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Standard atomic weight Ar°(Dy) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Naturally occurring dysprosium (66Dy) is composed of 7 stable isotopes, 156Dy, 158Dy, 160Dy, 161Dy, 162Dy, 163Dy and 164Dy, with 164Dy being the most abundant (28.18% natural abundance). Twenty-nine radioisotopes have been characterized, with the most stable being 154Dy with a half-life of 1.4 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 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 states, 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, and the primary mode after is beta decay. The primary decay products before 164Dy are terbium isotopes, and the primary products after are holmium isotopes. Dysprosium is the heaviest element to have isotopes that are predicted to be stable rather than observationally stable isotopes that are predicted to be radioactive.
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) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Excitation energy | Normal proportion | Range of variation | |||||||||||||||||
138Dy | 66 | 72 | 137.96249(64)# | 200# ms | 0+ | ||||||||||||||
139Dy | 66 | 73 | 138.95954(54)# | 600(200) ms | 7/2+# | ||||||||||||||
140Dy | 66 | 74 | 139.95401(54)# | 700# ms | β+ | 140Tb | 0+ | ||||||||||||
140mDy | 2166.1(5) keV | 7.0(5) μs | (8−) | ||||||||||||||||
141Dy | 66 | 75 | 140.95135(32)# | 0.9(2) s | β+ | 141Tb | (9/2−) | ||||||||||||
β+, p (rare) | 140Gd | ||||||||||||||||||
142Dy | 66 | 76 | 141.94637(39)# | 2.3(3) s | β+ (90(4)%) | 142Tb | 0+ | ||||||||||||
EC (10(4)%) | |||||||||||||||||||
β+, p (.06%) | 141Gd | ||||||||||||||||||
143Dy | 66 | 77 | 142.94383(21)# | 5.6(10) s | β+ | 143Tb | (1/2+) | ||||||||||||
β+, p (rare) | 142Gd | ||||||||||||||||||
143mDy | 310.7(6) keV | 3.0(3) s | (11/2−) | ||||||||||||||||
144Dy | 66 | 78 | 143.93925(3) | 9.1(4) s | β+ | 144Tb | 0+ | ||||||||||||
β+, p (rare) | 143Gd | ||||||||||||||||||
145Dy | 66 | 79 | 144.93743(5) | 9.5(10) s | β+ | 145Tb | (1/2+) | ||||||||||||
β+, p (rare) | 144Gd | ||||||||||||||||||
145mDy | 118.2(2) keV | 14.1(7) s | β+ | 145Tb | (11/2−) | ||||||||||||||
146Dy | 66 | 80 | 145.932845(29) | 33.2(7) s | β+ | 146Tb | 0+ | ||||||||||||
146mDy | 2935.7(6) keV | 150(20) ms | IT | 146Dy | (10+)# | ||||||||||||||
147Dy | 66 | 81 | 146.931092(21) | 40(10) s | β+ (99.95%) | 147Tb | 1/2+ | ||||||||||||
β+, p (.05%) | 146Tb | ||||||||||||||||||
147m1Dy | 750.5(4) keV | 55(1) s | β+ (65%) | 147Tb | 11/2− | ||||||||||||||
IT (35%) | 147Dy | ||||||||||||||||||
147m2Dy | 3407.2(8) keV | 0.40(1) μs | (27/2−) | ||||||||||||||||
148Dy | 66 | 82 | 147.927150(11) | 3.3(2) min | β+ | 148Tb | 0+ | ||||||||||||
149Dy | 66 | 83 | 148.927305(9) | 4.20(14) min | β+ | 149Tb | 7/2(−) | ||||||||||||
149mDy | 2661.1(4) keV | 490(15) ms | IT (99.3%) | 149Dy | (27/2−) | ||||||||||||||
β+ (.7%) | 149Tb | ||||||||||||||||||
150Dy | 66 | 84 | 149.925585(5) | 7.17(5) min | β+ (64%) | 150Tb | 0+ | ||||||||||||
α (36%) | 146Gd | ||||||||||||||||||
151Dy | 66 | 85 | 150.926185(4) | 17.9(3) min | β+ (94.4%) | 151Tb | 7/2(−) | ||||||||||||
α (5.6%) | 147Gd | ||||||||||||||||||
152Dy | 66 | 86 | 151.924718(6) | 2.38(2) h | EC (99.9%) | 152Tb | 0+ | ||||||||||||
α (.1%) | 148Gd | ||||||||||||||||||
153Dy | 66 | 87 | 152.925765(5) | 6.4(1) h | β+ (99.99%) | 153Tb | 7/2(−) | ||||||||||||
α (.00939%) | 149Gd | ||||||||||||||||||
154Dy | 66 | 88 | 153.924424(8) | 1.40(8)×106 y [5] | α | 150Gd | 0+ | ||||||||||||
155Dy | 66 | 89 | 154.925754(13) | 9.9(2) h | β+ | 155Tb | 3/2− | ||||||||||||
155mDy | 234.33(3) keV | 6(1) μs | 11/2− | ||||||||||||||||
156Dy | 66 | 90 | 155.924283(7) | Observationally Stable [n 8] | 0+ | 5.6(3)×10−4 | |||||||||||||
157Dy | 66 | 91 | 156.925466(7) | 8.14(4) h | β+ | 157Tb | 3/2− | ||||||||||||
157m1Dy | 161.99(3) keV | 1.3(2) μs | 9/2+ | ||||||||||||||||
157m2Dy | 199.38(7) keV | 21.6(16) ms | IT | 157Dy | 11/2− | ||||||||||||||
158Dy | 66 | 92 | 157.924409(4) | Observationally Stable [n 9] | 0+ | 9.5(3)×10−4 | |||||||||||||
159Dy | 66 | 93 | 158.9257392(29) | 144.4(2) d | EC | 159Tb | 3/2− | ||||||||||||
159mDy | 352.77(14) keV | 122(3) μs | 11/2− | ||||||||||||||||
160Dy | 66 | 94 | 159.9251975(27) | Observationally Stable [n 10] | 0+ | 0.02329(18) | |||||||||||||
161Dy | 66 | 95 | 160.9269334(27) | Observationally Stable [n 11] | 5/2+ | 0.18889(42) | |||||||||||||
162Dy | 66 | 96 | 161.9267984(27) | Observationally Stable [n 12] | 0+ | 0.25475(36) | |||||||||||||
163Dy | 66 | 97 | 162.9287312(27) | Stable [n 13] [6] | 5/2− | 0.24896(42) | |||||||||||||
164Dy [n 14] | 66 | 98 | 163.9291748(27) | Stable | 0+ | 0.28260(54) | |||||||||||||
165Dy | 66 | 99 | 164.9317033(27) | 2.334(1) h | β− | 165Ho | 7/2+ | ||||||||||||
165mDy | 108.160(3) keV | 1.257(6) min | IT (97.76%) | 165Dy | 1/2− | ||||||||||||||
β− (2.24%) | 165Ho | ||||||||||||||||||
166Dy | 66 | 100 | 165.9328067(28) | 81.6(1) h | β− | 166Ho | 0+ | ||||||||||||
167Dy | 66 | 101 | 166.93566(6) | 6.20(8) min | β− | 167Ho | (1/2−) | ||||||||||||
168Dy | 66 | 102 | 167.93713(15) | 8.7(3) min | β− | 168Ho | 0+ | ||||||||||||
169Dy | 66 | 103 | 168.94031(32) | 39(8) s | β− | 169Ho | (5/2−) | ||||||||||||
170Dy | 66 | 104 | 169.94239(21)# | 30# s | β− | 170Ho | 0+ | ||||||||||||
171Dy | 66 | 105 | 170.94620(32)# | 6# s | β− | 171Ho | 7/2−# | ||||||||||||
172Dy | 66 | 106 | 171.94876(43)# | 3# s | β− | 172Ho | 0+ | ||||||||||||
173Dy | 66 | 107 | 172.95300(54)# | 2# s | β− | 173Ho | 9/2+# | ||||||||||||
This table header & footer: |
EC: | Electron capture |
IT: | Isomeric transition |
p: | Proton emission |
The radioactive isotope 165Dy, with a half-life of 2.334 hours, has radiopharmaceutical uses in radiation synovectomy of the knee. It had been previously performed with colloidal-sized particles containing longer-lived isotopes such as 198Au and 90Y. The major problem with the usage of those isotopes was radiation leakage out of the knee. 165Dy, with its shorter half-life, is more suitable for the procedure as radiation leakage can only occur in its short half-life. [7]
Actinium (89Ac) has no stable isotopes and no characteristic terrestrial isotopic composition, thus a standard atomic weight cannot be given. There are 33 known isotopes, from 204Ac to 236Ac, and 7 isomers. Three isotopes are found in nature, 225Ac, 227Ac and 228Ac, as intermediate decay products of, respectively, 237Np, 235U, and 232Th. 228Ac and 225Ac are extremely rare, so almost all natural actinium is 227Ac.
Thallium (81Tl) has 41 isotopes with atomic masses that range from 176 to 216. 203Tl and 205Tl are the only stable isotopes and 204Tl is the most stable radioisotope with a half-life of 3.78 years. 207Tl, with a half-life of 4.77 minutes, has the longest half-life of naturally occurring Tl radioisotopes. All isotopes of thallium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
There are seven stable isotopes of mercury (80Hg) with 202Hg being the most abundant (29.86%). The longest-lived radioisotopes are 194Hg with a half-life of 444 years, and 203Hg with a half-life of 46.612 days. Most of the remaining 40 radioisotopes have half-lives that are less than a day. 199Hg and 201Hg are the most often studied NMR-active nuclei, having spin quantum numbers of 1/2 and 3/2 respectively. All isotopes of mercury are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. These isotopes are predicted to undergo either alpha decay or double beta decay.
Gold (79Au) has one stable isotope, 197Au, and 37 radioisotopes, with 195Au being the most stable with a half-life of 186 days. Gold is currently considered the heaviest monoisotopic element. Bismuth formerly held that distinction until alpha-decay of the 209Bi isotope was observed. All isotopes of gold are either radioactive or, in the case of 197Au, observationally stable, meaning that 197Au is predicted to be radioactive but no actual decay has been observed.
Naturally occurring platinum (78Pt) consists of five stable isotopes (192Pt, 194Pt, 195Pt, 196Pt, 198Pt) and one very long-lived (half-life 4.83×1011 years) radioisotope (190Pt). There are also 34 known synthetic radioisotopes, the longest-lived of which is 193Pt with a half-life of 50 years. All other isotopes have half-lives under a year, most under a day. All isotopes of platinum are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. Platinum-195 is the most abundant isotope.
There are two natural isotopes of iridium (77Ir), and 37 radioisotopes, the most stable radioisotope being 192Ir with a half-life of 73.83 days, and many nuclear isomers, the most stable of which is 192m2Ir with a half-life of 241 years. All other isomers have half-lives under a year, most under a day. All isotopes of iridium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
Naturally occurring tungsten (74W) consists of five isotopes. Four are considered stable (182W, 183W, 184W, and 186W) and one is slightly radioactive, 180W, with an extremely long half-life of 1.8 ± 0.2 exayears (1018 years). On average, two alpha decays of 180W occur per gram of natural tungsten per year, so for most practical purposes, 180W can be considered stable. Theoretically, all five can decay into isotopes of element 72 (hafnium) by alpha emission, but only 180W has been observed to do so. The other naturally occurring isotopes have not been observed to decay (they are observationally stable), and lower bounds for their half-lives have been established:
Natural hafnium (72Hf) consists of five observationally stable isotopes (176Hf, 177Hf, 178Hf, 179Hf, and 180Hf) and one very long-lived radioisotope, 174Hf, with a half-life of 7.0×1016 years. In addition, there are 34 known synthetic radioisotopes, the most stable of which is 182Hf with a half-life of 8.9×106 years. This extinct radionuclide is used in hafnium–tungsten dating to study the chronology of planetary differentiation.
Naturally occurring lutetium (71Lu) is composed of one stable isotope 175Lu (97.41% natural abundance) and one long-lived radioisotope, 176Lu with a half-life of 3.78 × 1010 years (2.59% natural abundance). Forty radioisotopes have been characterized, with the most stable, besides 176Lu, being 174Lu with a half-life of 3.31 years, and 173Lu with a half-life of 1.37 years. All of the remaining radioactive isotopes have half-lives that are less than 9 days, and the majority of these have half-lives that are less than half an hour. This element also has 18 meta states, with the most stable being 177mLu (t1/2 160.4 days), 174mLu (t1/2 142 days) and 178mLu (t1/2 23.1 minutes).
Naturally occurring ytterbium (70Yb) is composed of seven stable isotopes: 168Yb, 170Yb–174Yb, and 176Yb, with 174Yb being the most abundant. 30 radioisotopes have been characterized, with the most stable being 169Yb with a half-life of 32.014 days, 175Yb with a half-life of 4.185 days, and 166Yb with a half-life of 56.7 hours. All of the remaining radioactive isotopes have half-lives that are less than 2 hours, and the majority of these have half-lives that are less than 20 minutes. This element also has 18 meta states, with the most stable being 169mYb.
Naturally occurring erbium (68Er) is composed of 6 stable isotopes, with 166Er being the most abundant. 39 radioisotopes have been characterized with between 74 and 112 neutrons, or 142 to 180 nucleons, with the most stable being 169Er with a half-life of 9.4 days, 172Er with a half-life of 49.3 hours, 160Er with a half-life of 28.58 hours, 165Er with a half-life of 10.36 hours, and 171Er with a half-life of 7.516 hours. All of the remaining radioactive isotopes have half-lives that are less than 3.5 hours, and the majority of these have half-lives that are less than 4 minutes. This element also has numerous meta states, with the most stable being 167mEr.
Naturally occurring terbium (65Tb) is composed of one stable isotope, 159Tb. Thirty-seven radioisotopes have been characterized, with the most stable being 158Tb with a half-life of 180 years, 157Tb with a half-life of 71 years, and 160Tb with a half-life of 72.3 days. All of the remaining radioactive isotopes have half-lives that are less than 6.907 days, and the majority of these have half-lives that are less than 24 seconds. This element also has 27 meta states, with the most stable being 156m1Tb, 154m2Tb and 154m1Tb.
Naturally occurring gadolinium (64Gd) is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and 1 radioisotope, 152Gd, with 158Gd being the most abundant (24.84% natural abundance). The predicted double beta decay of 160Gd has never been observed; only a lower limit on its half-life of more than 1.3×1021 years has been set experimentally.
Naturally occurring cerium (58Ce) is composed of 4 stable isotopes: 136Ce, 138Ce, 140Ce, and 142Ce, with 140Ce being the most abundant and the only one theoretically stable; 136Ce, 138Ce, and 142Ce are predicted to undergo double beta decay but this process has never been observed. There are 35 radioisotopes that have been characterized, with the most stable being 144Ce, with a half-life of 284.893 days; 139Ce, with a half-life of 137.640 days and 141Ce, with a half-life of 32.501 days. All of the remaining radioactive isotopes have half-lives that are less than 4 days and the majority of these have half-lives that are less than 10 minutes. This element also has 10 meta states.
Naturally occurring barium (56Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001. This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×1021 years (about 1011 times the age of the universe).
Indium (49In) consists of two primordial nuclides, with the most common (~ 95.7%) nuclide (115In) being measurably though weakly radioactive. Its spin-forbidden decay has a half-life of 4.41×1014 years, much longer than the currently accepted age of the Universe.
Arsenic (33As) has 33 known isotopes and at least 10 isomers. Only one of these isotopes, 75As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is 73As with a half-life of 80 days. Arsenic has been proposed as a "salting" material for nuclear weapons. A jacket of 75As, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope 76As with a half-life of 1.0778 days and produce approximately 1.13 MeV gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several hours. Such a weapon is not known to have ever been built, tested, or used.
Naturally occurring zinc (30Zn) is composed of the 5 stable isotopes 64Zn, 66Zn, 67Zn, 68Zn, and 70Zn with 64Zn being the most abundant. Twenty-five radioisotopes have been characterised with the most abundant and stable being 65Zn with a half-life of 244.26 days, and 72Zn with a half-life of 46.5 hours. All of the remaining radioactive isotopes have half-lives that are less than 14 hours and the majority of these have half-lives that are less than 1 second. This element also has 10 meta states.
Naturally occurring cobalt (27Co) consists of a single stable isotope, 59Co. Twenty-eight radioisotopes have been characterized; the most stable are 60Co with a half-life of 5.2714 years, 57Co, 56Co, and 58Co. All other isotopes have half-lives of less than 18 hours and most of these have half-lives of less than 1 second. This element also has 11 meta states, all of which have half-lives of less than 15 minutes.
Naturally occurring chromium (24Cr) is composed of four stable isotopes; 50Cr, 52Cr, 53Cr, and 54Cr with 52Cr being the most abundant (83.789% natural abundance). 50Cr is suspected of decaying by β+β+ to 50Ti with a half-life of (more than) 1.8×1017 years. Twenty-two radioisotopes, all of which are entirely synthetic, have been characterized, the most stable being 51Cr with a half-life of 27.7 days. All of the remaining radioactive isotopes have half-lives that are less than 24 hours and the majority of these have half-lives that are less than 1 minute. This element also has two meta states, 45mCr, the more stable one, and 59mCr, the least stable isotope or isomer.