Natural

hafnium Hafnium is a chemical element with the symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri M ...

(₇₂Hf) consists of five 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 numbers) ...

s (¹⁷⁶Hf, ¹⁷⁷Hf, ¹⁷⁸Hf, ¹⁷⁹Hf, and ¹⁸⁰Hf) and one very long-lived

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 ...

, ¹⁷⁴Hf, 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 ato ...

of years. In addition, there are 30 known

synthetic radioisotope A synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. Examples include technetium-95 and prometh ...

s, the most stable of which is ¹⁸²Hf with a half-life of years. This

extinct radionuclide An extinct radionuclide is a radionuclide that was formed by nucleosynthesis before the formation of the Solar System, about 4.6 billion years ago, but has since decayed to virtually zero abundance and is no longer detectable as a primordial nucl ...

is used in

hafnium–tungsten dating Hafnium–tungsten dating is a Geochronology, geochronological radiometric dating method utilizing the radioactive decay system of isotopes of hafnium, hafnium-182 to isotopes of tungsten, tungsten-182. The half-life of the system is million ...

to study the chronology of

planetary differentiation In planetary science, planetary differentiation is the process by which the chemical elements of a planetary body accumulate in different areas of that body, due to their physical or chemical behavior (e.g. density and chemical affinities). The ...

. No other radioisotope has a half-life over 1.87 years. Most isotopes have half-lives under 1 minute. There are also 26 known

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

s, the most stable of which is ^178m2Hf with a half-life of 31 years. All isotopes of hafnium are either radioactive or

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 ...

, meaning that they are predicted to be radioactive but no actual decay has been observed.

List of isotopes

, - , ¹⁵³Hf , style="text-align:right" , 72 , style="text-align:right" , 81 , 152.97069(54)# , 400# ms 200 ns, , , 1/2+# , , , - , style="text-indent:1em" , ^153mHf , colspan="3" style="text-indent:2em" , 750(100)# keV , 500# ms , , , 11/2−# , , , - , 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 , - , 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 , - , 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 , - , style="text-indent:1em" , ^156mHf , colspan="3" style="text-indent:2em" , 1959.0(10) keV , 480(40) μs , , , 8+ , , , - , 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 , - , 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 , - , 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 , - , 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 , - , 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 , - , 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 , - , 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 , - , ¹⁶⁴Hf , style="text-align:right" , 72 , style="text-align:right" , 92 , 163.944367(22) , 111(8) s , β⁺ , ¹⁶⁴Lu , 0+ , , , - , ¹⁶⁵Hf , style="text-align:right" , 72 , style="text-align:right" , 93 , 164.94457(3) , 76(4) s , β⁺ , ¹⁶⁵Lu , (5/2−) , , , - , ¹⁶⁶Hf , style="text-align:right" , 72 , style="text-align:right" , 94 , 165.94218(3) , 6.77(30) min , β⁺ , ¹⁶⁶Lu , 0+ , , , - , ¹⁶⁷Hf , style="text-align:right" , 72 , style="text-align:right" , 95 , 166.94260(3) , 2.05(5) min , β⁺ , ¹⁶⁷Lu , (5/2)− , , , - , ¹⁶⁸Hf , style="text-align:right" , 72 , style="text-align:right" , 96 , 167.94057(3) , 25.95(20) min , β⁺ , ¹⁶⁸Lu , 0+ , , , - , ¹⁶⁹Hf , style="text-align:right" , 72 , style="text-align:right" , 97 , 168.94126(3) , 3.24(4) min , β⁺ , ¹⁶⁹Lu , (5/2)− , , , - , ¹⁷⁰Hf , style="text-align:right" , 72 , style="text-align:right" , 98 , 169.93961(3) , 16.01(13) h , EC , ¹⁷⁰Lu , 0+ , , , - , ¹⁷¹Hf , style="text-align:right" , 72 , style="text-align:right" , 99 , 170.94049(3) , 12.1(4) h , β⁺ , ¹⁷¹Lu , 7/2(+) , , , - , style="text-indent:1em" , ^171mHf , colspan="3" style="text-indent:2em" , 21.93(9) keV , 29.5(9) s , IT , ¹⁷¹Hf , 1/2(−) , , , - , ¹⁷²Hf , style="text-align:right" , 72 , style="text-align:right" , 100 , 171.939448(26) , 1.87(3) y , EC , ¹⁷²Lu , 0+ , , , - , style="text-indent:1em" , ^172mHf , colspan="3" style="text-indent:2em" , 2005.58(11) keV , 163(3) ns , , , (8−) , , , - , ¹⁷³Hf , style="text-align:right" , 72 , style="text-align:right" , 101 , 172.94051(3) , 23.6(1) h , β⁺ , ¹⁷³Lu , 1/2− , , , - , ¹⁷⁴Hf primordial

radionuclide 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; transfer ...

, style="text-align:right" , 72 , style="text-align:right" , 102 , 173.940046(3) , 7.0(12)×10¹⁶ y , α , ¹⁷⁰Yb , 0+ , 0.0016(1) , 0.001619–0.001621 , - , style="text-indent:1em" , ^174m1Hf , colspan="3" style="text-indent:2em" , 1549.3 keV , 138(4) ns , , , (6+) , , , - , style="text-indent:1em" , ^174m2Hf , colspan="3" style="text-indent:2em" , 1797.5(20) keV , 2.39(4) μs , , , (8−) , , , - , style="text-indent:1em" , ^174m3Hf , colspan="3" style="text-indent:2em" , 3311.7 keV , 3.7(2) μs , , , (14+) , , , - , ¹⁷⁵Hf , style="text-align:right" , 72 , style="text-align:right" , 103 , 174.941509(3) , 70(2) d , β⁺ , ¹⁷⁵Lu , 5/2− , , , - , ¹⁷⁶HfUsed in lutetium-hafnium dating , style="text-align:right" , 72 , style="text-align:right" , 104 , 175.9414086(24) , 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 ¹⁷²Yb , 0+ , 0.0526(7) , 0.05206–0.05271 , - , ¹⁷⁷Hf , style="text-align:right" , 72 , style="text-align:right" , 105 , 176.9432207(23) , colspan=3 align=center, Observationally StableBelieved to undergo α decay to ¹⁷³Yb , 7/2− , 0.1860(9) , 0.18593–0.18606 , - , style="text-indent:1em" , ^177m1Hf , colspan="3" style="text-indent:2em" , 1315.4504(8) keV , 1.09(5) s , , , 23/2+ , , , - , style="text-indent:1em" , ^177m2Hf , colspan="3" style="text-indent:2em" , 1342.38(20) keV , 55.9(12) μs , , , (19/2−) , , , - , style="text-indent:1em" , ^177m3Hf , colspan="3" style="text-indent:2em" , 2740.02(15) keV , 51.4(5) min , , , 37/2− , , , - , ¹⁷⁸Hf , style="text-align:right" , 72 , style="text-align:right" , 106 , 177.9436988(23) , colspan=3 align=center, Observationally StableBelieved to undergo α decay to ¹⁷⁴Yb , 0+ , 0.2728(7) , 0.27278–0.27297 , - , style="text-indent:1em" , ^178m1Hf , colspan="3" style="text-indent:2em" , 1147.423(5) keV , 4.0(2) s , , , 8− , , , - , style="text-indent:1em" , ^178m2Hf , colspan="3" style="text-indent:2em" , 2445.69(11) keV , 31(1) y , , , 16+ , , , - , style="text-indent:1em" , ^178m3Hf , colspan="3" style="text-indent:2em" , 2573.5(5) keV , 68(2) μs , , , (14−) , , , - , ¹⁷⁹Hf , style="text-align:right" , 72 , style="text-align:right" , 107 , 178.9458161(23) , colspan=3 align=center, Observationally StableBelieved to undergo α decay to ¹⁷⁵Yb , 9/2+ , 0.1362(2) , 0.13619–0.1363 , - , style="text-indent:1em" , ^179m1Hf , colspan="3" style="text-indent:2em" , 375.0367(25) keV , 18.67(4) s , , , 1/2− , , , - , style="text-indent:1em" , ^179m2Hf , colspan="3" style="text-indent:2em" , 1105.84(19) keV , 25.05(25) d , , , 25/2− , , , - , ¹⁸⁰Hf , style="text-align:right" , 72 , style="text-align:right" , 108 , 179.9465500(23) , colspan=3 align=center, Observationally StableBelieved to undergo α decay to ¹⁷⁶Yb , 0+ , 0.3508(16) , 0.35076–0.351 , - , style="text-indent:1em" , ^180m1Hf , colspan="3" style="text-indent:2em" , 1141.48(4) keV , 5.47(4) h , , , 8− , , , - , style="text-indent:1em" , ^180m2Hf , colspan="3" style="text-indent:2em" , 1374.15(4) keV , 0.57(2) μs , , , (4−) , , , - , style="text-indent:1em" , ^180m3Hf , colspan="3" style="text-indent:2em" , 2425.8(10) keV , 15(5) μs , , , (10+) , , , - , style="text-indent:1em" , ^180m4Hf , colspan="3" style="text-indent:2em" , 2486.3(9) keV , 10(1) μs , , , 12+ , , , - , style="text-indent:1em" , ^180m5Hf , colspan="3" style="text-indent:2em" , 2538.3(12) keV , >10 μs , , , (14+) , , , - , style="text-indent:1em" , ^180m6Hf , colspan="3" style="text-indent:2em" , 3599.3(18) keV , 90(10) μs , , , (18−) , , , - , ¹⁸¹Hf , style="text-align:right" , 72 , style="text-align:right" , 109 , 180.9491012(23) , 42.39(6) d , β⁻ , ¹⁸¹Ta , 1/2− , , , - , style="text-indent:1em" , ^181m1Hf , colspan="3" style="text-indent:2em" , 595(3) keV , 80(5) μs , , , (9/2+) , , , - , style="text-indent:1em" , ^181m2Hf , colspan="3" style="text-indent:2em" , 1040(10) keV , ~100 μs , , , (17/2+) , , , - , style="text-indent:1em" , ^181m3Hf , colspan="3" style="text-indent:2em" , 1738(10) keV , 1.5(5) ms , , , (27/2−) , , , - , ¹⁸²Hf , style="text-align:right" , 72 , style="text-align:right" , 110 , 181.950554(7) , 8.90(9)×10⁶ y , β⁻ , ¹⁸²Ta , 0+ , , , - , 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 , - , ¹⁸³Hf , style="text-align:right" , 72 , style="text-align:right" , 111 , 182.95353(3) , 1.067(17) h , β⁻ , ¹⁸³Ta , (3/2−) , , , - , ¹⁸⁴Hf , style="text-align:right" , 72 , style="text-align:right" , 112 , 183.95545(4) , 4.12(5) h , β⁻ , ¹⁸⁴Ta , 0+ , , , - , style="text-indent:1em" , ^184mHf , colspan="3" style="text-indent:2em" , 1272.4(4) keV , 48(10) s , β⁻ , ¹⁸⁴Ta , 8− , , , - , ¹⁸⁵Hf , style="text-align:right" , 72 , style="text-align:right" , 113 , 184.95882(21)# , 3.5(6) min , β⁻ , ¹⁸⁵Ta , 3/2−# , , , - , ¹⁸⁶Hf , style="text-align:right" , 72 , style="text-align:right" , 114 , 185.96089(32)# , 2.6(12) min , β⁻ , ¹⁸⁶Ta , 0+ , , , - , ¹⁸⁷Hf , style="text-align:right" , 72 , style="text-align:right" , 115 , 186.96459(43)# , 30# s 300 ns, , , , , , - , ¹⁸⁸Hf , style="text-align:right" , 72 , style="text-align:right" , 116 , 187.96685(54)# , 20# s 300 ns, , , 0+ , ,

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 Hafnium

Hafnium Hafnium is a chemical element with the symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri M ...