Isotopes of hafnium explained

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 years. In addition, there are 34 known synthetic radioisotopes, the most stable of which is ¹⁸²Hf with a half-life of years. This extinct radionuclide is used in hafnium–tungsten dating to study the chronology of planetary differentiation.^[1]

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.

List of isotopes

|-174| ¹⁵³Hf| style="text-align:right" | 72| style="text-align:right" | 81| 152.97069(54)#| 400# ms [>200 ns]||| 1/2+#|||-id=Hafnium-153m| style="text-indent:1em" | ^153mHf| colspan="3" style="text-indent:2em" | 750(100)# keV| 500# ms||| 11/2−#|||-id=Hafnium-154| rowspan=2|¹⁵⁴Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 82| rowspan=2|153.96486(54)#| rowspan=2|2(1) s| β⁺| ¹⁵⁴Lu| rowspan=2|0+| rowspan=2|| rowspan=2||-| α (rare)| ¹⁵⁰Yb|-id=Hafnium-155| rowspan=2|¹⁵⁵Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 83| rowspan=2|154.96339(43)#| rowspan=2|890(120) ms| β⁺| ¹⁵⁵Lu| rowspan=2|7/2−#| rowspan=2|| rowspan=2||-| α (rare)| ¹⁵¹Yb|-id=Hafnium-156| rowspan=2|¹⁵⁶Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 84| rowspan=2|155.95936(22)| rowspan=2|23(1) ms| α (97%)| ¹⁵²Yb| rowspan=2|0+| rowspan=2|| rowspan=2||-| β⁺ (3%)| ¹⁵⁶Lu|-id=Hafnium-156m| style="text-indent:1em" | ^156mHf| colspan="3" style="text-indent:2em" | 1959.0(10) keV| 480(40) μs||| 8+|||-id=Hafnium-157| rowspan=2|¹⁵⁷Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 85| rowspan=2|156.95840(21)#| rowspan=2|115(1) ms| α (86%)| ¹⁵³Yb| rowspan=2|7/2−| rowspan=2|| rowspan=2||-| β⁺ (14%)| ¹⁵⁷Lu|-id=Hafnium-158| rowspan=2|¹⁵⁸Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 86| rowspan=2|157.954799(19)| rowspan=2|2.84(7) s| β⁺ (55%)| ¹⁵⁸Lu| rowspan=2|0+| rowspan=2|| rowspan=2||-| α (45%)| ¹⁵⁴Yb|-id=Hafnium-159| rowspan=2|¹⁵⁹Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 87| rowspan=2|158.953995(18)| rowspan=2|5.20(10) s| β⁺ (59%)| ¹⁵⁹Lu| rowspan=2|7/2−#| rowspan=2|| rowspan=2||-| α (41%)| ¹⁵⁵Yb|-id=Hafnium-160| rowspan=2|¹⁶⁰Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 88| rowspan=2|159.950684(12)| rowspan=2|13.6(2) s| β⁺ (99.3%)| ¹⁶⁰Lu| rowspan=2|0+| rowspan=2|| rowspan=2||-| α (.7%)| ¹⁵⁶Yb|-id=Hafnium-161| rowspan=2|¹⁶¹Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 89| rowspan=2|160.950275(24)| rowspan=2|18.2(5) s| β⁺ (99.7%)| ¹⁶¹Lu| rowspan=2|3/2−#| rowspan=2|| rowspan=2||-| α (.3%)| ¹⁵⁷Yb|-id=Hafnium-162| rowspan=2|¹⁶²Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 90| rowspan=2|161.94721(1)| rowspan=2|39.4(9) s| β⁺ (99.99%)| ¹⁶²Lu| rowspan=2|0+| rowspan=2|| rowspan=2||-| α (.008%)| ¹⁵⁸Yb|-id=Hafnium-163| rowspan=2|¹⁶³Hf| rowspan=2 style="text-align:right" | 72| rowspan=2 style="text-align:right" | 91| rowspan=2|162.94709(3)| rowspan=2|40.0(6) s| β⁺| ¹⁶³Lu| rowspan=2|3/2−#| rowspan=2|| rowspan=2||-| α (10⁻⁴%)| ¹⁵⁹Yb|-id=Hafnium-164| ¹⁶⁴Hf| style="text-align:right" | 72| style="text-align:right" | 92| 163.944367(22)| 111(8) s| β⁺| ¹⁶⁴Lu| 0+|||-id=Hafnium-165| ¹⁶⁵Hf| style="text-align:right" | 72| style="text-align:right" | 93| 164.94457(3)| 76(4) s| β⁺| ¹⁶⁵Lu| (5/2−)|||-id=Hafnium-166| ¹⁶⁶Hf| style="text-align:right" | 72| style="text-align:right" | 94| 165.94218(3)| 6.77(30) min| β⁺| ¹⁶⁶Lu| 0+|||-id=Hafnium-167| ¹⁶⁷Hf| style="text-align:right" | 72| style="text-align:right" | 95| 166.94260(3)| 2.05(5) min| β⁺| ¹⁶⁷Lu| (5/2)−|||-id=Hafnium-168| ¹⁶⁸Hf| style="text-align:right" | 72| style="text-align:right" | 96| 167.94057(3)| 25.95(20) min| β⁺| ¹⁶⁸Lu| 0+|||-id=Hafnium-169| ¹⁶⁹Hf| style="text-align:right" | 72| style="text-align:right" | 97| 168.94126(3)| 3.24(4) min| β⁺| ¹⁶⁹Lu| (5/2)−|||-id=Hafnium-170| ¹⁷⁰Hf| style="text-align:right" | 72| style="text-align:right" | 98| 169.93961(3)| 16.01(13) h| EC| ¹⁷⁰Lu| 0+|||-id=Hafnium-171| ¹⁷¹Hf| style="text-align:right" | 72| style="text-align:right" | 99| 170.94049(3)| 12.1(4) h| β⁺| ¹⁷¹Lu| 7/2(+)|||-id=Hafnium-171m| style="text-indent:1em" | ^171mHf| colspan="3" style="text-indent:2em" | 21.93(9) keV| 29.5(9) s| IT| ¹⁷¹Hf| 1/2(−)|||-id=Hafnium-172| ¹⁷²Hf| style="text-align:right" | 72| style="text-align:right" | 100| 171.939448(26)| 1.87(3) y| EC| ¹⁷²Lu| 0+|||-id=Hafnium-172m| style="text-indent:1em" | ^172mHf| colspan="3" style="text-indent:2em" | 2005.58(11) keV| 163(3) ns||| (8−)|||-id=Hafnium-173| ¹⁷³Hf| style="text-align:right" | 72| style="text-align:right" | 101| 172.94051(3)| 23.6(1) h| β⁺| ¹⁷³Lu| 1/2−|||-id=Hafnium-174| ¹⁷⁴Hf^[2] | style="text-align:right" | 72| style="text-align:right" | 102| 173.940046(3)| 7.0(12)×10¹⁶ y| α^[3] | ¹⁷⁰Yb| 0+| 0.0016(1)| 0.001619–0.001621|-id=Hafnium-174m1| style="text-indent:1em" | ^174m1Hf| colspan="3" style="text-indent:2em" | 1549.3 keV| 138(4) ns||| (6+)|||-id=Hafnium-174m2| style="text-indent:1em" | ^174m2Hf| colspan="3" style="text-indent:2em" | 1797.5(20) keV| 2.39(4) μs||| (8−)|||-id=Hafnium-174m3| style="text-indent:1em" | ^174m3Hf| colspan="3" style="text-indent:2em" | 3311.7 keV| 3.7(2) μs||| (14+)|||-id=Hafnium-175| ¹⁷⁵Hf| style="text-align:right" | 72| style="text-align:right" | 103| 174.941509(3)| 70(2) d| β⁺| ¹⁷⁵Lu| 5/2−|||-id=Hafnium-176| ¹⁷⁶Hf^[4] | style="text-align:right" | 72| style="text-align:right" | 104| 175.9414086(24)| colspan=3 align=center|Observationally Stable^[5] | 0+| 0.0526(7)| 0.05206–0.05271|-id=Hafnium-176m1| style="text-indent:1em" | ^176m1Hf| colspan="3" style="text-indent:2em" | 1333.07(7) keV| 9.6(3) μs| IT| ¹⁷⁶Hf| 6+|||-id=Hafnium-176m2| style="text-indent:1em" | ^176m2Hf| colspan="3" style="text-indent:2em" | 1559.31(9) keV| 9.9(2) μs| IT| ¹⁷⁶Hf| 8−|||-id=Hafnium-176m3| style="text-indent:1em" | ^176m3Hf| colspan="3" style="text-indent:2em" | 2865.8(7) keV| 401(6) μs| IT| ¹⁷⁶Hf| 14−|||-id=Hafnium-176m4| style="text-indent:1em" | ^176m4Hf| colspan="3" style="text-indent:2em" | 4863.6(9) keV| 43(4) μs| IT| ¹⁷⁶Hf| 22−|||-id=Hafnium-177| ¹⁷⁷Hf| style="text-align:right" | 72| style="text-align:right" | 105| 176.9432207(23)| colspan=3 align=center|Observationally Stable^[6] | 7/2−| 0.1860(9)| 0.18593–0.18606|-id=Hafnium-177m1| style="text-indent:1em" | ^177m1Hf| colspan="3" style="text-indent:2em" | 1315.4504(8) keV| 1.09(5) s||| 23/2+|||-id=Hafnium-177m2| style="text-indent:1em" | ^177m2Hf| colspan="3" style="text-indent:2em" | 1342.38(20) keV| 55.9(12) μs||| (19/2−)|||-id=Hafnium-177m3| style="text-indent:1em" | ^177m3Hf| colspan="3" style="text-indent:2em" | 2740.02(15) keV| 51.4(5) min||| 37/2−|||-id=Hafnium-178| ¹⁷⁸Hf| style="text-align:right" | 72| style="text-align:right" | 106| 177.9436988(23)| colspan=3 align=center|Observationally Stable^[7] | 0+| 0.2728(7)| 0.27278–0.27297|-id=Hafnium-178m1| style="text-indent:1em" | ^178m1Hf| colspan="3" style="text-indent:2em" | 1147.423(5) keV| 4.0(2) s||| 8−|||-id=Hafnium-178m2| style="text-indent:1em" | ^178m2Hf| colspan="3" style="text-indent:2em" | 2445.69(11) keV| 31(1) y||| 16+|||-id=Hafnium-178m3| style="text-indent:1em" | ^178m3Hf| colspan="3" style="text-indent:2em" | 2573.5(5) keV| 68(2) μs||| (14−)|||-id=Hafnium-179| ¹⁷⁹Hf| style="text-align:right" | 72| style="text-align:right" | 107| 178.9458161(23)| colspan=3 align=center|Observationally Stable^[8] | 9/2+| 0.1362(2)| 0.13619–0.1363|-id=Hafnium-179m1| style="text-indent:1em" | ^179m1Hf| colspan="3" style="text-indent:2em" | 375.0367(25) keV| 18.67(4) s||| 1/2−|||-id=Hafnium-179m2| style="text-indent:1em" | ^179m2Hf| colspan="3" style="text-indent:2em" | 1105.84(19) keV| 25.05(25) d||| 25/2−|||-id=Hafnium-180| ¹⁸⁰Hf| style="text-align:right" | 72| style="text-align:right" | 108| 179.9465500(23)| colspan=3 align=center|Observationally Stable^[9] | 0+| 0.3508(16)| 0.35076–0.351|-id=Hafnium-180m1| style="text-indent:1em" | ^180m1Hf| colspan="3" style="text-indent:2em" | 1141.48(4) keV| 5.47(4) h||| 8−|||-id=Hafnium-180m2| style="text-indent:1em" | ^180m2Hf| colspan="3" style="text-indent:2em" | 1374.15(4) keV| 0.57(2) μs||| (4−)|||-id=Hafnium-180m3| style="text-indent:1em" | ^180m3Hf| colspan="3" style="text-indent:2em" | 2425.8(10) keV| 15(5) μs||| (10+)|||-id=Hafnium-180m4| style="text-indent:1em" | ^180m4Hf| colspan="3" style="text-indent:2em" | 2486.3(9) keV| 10(1) μs||| 12+|||-id=Hafnium-180m5| style="text-indent:1em" | ^180m5Hf| colspan="3" style="text-indent:2em" | 2538.3(12) keV| >10 μs||| (14+)|||-id=Hafnium-180m6| style="text-indent:1em" | ^180m6Hf| colspan="3" style="text-indent:2em" | 3599.3(18) keV| 90(10) μs||| (18−)|||-id=Hafnium-181| ¹⁸¹Hf| style="text-align:right" | 72| style="text-align:right" | 109| 180.9491012(23)| 42.39(6) d| β⁻| ¹⁸¹Ta| 1/2−|||-id=Hafnium-181m1| style="text-indent:1em" | ^181m1Hf| colspan="3" style="text-indent:2em" | 595(3) keV| 80(5) μs||| (9/2+)|||-id=Hafnium-181m2| style="text-indent:1em" | ^181m2Hf| colspan="3" style="text-indent:2em" | 1040(10) keV| ~100 μs||| (17/2+)|||-id=Hafnium-181m3| style="text-indent:1em" | ^181m3Hf| colspan="3" style="text-indent:2em" | 1738(10) keV| 1.5(5) ms||| (27/2−)|||-id=Hafnium-182| ¹⁸²Hf| style="text-align:right" | 72| style="text-align:right" | 110| 181.950554(7)| 8.90(9)×10⁶ y| β⁻| ¹⁸²Ta| 0+|||-id=Hafnium-182m| rowspan=2 style="text-indent:1em" | ^182mHf| rowspan=2 colspan="3" style="text-indent:2em" | 1172.88(18) keV| rowspan=2|61.5(15) min| β⁻ (58%)| ¹⁸²Ta| rowspan=2|8−| rowspan=2|| rowspan=2||-| IT (42%)| ¹⁸²Hf|-id=Hafnium-183| ¹⁸³Hf| style="text-align:right" | 72| style="text-align:right" | 111| 182.95353(3)| 1.067(17) h| β⁻| ¹⁸³Ta| (3/2−)|||-id=Hafnium-184| ¹⁸⁴Hf| style="text-align:right" | 72| style="text-align:right" | 112| 183.95545(4)| 4.12(5) h| β⁻| ¹⁸⁴Ta| 0+|||-id=Hafnium-184m| style="text-indent:1em" | ^184mHf| colspan="3" style="text-indent:2em" | 1272.4(4) keV| 48(10) s| β⁻| ¹⁸⁴Ta| 8−|||-id=Hafnium-185| ¹⁸⁵Hf| style="text-align:right" | 72| style="text-align:right" | 113| 184.95882(21)#| 3.5(6) min| β⁻| ¹⁸⁵Ta| 3/2−#|||-id=Hafnium-186| ¹⁸⁶Hf| style="text-align:right" | 72| style="text-align:right" | 114| 185.96089(32)#| 2.6(12) min| β⁻| ¹⁸⁶Ta| 0+|||-id=Hafnium-187| ¹⁸⁷Hf| style="text-align:right" | 72| style="text-align:right" | 115| 186.96457(22)#| 14# s [>300 ns]||| 9/2−#|||-id=Hafnium-187m| style="text-indent:1em" | ^187mHf| colspan="3" style="text-indent:2em" |500(300)# keV| 270(80) ns| IT| ¹⁸⁷Hf| 3/2−#|||-id=Hafnium-188| ¹⁸⁸Hf| style="text-align:right" | 72| style="text-align:right" | 116| 187.96690(32)#| 20# s [>300 ns]||| 0+|||-id=Hafnium-189| ¹⁸⁹Hf| style="text-align:right" | 72| style="text-align:right" | 117| 188.97085(32)#| 400# ms [>300 ns]||| 3/2−#|||-id=Hafnium-190| ¹⁹⁰Hf| style="text-align:right" | 72| style="text-align:right" | 118| 189.97338(43)#| 600# ms [>300 ns]||| 0+|||-id=Hafnium-191| ¹⁹¹Hf^[10] | style="text-align:right" | 72| style="text-align:right" | 119| |||| |||-id=Hafnium-192| ¹⁹²Hf^[10] | style="text-align:right" | 72| style="text-align:right" | 120| |||| 0+||

References

• Isotope masses from:
  • • Isotopic compositions and standard atomic masses from:
      • • Half-life, spin, and isomer data selected from the following sources.

Notes and References

1. Kleine T, Walker RJ . Tungsten Isotopes in Planets . Annual Review of Earth and Planetary Sciences . 45 . 1 . 389–417 . August 2017 . 30842690 . 6398955 . 10.1146/annurev-earth-063016-020037 . 2017AREPS..45..389K .
2. [Primordial nuclide|primordial]
3. Theorized to also undergo β⁺β⁺ decay to ¹⁷⁴Yb
4. Used in lutetium-hafnium dating
5. Believed to undergo α decay to ¹⁷²Yb
6. Believed to undergo α decay to ¹⁷³Yb
7. Believed to undergo α decay to ¹⁷⁴Yb
8. Believed to undergo α decay to ¹⁷⁵Yb
9. Believed to undergo α decay to ¹⁷⁶Yb
10. K. . Haak . O. B. . Tarasov . P. . Chowdhury . et al. . Production and discovery of neutron-rich isotopes by fragmentation of ¹⁹⁸Pt . 2023 . Physical Review C . 108 . 34608 . 034608 . 10.1103/PhysRevC.108.034608. 2023PhRvC.108c4608H . 261649436 .