Isotopes of hafnium (original) (raw)

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Isotopes of hafnium (72Hf)

Main isotopes[1] Decay abun­dance half-life (_t_1/2) mode pro­duct 172Hf synth 1.87 y ε 172Lu 174Hf 0.16% 3.8×1016 y[2] α 170Yb 176Hf 5.26% stable 177Hf 18.6% stable 178Hf 27.3% stable 178m2Hf synth 31 y IT 178Hf 179Hf 13.6% stable 180Hf 35.1% stable 182Hf synth 8.9×106 y β− 182Ta
Standard atomic weight _A_r°(Hf)
178.486±0.006[3]178.49±0.01 (abridged)[4]
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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] 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.[5]

No other radioisotope has a half-life over 1.87 years. Most isotopes have half-lives under 1 minute. There are also at least 27 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.

| Nuclide[n 1] | Z | N | Isotopic mass (Da)[6][n 2][n 3] | Half-life[1][n 4][n 5] | Decay mode[1][n 6] | Daughter isotope[n 7] | Spin andparity[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) | 70.65(19) d | 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[7] | | | | | | | | | | 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[8] | 72 | 119 | | | | | | | | | 192Hf[8] | 72 | 120 | | | | | 0+ | | | | This table header & footer: view | | | | | | | | | |

  1. ^ mHf – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1_σ_) is given in concise form in parentheses after the corresponding last digits.
  3. ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ^ Bold half-life – nearly stable, half-life longer than age of universe.
  5. ^ a b c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  6. ^ Modes of decay:
  7. ^ Bold symbol as daughter – Daughter product is stable.
  8. ^ ( ) spin value – Indicates spin with weak assignment arguments.
  9. ^ primordial radionuclide
  10. ^ Theorized to also undergo β+β+ decay to 174Yb
  11. ^ Used in lutetium-hafnium dating
  12. ^ Believed to undergo α decay to 172Yb
  13. ^ Believed to undergo α decay to 173Yb with a half-life over 1.3×1018 y.
  14. ^ Believed to undergo α decay to 174Yb
  15. ^ Believed to undergo α decay to 175Yb
  16. ^ Believed to undergo α decay to 176Yb
  17. ^ Extinct radionuclide, used in hafnium–tungsten dating[5]

Daughter products other than hafnium

  1. ^ 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.
  2. ^ 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.
  3. ^ "Standard Atomic Weights: Hafnium". CIAAW. 2019.
  4. ^ 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.
  5. ^ 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.
  6. ^ 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.
  7. ^ 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.
  8. ^ 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.