Naturally occurring

dysprosium Dysprosium is the chemical element with the symbol Dy and atomic number 66. It is a rare-earth element in the lanthanide series with a metallic silver luster. Dysprosium is never found in nature as a free element, though, like other lanthanides, ...

(₆₆Dy) is composed of 7 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 numb ...

s, ¹⁵⁶Dy, ¹⁵⁸Dy, ¹⁶⁰Dy, ¹⁶¹Dy, ¹⁶²Dy, ¹⁶³Dy and ¹⁶⁴Dy, with ¹⁶⁴Dy being the most abundant (28.18%

natural abundance In physics, natural abundance (NA) refers to the abundance of isotopes of a chemical element as naturally found on a planet. The relative atomic mass (a weighted average, weighted by mole-fraction abundance figures) of these isotopes is the atomi ...

). Twenty-nine

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 have been characterized, with the most stable being ¹⁵⁴Dy 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 at ...

of 3.0 million years, ¹⁵⁹Dy with a half-life of 144.4 days, and ¹⁶⁶Dy with a half-life of 81.6 hours. All of the remaining

radioactive 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 consi ...

isotopes have half-lives that are less than 10 hours, and the majority of these have half-lives that are less than 30 seconds. This element also has 12

meta state A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy higher energy levels than in the ground state of the same nucleus. "Metastable" describes nuclei whose excited states have ...

s, with the most stable being ^165mDy (half-life 1.257 minutes), ^147mDy (half-life 55.7 seconds) and ^145mDy (half-life 13.6 seconds). The primary decay mode before the most abundant stable isotope, ¹⁶⁴Dy, 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. Thi ...

, 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 ...

. The primary decay products before ¹⁶⁴Dy are

terbium Terbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable, and ductile. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with w ...

isotopes, and the primary products after are

holmium Holmium is a chemical element with the symbol Ho and atomic number 67. It is a rare-earth element and the eleventh member of the lanthanide series. It is a relatively soft, silvery, fairly corrosion-resistant and malleable metal. Like a lot of oth ...

isotopes. Dysprosium is the heaviest element to have isotopes that are predicted to be stable rather than

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 ...

isotopes that are predicted to be radioactive.

List of isotopes

, - , ¹³⁸Dy , style="text-align:right" , 66 , style="text-align:right" , 72 , 137.96249(64)# , 200# ms , , , 0+ , , , - , ¹³⁹Dy , style="text-align:right" , 66 , style="text-align:right" , 73 , 138.95954(54)# , 600(200) ms , , , 7/2+# , , , - , ¹⁴⁰Dy , style="text-align:right" , 66 , style="text-align:right" , 74 , 139.95401(54)# , 700# ms , β⁺ , ¹⁴⁰Tb , 0+ , , , - , style="text-indent:1em" , ^140mDy , colspan="3" style="text-indent:2em" , 2166.1(5) keV , 7.0(5) μs , , , (8−) , , , - , rowspan=2, ¹⁴¹Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 75 , rowspan=2, 140.95135(32)# , rowspan=2, 0.9(2) s , β⁺ , ¹⁴¹Tb , rowspan=2, (9/2−) , rowspan=2, , rowspan=2, , - , β⁺, p (rare) , ¹⁴⁰Gd , - , rowspan=2, ¹⁴²Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 76 , rowspan=2, 141.94637(39)# , rowspan=2, 2.3(3) s , β⁺ (99.94%) , ¹⁴²Tb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p (.06%) , ¹⁴¹Gd , - , rowspan=2, ¹⁴³Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 77 , rowspan=2, 142.94383(21)# , rowspan=2, 5.6(10) s , β⁺ , ¹⁴³Tb , rowspan=2, (1/2+) , rowspan=2, , rowspan=2, , - , β⁺, p (rare) , ¹⁴²Gd , - , style="text-indent:1em" , ^143mDy , colspan="3" style="text-indent:2em" , 310.7(6) keV , 3.0(3) s , , , (11/2−) , , , - , rowspan=2, ¹⁴⁴Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 78 , rowspan=2, 143.93925(3) , rowspan=2, 9.1(4) s , β⁺ , ¹⁴⁴Tb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p (rare) , ¹⁴³Gd , - , rowspan=2, ¹⁴⁵Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 79 , rowspan=2, 144.93743(5) , rowspan=2, 9.5(10) s , β⁺ , ¹⁴⁵Tb , rowspan=2, (1/2+) , rowspan=2, , rowspan=2, , - , β⁺, p (rare) , ¹⁴⁴Gd , - , style="text-indent:1em" , ^145mDy , colspan="3" style="text-indent:2em" , 118.2(2) keV , 14.1(7) s , β⁺ , ¹⁴⁵Tb , (11/2−) , , , - , ¹⁴⁶Dy , style="text-align:right" , 66 , style="text-align:right" , 80 , 145.932845(29) , 33.2(7) s , β⁺ , ¹⁴⁶Tb , 0+ , , , - , style="text-indent:1em" , ^146mDy , colspan="3" style="text-indent:2em" , 2935.7(6) keV , 150(20) ms , IT , ¹⁴⁶Dy , (10+)# , , , - , rowspan=2, ¹⁴⁷Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 81 , rowspan=2, 146.931092(21) , rowspan=2, 40(10) s , β⁺ (99.95%) , ¹⁴⁷Tb , rowspan=2, 1/2+ , rowspan=2, , rowspan=2, , - , β⁺, p (.05%) , ¹⁴⁶Tb , - , rowspan=2 style="text-indent:1em" , ^147m1Dy , rowspan=2 colspan="3" style="text-indent:2em" , 750.5(4) keV , rowspan=2, 55(1) s , β⁺ (65%) , ¹⁴⁷Tb , rowspan=2, 11/2− , rowspan=2, , rowspan=2, , - , IT (35%) , ¹⁴⁷Dy , - , style="text-indent:1em" , ^147m2Dy , colspan="3" style="text-indent:2em" , 3407.2(8) keV , 0.40(1) μs , , , (27/2−) , , , - , ¹⁴⁸Dy , style="text-align:right" , 66 , style="text-align:right" , 82 , 147.927150(11) , 3.3(2) min , β⁺ , ¹⁴⁸Tb , 0+ , , , - , ¹⁴⁹Dy , style="text-align:right" , 66 , style="text-align:right" , 83 , 148.927305(9) , 4.20(14) min , β⁺ , ¹⁴⁹Tb , 7/2(−) , , , - , rowspan=2 style="text-indent:1em" , ^149mDy , rowspan=2 colspan="3" style="text-indent:2em" , 2661.1(4) keV , rowspan=2, 490(15) ms , IT (99.3%) , ¹⁴⁹Dy , rowspan=2, (27/2−) , rowspan=2, , rowspan=2, , - , β⁺ (.7%) , ¹⁴⁹Tb , - , rowspan=2, ¹⁵⁰Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 84 , rowspan=2, 149.925585(5) , rowspan=2, 7.17(5) min , β⁺ (64%) , ¹⁵⁰Tb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , α (36%) , ¹⁴⁶Gd , - , rowspan=2, ¹⁵¹Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 85 , rowspan=2, 150.926185(4) , rowspan=2, 17.9(3) min , β⁺ (94.4%) , ¹⁵¹Tb , rowspan=2, 7/2(−) , rowspan=2, , rowspan=2, , - , α (5.6%) , ¹⁴⁷Gd , - , rowspan=2, ¹⁵²Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 86 , rowspan=2, 151.924718(6) , rowspan=2, 2.38(2) h , EC (99.9%) , ¹⁵²Tb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , α (.1%) , ¹⁴⁸Gd , - , rowspan=2, ¹⁵³Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 87 , rowspan=2, 152.925765(5) , rowspan=2, 6.4(1) h , β⁺ (99.99%) , ¹⁵³Tb , rowspan=2, 7/2(−) , rowspan=2, , rowspan=2, , - , α (.00939%) , ¹⁴⁹Gd , - , rowspan=2, ¹⁵⁴Dy , rowspan=2 style="text-align:right" , 66 , rowspan=2 style="text-align:right" , 88 , rowspan=2, 153.924424(8) , rowspan=2, 3.0(15)×10⁶ y , α , ¹⁵⁰Gd , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺β⁺ (rare) , ¹⁵⁴Gd , - , ¹⁵⁵Dy , style="text-align:right" , 66 , style="text-align:right" , 89 , 154.925754(13) , 9.9(2) h , β⁺ , ¹⁵⁵Tb , 3/2− , , , - , style="text-indent:1em" , ^155mDy , colspan="3" style="text-indent:2em" , 234.33(3) keV , 6(1) μs , , , 11/2− , , , - , ¹⁵⁶Dy , style="text-align:right" , 66 , style="text-align:right" , 90 , 155.924283(7) , 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 undergo α decay to ''¹⁵²Gd'' or β⁺β⁺ decay to ¹⁵⁶Gd with a

over 10¹⁸ years , 0+ , 5.6(3)×10⁻⁴ , , - , ¹⁵⁷Dy , style="text-align:right" , 66 , style="text-align:right" , 91 , 156.925466(7) , 8.14(4) h , β⁺ , ¹⁵⁷Tb , 3/2− , , , - , style="text-indent:1em" , ^157m1Dy , colspan="3" style="text-indent:2em" , 161.99(3) keV , 1.3(2) μs , , , 9/2+ , , , - , style="text-indent:1em" , ^157m2Dy , colspan="3" style="text-indent:2em" , 199.38(7) keV , 21.6(16) ms , IT , ¹⁵⁷Dy , 11/2− , , , - , ¹⁵⁸Dy , style="text-align:right" , 66 , style="text-align:right" , 92 , 157.924409(4) , colspan=3 align=center, Observationally StableBelieved to undergo α decay to ¹⁵⁴Gd or β⁺β⁺ decay to ¹⁵⁸Gd , 0+ , 9.5(3)×10⁻⁴ , , - , ¹⁵⁹Dy , style="text-align:right" , 66 , style="text-align:right" , 93 , 158.9257392(29) , 144.4(2) d , EC , ¹⁵⁹Tb , 3/2− , , , - , style="text-indent:1em" , ^159mDy , colspan="3" style="text-indent:2em" , 352.77(14) keV , 122(3) μs , , , 11/2− , , , - , ¹⁶⁰Dy , style="text-align:right" , 66 , style="text-align:right" , 94 , 159.9251975(27) , colspan=3 align=center, Observationally StableBelieved to undergo α decay to ¹⁵⁶Gd , 0+ , 0.02329(18) , , - , ¹⁶¹Dy , style="text-align:right" , 66 , style="text-align:right" , 95 , 160.9269334(27) , colspan=3 align=center, Observationally StableBelieved to undergo α decay to ¹⁵⁷Gd , 5/2+ , 0.18889(42) , , - , ¹⁶²Dy , style="text-align:right" , 66 , style="text-align:right" , 96 , 161.9267984(27) , colspan=3 align=center, Observationally StableBelieved to undergo α decay to ¹⁵⁸Gd , 0+ , 0.25475(36) , , - , ¹⁶³Dy , style="text-align:right" , 66 , style="text-align:right" , 97 , 162.9287312(27) , colspan=3 align=center, StableTheoretically capable of spontaneous fissionCan undergo bound-state β⁻ decay to ¹⁶³Ho with a half-life of 47 days when fully

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

ized , 5/2− , 0.24896(42) , , - , ¹⁶⁴Dy , style="text-align:right" , 66 , style="text-align:right" , 98 , 163.9291748(27) , colspan=3 align=center, Stable , 0+ , 0.28260(54) , , - , ¹⁶⁵Dy , style="text-align:right" , 66 , style="text-align:right" , 99 , 164.9317033(27) , 2.334(1) h , β⁻ , ¹⁶⁵Ho , 7/2+ , , , - , rowspan=2 style="text-indent:1em" , ^165mDy , rowspan=2 colspan="3" style="text-indent:2em" , 108.160(3) keV , rowspan=2, 1.257(6) min , IT (97.76%) , ¹⁶⁵Dy , rowspan=2, 1/2− , rowspan=2, , rowspan=2, , - , β⁻ (2.24%) , ¹⁶⁵Ho , - , ¹⁶⁶Dy , style="text-align:right" , 66 , style="text-align:right" , 100 , 165.9328067(28) , 81.6(1) h , β⁻ , ¹⁶⁶Ho , 0+ , , , - , ¹⁶⁷Dy , style="text-align:right" , 66 , style="text-align:right" , 101 , 166.93566(6) , 6.20(8) min , β⁻ , ¹⁶⁷Ho , (1/2−) , , , - , ¹⁶⁸Dy , style="text-align:right" , 66 , style="text-align:right" , 102 , 167.93713(15) , 8.7(3) min , β⁻ , ¹⁶⁸Ho , 0+ , , , - , ¹⁶⁹Dy , style="text-align:right" , 66 , style="text-align:right" , 103 , 168.94031(32) , 39(8) s , β⁻ , ¹⁶⁹Ho , (5/2−) , , , - , ¹⁷⁰Dy , style="text-align:right" , 66 , style="text-align:right" , 104 , 169.94239(21)# , 30# s , β⁻ , ¹⁷⁰Ho , 0+ , , , - , ¹⁷¹Dy , style="text-align:right" , 66 , style="text-align:right" , 105 , 170.94620(32)# , 6# s , β⁻ , ¹⁷¹Ho , 7/2−# , , , - , ¹⁷²Dy , style="text-align:right" , 66 , style="text-align:right" , 106 , 171.94876(43)# , 3# s , β⁻ , ¹⁷²Ho , 0+ , , , - , ¹⁷³Dy , style="text-align:right" , 66 , style="text-align:right" , 107 , 172.95300(54)# , 2# s , β⁻ , ¹⁷³Ho , 9/2+# , , * Geologically exceptional samples are found associated with the

Oklo Oklo is a region near the town of Franceville, in the Haut-Ogooué province of the Central African country of Gabon. Several natural nuclear fission reactors were discovered in the uranium mines in the region in 1972. History Gabon was a Fren ...

natural nuclear fission reactor A natural nuclear fission reactor is a uranium deposit where self-sustaining nuclear chain reactions occur. The conditions under which a natural nuclear reactor could exist had been predicted in 1956 by Japanese American chemist Paul Kuroda. ...

, in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.

Dysprosium-165

The radioactive isotope ¹⁶⁵Dy, with a half life of 2.334 hours, has

radiopharmaceutical Radiopharmaceuticals, or medicinal radiocompounds, are a group of pharmaceutical drugs containing radioactive isotopes. Radiopharmaceuticals can be used as diagnostic and therapeutic agents. Radiopharmaceuticals emit radiation themselves, which ...

uses.

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Navbox element isotopes Dysprosium

Dysprosium Dysprosium is the chemical element with the symbol Dy and atomic number 66. It is a rare-earth element in the lanthanide series with a metallic silver luster. Dysprosium is never found in nature as a free element, though, like other lanthanides, ...