ⁹³Rh , (9/2+) , , , - , style="text-indent:1em" , ^93mPd , colspan="3" style="text-indent:2em" , 0+X keV , 9.3(+25−17) s , , , , , , - , ⁹⁴Pd , style="text-align:right" , 46 , style="text-align:right" , 48 , 93.92877(43)# , 9.0(5) s , β⁺ , ⁹⁴Rh , 0+ , , , - , style="text-indent:1em" , ^94mPd , colspan="3" style="text-indent:2em" , 4884.4(5) keV , 530(10) ns , , , (14+) , , , - , ⁹⁵Pd , style="text-align:right" , 46 , style="text-align:right" , 49 , 94.92469(43)# , 10# s , β⁺ , ⁹⁵Rh , 9/2+# , , , - , rowspan=3 style="text-indent:1em" , ^95mPd , rowspan=3 colspan="3" style="text-indent:2em" , 1860(500)# keV , rowspan=3, 13.3(3) s , β⁺ (94.1%) , ⁹⁵Rh , rowspan=3, (21/2+) , rowspan=3, , rowspan=3, , - , IT (5%) , ⁹⁵Pd , - , β⁺, p (.9%) , ⁹⁴Ru , - , ⁹⁶Pd , style="text-align:right" , 46 , style="text-align:right" , 50 , 95.91816(16) , 122(2) s , β⁺ , ⁹⁶Rh , 0+ , , , - , style="text-indent:1em" , ^96mPd , colspan="3" style="text-indent:2em" , 2530.8(1) keV , 1.81(1) µs , , , 8+ , , , - , ⁹⁷Pd , style="text-align:right" , 46 , style="text-align:right" , 51 , 96.91648(32) , 3.10(9) min , β⁺ , ⁹⁷Rh , 5/2+# , , , - , ⁹⁸Pd , style="text-align:right" , 46 , style="text-align:right" , 52 , 97.912721(23) , 17.7(3) min , β⁺ , ⁹⁸Rh , 0+ , , , - , ⁹⁹Pd , style="text-align:right" , 46 , style="text-align:right" , 53 , 98.911768(16) , 21.4(2) min , β⁺ , ⁹⁹Rh , (5/2)+ , , , - , ¹⁰⁰Pd , style="text-align:right" , 46 , style="text-align:right" , 54 , 99.908506(12) , 3.63(9) d , EC , ¹⁰⁰Rh , 0+ , , , - , ¹⁰¹Pd , style="text-align:right" , 46 , style="text-align:right" , 55 , 100.908289(19) , 8.47(6) h , β⁺ , ¹⁰¹Rh , 5/2+ , , , - , ¹⁰²Pd , style="text-align:right" , 46 , style="text-align:right" , 56 , 101.905609(3) , colspan=3 align=center,

Observationally Stable Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes. Th ...

Believed to decay by β⁺β⁺ to ¹⁰²Ru , 0+ , 0.0102(1) , , - , ¹⁰³PdUsed in medicine , style="text-align:right" , 46 , style="text-align:right" , 57 , 102.906087(3) , 16.991(19) d , EC , ¹⁰³Rh , 5/2+ , , , - , style="text-indent:1em" , ^103mPd , colspan="3" style="text-indent:2em" , 784.79(10) keV , 25(2) ns , , , 11/2− , , , - , ¹⁰⁴Pd , style="text-align:right" , 46 , style="text-align:right" , 58 , 103.904036(4) , colspan=3 align=center, StableTheoretically capable of

spontaneous fission Spontaneous fission (SF) is a form of radioactive decay that is found only in very heavy chemical elements. The nuclear binding energy of the elements reaches its maximum at an atomic mass number of about 56 (e.g., iron-56); spontaneous breakdow ...

, 0+ , 0.1114(8) , , - , ¹⁰⁵Pd

Fission product Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the release ...

, style="text-align:right" , 46 , style="text-align:right" , 59 , 104.905085(4) , colspan=3 align=center, Stable , 5/2+ , 0.2233(8) , , - , ¹⁰⁶Pd , style="text-align:right" , 46 , style="text-align:right" , 60 , 105.903486(4) , colspan=3 align=center, Stable , 0+ , 0.2733(3) , , - , ¹⁰⁷Pd

Long-lived fission product Long-lived fission products (LLFPs) are radioactive materials with a long half-life (more than 200,000 years) produced by nuclear fission of uranium and plutonium. Because of their persistent radiotoxicity it is necessary to isolate them from man ...

, style="text-align:right" , 46 , style="text-align:right" , 61 , 106.905133(4) , 6.5(3)×10⁶ y , β⁻ , ¹⁰⁷Ag , 5/2+ , trace Cosmogenic nuclide, also found as nuclear contamination , , - , style="text-indent:1em" , ^107m1Pd , colspan="3" style="text-indent:2em" , 115.74(12) keV , 0.85(10) µs , , , 1/2+ , , , - , style="text-indent:1em" , ^107m2Pd , colspan="3" style="text-indent:2em" , 214.6(3) keV , 21.3(5) s , IT , ¹⁰⁷Pd , 11/2− , , , - , ¹⁰⁸Pd , style="text-align:right" , 46 , style="text-align:right" , 62 , 107.903892(4) , colspan=3 align=center, Stable , 0+ , 0.2646(9) , , - , ¹⁰⁹Pd , style="text-align:right" , 46 , style="text-align:right" , 63 , 108.905950(4) , 13.7012(24) h , β⁻ , ^109mAg , 5/2+ , , , - , style="text-indent:1em" , ^109m1Pd , colspan="3" style="text-indent:2em" , 113.400(10) keV , 380(50) ns , , , 1/2+ , , , - , style="text-indent:1em" , ^109m2Pd , colspan="3" style="text-indent:2em" , 188.990(10) keV , 4.696(3) min , IT , ¹⁰⁹Pd , 11/2− , , , - , ¹¹⁰Pd , style="text-align:right" , 46 , style="text-align:right" , 64 , 109.905153(12) , colspan=3 align=center, Observationally StableBelieved to decay by β⁻β⁻ to ¹¹⁰Cd with a

over 6×10¹⁷ years , 0+ , 0.1172(9) , , - , ¹¹¹Pd , style="text-align:right" , 46 , style="text-align:right" , 65 , 110.907671(12) , 23.4(2) min , β⁻ , ^111mAg , 5/2+ , , , - , rowspan=2 style="text-indent:1em" , ^111mPd , rowspan=2 colspan="3" style="text-indent:2em" , 172.18(8) keV , rowspan=2, 5.5(1) h , IT , ¹¹¹Pd , rowspan=2, 11/2− , rowspan=2, , rowspan=2, , - , β⁻ , ^111mAg , - , ¹¹²Pd , style="text-align:right" , 46 , style="text-align:right" , 66 , 111.907314(19) , 21.03(5) h , β⁻ , ¹¹²Ag , 0+ , , , - , ¹¹³Pd , style="text-align:right" , 46 , style="text-align:right" , 67 , 112.91015(4) , 93(5) s , β⁻ , ^113mAg , (5/2+) , , , - , style="text-indent:1em" , ^113mPd , colspan="3" style="text-indent:2em" , 81.1(3) keV , 0.3(1) s , IT , ¹¹³Pd , (9/2−) , , , - , ¹¹⁴Pd , style="text-align:right" , 46 , style="text-align:right" , 68 , 113.910363(25) , 2.42(6) min , β⁻ , ¹¹⁴Ag , 0+ , , , - , ¹¹⁵Pd , style="text-align:right" , 46 , style="text-align:right" , 69 , 114.91368(7) , 25(2) s , β⁻ , ^115mAg , (5/2+)# , , , - , rowspan=2 style="text-indent:1em" , ^115mPd , rowspan=2 colspan="3" style="text-indent:2em" , 89.18(25) keV , rowspan=2, 50(3) s , β⁻ (92%) , ¹¹⁵Ag , rowspan=2, (11/2−)# , rowspan=2, , rowspan=2, , - , IT (8%) , ¹¹⁵Pd , - , ¹¹⁶Pd , style="text-align:right" , 46 , style="text-align:right" , 70 , 115.91416(6) , 11.8(4) s , β⁻ , ¹¹⁶Ag , 0+ , , , - , ¹¹⁷Pd , style="text-align:right" , 46 , style="text-align:right" , 71 , 116.91784(6) , 4.3(3) s , β⁻ , ^117mAg , (5/2+) , , , - , style="text-indent:1em" , ^117mPd , colspan="3" style="text-indent:2em" , 203.2(3) keV , 19.1(7) ms , IT , ¹¹⁷Pd , (11/2−)# , , , - , ¹¹⁸Pd , style="text-align:right" , 46 , style="text-align:right" , 72 , 117.91898(23) , 1.9(1) s , β⁻ , ¹¹⁸Ag , 0+ , , , - , ¹¹⁹Pd , style="text-align:right" , 46 , style="text-align:right" , 73 , 118.92311(32)# , 0.92(13) s , β⁻ , ¹¹⁹Ag , , , , - , ¹²⁰Pd , style="text-align:right" , 46 , style="text-align:right" , 74 , 119.92469(13) , 0.5(1) s , β⁻ , ¹²⁰Ag , 0+ , , , - , ¹²¹Pd , style="text-align:right" , 46 , style="text-align:right" , 75 , 120.92887(54)# , 285 ms , β⁻ , ¹²¹Ag , , , , - , ¹²²Pd , style="text-align:right" , 46 , style="text-align:right" , 76 , 121.93055(43)# , 175 ms 300 ns, β⁻ , ¹²²Ag , 0+ , , , - , ¹²³Pd , style="text-align:right" , 46 , style="text-align:right" , 77 , 122.93493(64)# , 108 ms , β⁻ , ¹²³Ag , , , , - , ¹²⁴Pd , style="text-align:right" , 46 , style="text-align:right" , 78 , 123.93688(54)# , 38 ms , β⁻ , ¹²⁴Ag , 0+ , , , - , ¹²⁵Pd , style="text-align:right" , 46 , style="text-align:right" , 79 , , 57 ms , β⁻ , ¹²⁵Ag , , , , - , ¹²⁶Pd , style="text-align:right" , 46 , style="text-align:right" , 80 , , 48.6 ms , β⁻ , ¹²⁶Ag , 0+ , , , - , style="text-indent:1em" , ^126m1Pd , colspan="3" style="text-indent:2em" , 2023 keV , 330 ns , IT , ¹²⁶Pd , 5− , , , - , style="text-indent:1em" , ^126m2Pd , colspan="3" style="text-indent:2em" , 2110 keV , 440 ns , IT , ^126m1Pd , 7− , , , - , ¹²⁷Pd , style="text-align:right" , 46 , style="text-align:right" , 81 , , 38 ms , β⁻ , ¹²⁷Ag , , , , - , ¹²⁸Pd , style="text-align:right" , 46 , style="text-align:right" , 82 , , 35 ms , β⁻ , ¹²⁸Ag , 0+ , , , - , style="text-indent:1em" , ^128mPd , colspan="3" style="text-indent:2em" , 2151 keV , 5.8 µs , IT , ¹²⁸Pd , 8+ , , , - , ¹²⁹Pd , style="text-align:right" , 46 , style="text-align:right" , 83 , , 31 ms , β⁻ , ¹²⁹Ag , , ,

Palladium-103

Palladium-103 is a

of the element

that has uses in

radiation therapy Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radi ...

for

prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that sur ...

and

uveal melanoma Uveal melanoma is a type of eye cancer in the uvea of the eye. It is traditionally classed as originating in the iris, choroid, and ciliary body, but can also be divided into class I (low metastatic risk) and class II (high metastatic risk). Symp ...

. Palladium-103 may be created from palladium-102 or from rhodium-103 using a

cyclotron A cyclotron is a type of particle accelerator invented by Ernest O. Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: Jan ...

. Palladium-103 has a

of 16.99 days and decays by

to rhodium-103, emitting characteristic

x-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30 ...

s with 21

keV Kev can refer to: Given name * Kev Adams, French comedian, actor, screenwriter and film producer born Kevin Smadja in 1991 * Kevin Kev Carmody (born 1946), Indigenous Australian singer-songwriter * Kev Coghlan (born 1988), Scottish Grand Prix moto ...

energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat ...

Palladium-107

Palladium-107 is the second-longest lived (

of 6.5 million years) and least radioactive (

decay energy The decay energy is the energy change of a nucleus having undergone a radioactive decay. Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting ionizing particles and radiation. This decay, or loss of energ ...

only 33

specific activity Specific activity is the activity per unit mass of a radionuclide and is a physical property of that radionuclide. Activity is a quantity (for which the SI unit is the becquerel) related to radioactivity, and is defined as the number of radi ...

5 Ci/g) of the 7 long-lived

fission products Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the release ...

. It undergoes pure

(without

gamma radiation A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically sh ...

) to ¹⁰⁷Ag, which is stable. Its yield from

thermal neutron The neutron detection temperature, also called the neutron energy, indicates a free neutron's kinetic energy, usually given in electron volts. The term ''temperature'' is used, since hot, thermal and cold neutrons are moderated in a medium with ...

fission of

uranium-235 Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists ...

is 0.1629% per fission, only 1/4 that of

iodine-129 Iodine-129 (129I) is a long-lived radioisotope of iodine which occurs naturally, but also is of special interest in the monitoring and effects of man-made nuclear fission products, where it serves as both tracer and potential radiological contami ...

, 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 Fast fission is fission that occurs when a heavy atom absorbs a high-energy neutron, called a fast neutron, and splits. Most fissionable materials need thermal neutrons, which move more slowly. Fast reactors vs. thermal reactors Fast neutron reac ...

or fission of some heavier

actinides The actinide () or actinoid () series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The actinide series derives its name from the first element in the series, actinium. The inform ...

^{'' hich?'} will produce palladium-107 at higher yields. One source 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 Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus. Since neutrons have no electric charge, they can enter a nucleus more easily than positively charged protons, ...

cross section Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture & engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **Abs ...

, ¹⁰⁷Pd is not amenable to disposal by

nuclear transmutation Nuclear transmutation is the conversion of one chemical element or an isotope into another chemical element. Nuclear transmutation occurs in any process where the number of protons or neutrons in the nucleus of an atom is changed. A transmut ...

. However, as a

noble metal A noble metal is ordinarily regarded as a metallic chemical element that is generally resistant to corrosion and is usually found in nature in its raw form. Gold, platinum, and the other platinum group metals (ruthenium, rhodium, palladium, o ...

, palladium is not as mobile in the environment as iodine or technetium.

References

Patent application for Palladium-103 implantable radiation-delivery device
(accessed 12/7/05) * Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Navbox element isotopes Palladium

Palladium Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...