Isotopes of hafnium
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Standard atomic weight Ar°(Hf) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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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 3.8×1016 years.[2] The next most stable radioisotope is 182Hf with a half-life of 8.90 million years, an extinct radionuclide used in hafnium–tungsten dating to study the chronology of planetary differentiation.[6]
Other isotopes have been synthesized running from 153Hf to 192Hf, but none of the 33 others has a half-life over 1.87 years, and most have half-lives under five minutes. There are also at least 41 nuclear isomers, the most stable of which is 178m2Hf with a half-life of 31 years. All isotopes of hafnium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
List of isotopes
[edit]
Nuclide [n 1] |
Z | N | Isotopic mass (Da)[7] [n 2][n 3] |
Half-life[1] [n 4][n 5] |
Decay mode[1] [n 6] |
Daughter isotope [n 7] |
Spin and parity[1] [n 8][n 5] |
Natural abundance (mole fraction) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Excitation energy[n 5] | Normal proportion[1] | Range of variation | |||||||||||||||||
153Hf | 72 | 81 | 152.97069(32)# | 400# ms [>200 ns] |
1/2+# | ||||||||||||||
154Hf | 72 | 82 | 153.96486(32)# | 2(1) s | β+ | 154Lu | 0+ | ||||||||||||
α (rare) | 150Yb | ||||||||||||||||||
154mHf | 2721(50)# keV | 9(4) μs | IT | 154Hf | (10+) | ||||||||||||||
155Hf | 72 | 83 | 154.96317(32)# | 843(30) ms | β+ | 155Lu | 7/2−# | ||||||||||||
156Hf | 72 | 84 | 155.95940(16) | 23(1) ms | α | 152Yb | 0+ | ||||||||||||
156mHf | 1958.8(10) keV | 480(40) μs | α | 152Yb | (8+) | ||||||||||||||
157Hf | 72 | 85 | 156.95829(22)# | 115(1) ms | α (94%) | 153Yb | 7/2− | ||||||||||||
β+ (6%) | 157Lu | ||||||||||||||||||
158Hf | 72 | 86 | 157.954801(19) | 2.85(7) s | β+ (55.7%) | 158Lu | 0+ | ||||||||||||
α (44.3%) | 154Yb | ||||||||||||||||||
159Hf | 72 | 87 | 158.953996(18) | 5.20(10) s | β+ (65%) | 159Lu | 7/2− | ||||||||||||
α (35%) | 155Yb | ||||||||||||||||||
160Hf | 72 | 88 | 159.950683(10) | 13.6(2) s | β+ (99.3%) | 160Lu | 0+ | ||||||||||||
α (0.7%) | 156Yb | ||||||||||||||||||
161Hf | 72 | 89 | 160.950278(25) | 18.4(4) s | β+ (99.71%) | 161Lu | (7/2−) | ||||||||||||
α (0.29%) | 157Yb | ||||||||||||||||||
161mHf | 329.0(5) keV | 4.8(2) μs | IT | 161Hf | (13/2+) | ||||||||||||||
162Hf | 72 | 90 | 161.9472155(96) | 39.4(9) s | β+ (99.99%) | 162Lu | 0+ | ||||||||||||
α (0.008%) | 158Yb | ||||||||||||||||||
163Hf | 72 | 91 | 162.947107(28) | 40.0(6) s | β+ | 163Lu | (5/2−) | ||||||||||||
164Hf | 72 | 92 | 163.944371(17) | 111(8) s | β+ | 164Lu | 0+ | ||||||||||||
165Hf | 72 | 93 | 164.944567(30) | 76(4) s | β+ | 165Lu | (5/2−) | ||||||||||||
166Hf | 72 | 94 | 165.942180(30) | 6.77(30) min | β+ | 166Lu | 0+ | ||||||||||||
167Hf | 72 | 95 | 166.942600(30) | 2.05(5) min | β+ | 167Lu | (5/2)− | ||||||||||||
168Hf | 72 | 96 | 167.940568(30) | 25.95(20) min | EC (98%) | 168Lu | 0+ | ||||||||||||
β+ (2%) | 168Lu | ||||||||||||||||||
169Hf | 72 | 97 | 168.941259(30) | 3.24(4) min | β+ | 169Lu | (5/2−) | ||||||||||||
170Hf | 72 | 98 | 169.939609(30) | 16.01(13) h | EC | 170Lu | 0+ | ||||||||||||
171Hf | 72 | 99 | 170.940492(31) | 12.1(4) h | β+ | 171Lu | 7/2+ | ||||||||||||
171mHf | 21.93(9) keV | 29.5(9) s | IT | 171Hf | 1/2− | ||||||||||||||
172Hf | 72 | 100 | 171.939450(26) | 1.87(3) y | EC | 172Lu | 0+ | ||||||||||||
172mHf | 2005.84(11) keV | 163(3) ns | IT | 172Hf | (8−) | ||||||||||||||
173Hf | 72 | 101 | 172.940513(30) | 23.6(1) h | β+ | 173Lu | 1/2− | ||||||||||||
173m1Hf | 107.16(5) keV | 180(8) ns | IT | 173Hf | 5/2− | ||||||||||||||
173m2Hf | 197.47(10) keV | 160(40) ns | IT | 173Hf | 7/2+ | ||||||||||||||
174Hf[n 9] | 72 | 102 | 173.9400484(24) | 3.8+1.7 −0.9×1016 y[2] |
α[n 10] | 170Yb | 0+ | 0.0016(12) | |||||||||||
174m1Hf | 1549.26(4) keV | 138(4) ns | IT | 174Hf | 6+ | ||||||||||||||
174m2Hf | 1797.59(7) keV | 2.39(4) μs | IT | 174Hf | 8− | ||||||||||||||
174m3Hf | 3312.07(6) keV | 3.7(2) μs | IT | 174Hf | 14+ | ||||||||||||||
175Hf | 72 | 103 | 174.9415114(25) | 69.90(7) d[3] | EC | 175Lu | 5/2− | ||||||||||||
175m1Hf | 125.89(12) keV | 53.7(15) μs | IT | 175Hf | 1/2− | ||||||||||||||
175m2Hf | 1433.41(12) keV | 1.10(8) μs | IT | 175Hf | 19/2+ | ||||||||||||||
175m3Hf | 3015.6(4) keV | 1.21(15) μs | IT | 175Hf | 35/2− | ||||||||||||||
175m4Hf | 4636.2(12) keV | 1.9(1) μs | IT | 175Hf | 45/2+ | ||||||||||||||
176Hf[n 11] | 72 | 104 | 175.9414098(16) | Observationally Stable[n 12] | 0+ | 0.0526(70) | |||||||||||||
176m1Hf | 1333.07(7) keV | 9.6(3) μs | IT | 176Hf | 6+ | ||||||||||||||
176m2Hf | 1559.31(9) keV | 9.9(2) μs | IT | 176Hf | 8− | ||||||||||||||
176m3Hf | 2865.8(7) keV | 401(6) μs | IT | 176Hf | 14− | ||||||||||||||
176m4Hf | 4863.6(9) keV | 43(4) μs | IT | 176Hf | 22− | ||||||||||||||
177Hf | 72 | 105 | 176.9432302(15) | Observationally Stable[n 13] | 7/2− | 0.1860(16) | |||||||||||||
177m1Hf | 1315.4502(8) keV | 1.09(5) s | IT | 177Hf | 23/2+ | ||||||||||||||
177m2Hf | 1342.4(10) keV | 55.9(12) μs | IT | 177Hf | (19/2−) | ||||||||||||||
177m3Hf | 2740.02(15) keV | 51.4(5) min | IT | 177Hf | 37/2− | ||||||||||||||
178Hf | 72 | 106 | 177.9437083(15) | Observationally Stable[n 14] | 0+ | 0.2728(28) | |||||||||||||
178m1Hf | 1147.416(6) keV | 4.0(2) s | IT | 178Hf | 8− | ||||||||||||||
178m2Hf | 2446.09(8) keV | 31(1) y | IT | 178Hf | 16+ | ||||||||||||||
178m3Hf | 2572.4(3) keV | 68(2) μs | IT | 178Hf | 14− | ||||||||||||||
179Hf | 72 | 107 | 178.9458257(15) | Observationally Stable[n 15] | 9/2+ | 0.1362(11) | |||||||||||||
179m1Hf | 375.0352(25) keV | 18.67(4) s | IT | 179Hf | 1/2− | ||||||||||||||
179m2Hf | 1106.412(33) keV | 25.00(17) d | IT | 179Hf | 25/2− | ||||||||||||||
179m3Hf | 3775.2(21) keV | 15(5) μs | IT | 179Hf | (43/2+) | ||||||||||||||
180Hf | 72 | 108 | 179.9465595(15) | Observationally Stable[n 16] | 0+ | 0.3508(33) | |||||||||||||
180m1Hf | 1141.552(15) keV | 5.53(2) h | IT (99.69%) | 180Hf | 8− | ||||||||||||||
β− (0.31%) | 180m1Ta[8] | ||||||||||||||||||
180m2Hf | 1374.36(4) keV | 570(20) μs | IT | 180Hf | 4− | ||||||||||||||
180m3Hf | 2485.5(5) keV | 0.94(11) μs | IT | 180Hf | 12+ | ||||||||||||||
180m4Hf | 3599.0(10) keV | 90(10) μs | IT | 180Hf | (18−) | ||||||||||||||
181Hf | 72 | 109 | 180.9491108(15) | 42.39(6) d | β− | 181Ta | 1/2− | ||||||||||||
181m1Hf | 595.27(4) keV | 80(5) μs | IT | 181Hf | (9/2+) | ||||||||||||||
181m2Hf | 1043.5(8) keV | ~100 μs | IT | 181Hf | (17/2+) | ||||||||||||||
181m3Hf | 1741.9(13) keV | 1.5(5) ms | IT | 181Hf | (25/2−) | ||||||||||||||
182Hf[n 17] | 72 | 110 | 181.9505637(66) | 8.90(9)×106 y | β− | 182Ta | 0+ | ||||||||||||
182m1Hf | 1172.87(18) keV | 61.5(15) min | β− (54%) | 182Ta | 8− | ||||||||||||||
IT (46%) | 182Hf | ||||||||||||||||||
182m2Hf | 2571.3(12) keV | 40(10) μs | IT | 182Hf | (13+) | ||||||||||||||
183Hf | 72 | 111 | 182.953533(32) | 1.018(2) h | β− | 183Ta | (3/2−) | ||||||||||||
183mHf | 1464(64) keV | 40(30) s | IT | 183Hf | 27/2−# | ||||||||||||||
184Hf | 72 | 112 | 183.955449(43) | 4.12(5) h | β− | 184Ta | 0+ | ||||||||||||
184m1Hf | 1272.2(4) keV | 48(10) s | IT | 184Hf | 8− | ||||||||||||||
184m2Hf | 2477(10) keV | 16(7) min | 15+# | ||||||||||||||||
185Hf | 72 | 113 | 184.958862(69) | 3.5(6) min | β− | 185Ta | (9/2−) | ||||||||||||
186Hf | 72 | 114 | 185.960897(55) | 2.6(12) min | β− | 186Ta | 0+ | ||||||||||||
186mHf | 2968(43) keV | >20 s | 17+# | ||||||||||||||||
187Hf | 72 | 115 | 186.96457(22)# | 14# s [>300 ns] |
9/2−# | ||||||||||||||
187mHf | 500(300)# keV | 270(80) ns | IT | 187Hf | 3/2−# | ||||||||||||||
188Hf | 72 | 116 | 187.96690(32)# | 7# s [>300 ns] |
0+ | ||||||||||||||
189Hf | 72 | 117 | 188.97085(32)# | 400# ms [>300 ns] |
3/2−# | ||||||||||||||
190Hf | 72 | 118 | 189.97338(43)# | 600# ms [>300 ns] |
0+ | ||||||||||||||
191Hf[9] | 72 | 119 | |||||||||||||||||
192Hf[9] | 72 | 120 | 0+ | ||||||||||||||||
This table header & footer: |
- ^ mHf – 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).
- ^ Bold half-life – nearly stable, half-life longer than age of universe.
- ^ a b c # – 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 - ^ Bold symbol as daughter – Daughter product is stable.
- ^ ( ) spin value – Indicates spin with weak assignment arguments.
- ^ primordial radionuclide
- ^ Theorized to also undergo β+β+ decay to 174Yb
- ^ Used in lutetium-hafnium dating
- ^ Believed to undergo α decay to 172Yb
- ^ Believed to undergo α decay to 173Yb with a half-life over 1.3×1018 y.
- ^ Believed to undergo α decay to 174Yb
- ^ Believed to undergo α decay to 175Yb
- ^ Believed to undergo α decay to 176Yb
- ^ Extinct radionuclide, used in hafnium–tungsten dating[6]
See also
[edit]Daughter products other than hafnium
References
[edit]- ^ a b c d e Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3) 030001. doi:10.1088/1674-1137/abddae.
- ^ a b c Belli, P.; Bernabei, R.; Cappella, F.; Caracciolo, V.; Cerulli, R.; Incicchitti, A.; Laubenstein, M.; Leoncini, A.; Merlo, V.; Nagorny, S.S.; Nahorna, V.V.; Nisi, S.; Wang, P. (January 2025). "A new measurement of 174Hf alpha decay". Nuclear Physics A. 1053 122976. doi:10.1016/j.nuclphysa.2024.122976.
- ^ a b Kmak, K. N.; Neupane, S.; Kolos, K.; et al. (2025). "Measurement of the 175Hf half-life". Physical Review C. 111 (024308). doi:10.1103/PhysRevC.111.024308.
- ^ "Standard Atomic Weights: Hafnium". CIAAW. 2019.
- ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
- ^ a b Kleine T, Walker RJ (August 2017). "Tungsten Isotopes in Planets". Annual Review of Earth and Planetary Sciences. 45 (1): 389–417. Bibcode:2017AREPS..45..389K. doi:10.1146/annurev-earth-063016-020037. PMC 6398955. PMID 30842690.
- ^ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3) 030003. doi:10.1088/1674-1137/abddaf.
- ^ McCutchan, E.A. (May 2015). "Nuclear Data Sheets for A = 180". Nuclear Data Sheets. 126: 151–372. doi:10.1016/j.nds.2015.05.002.
- ^ a b Haak, K.; Tarasov, O. B.; Chowdhury, P.; et al. (2023). "Production and discovery of neutron-rich isotopes by fragmentation of 198Pt". Physical Review C. 108 (34608): 034608. Bibcode:2023PhRvC.108c4608H. doi:10.1103/PhysRevC.108.034608. S2CID 261649436.
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