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Isotopes of hafnium (₇₂Hf)
Standard atomic weight Ar°(Hf)
	178.486±0.006; 178.49±0.01 (abridged);
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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 7.0×10¹⁶ 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.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life ^{[n 4]}^{[n 5]}	Decay mode ^{[n 6]}	Daughter isotope ^{[n 7]}	Spin and parity ^{[n 8]}^{[n 5]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy^{[n 5]}			Half-life ^{[n 4]}^{[n 5]}	Decay mode ^{[n 6]}	Daughter isotope ^{[n 7]}	Spin and parity ^{[n 8]}^{[n 5]}	Normal proportion	Range of variation
¹⁵³Hf	72	81	152.97069(54)#	400# ms [>200 ns]			1/2+#
^153mHf	750(100)# keV			500# ms			11/2−#
¹⁵⁴Hf	72	82	153.96486(54)#	2(1) s	β⁺	¹⁵⁴Lu	0+
¹⁵⁴Hf	72	82	153.96486(54)#	2(1) s	α (rare)	¹⁵⁰Yb	0+
¹⁵⁵Hf	72	83	154.96339(43)#	890(120) ms	β⁺	¹⁵⁵Lu	7/2−#
¹⁵⁵Hf	72	83	154.96339(43)#	890(120) ms	α (rare)	¹⁵¹Yb	7/2−#
¹⁵⁶Hf	72	84	155.95936(22)	23(1) ms	α (97%)	¹⁵²Yb	0+
¹⁵⁶Hf	72	84	155.95936(22)	23(1) ms	β⁺ (3%)	¹⁵⁶Lu	0+
^156mHf	1959.0(10) keV			480(40) μs			8+
¹⁵⁷Hf	72	85	156.95840(21)#	115(1) ms	α (86%)	¹⁵³Yb	7/2−
¹⁵⁷Hf	72	85	156.95840(21)#	115(1) ms	β⁺ (14%)	¹⁵⁷Lu	7/2−
¹⁵⁸Hf	72	86	157.954799(19)	2.84(7) s	β⁺ (55%)	¹⁵⁸Lu	0+
¹⁵⁸Hf	72	86	157.954799(19)	2.84(7) s	α (45%)	¹⁵⁴Yb	0+
¹⁵⁹Hf	72	87	158.953995(18)	5.20(10) s	β⁺ (59%)	¹⁵⁹Lu	7/2−#
¹⁵⁹Hf	72	87	158.953995(18)	5.20(10) s	α (41%)	¹⁵⁵Yb	7/2−#
¹⁶⁰Hf	72	88	159.950684(12)	13.6(2) s	β⁺ (99.3%)	¹⁶⁰Lu	0+
¹⁶⁰Hf	72	88	159.950684(12)	13.6(2) s	α (.7%)	¹⁵⁶Yb	0+
¹⁶¹Hf	72	89	160.950275(24)	18.2(5) s	β⁺ (99.7%)	¹⁶¹Lu	3/2−#
¹⁶¹Hf	72	89	160.950275(24)	18.2(5) s	α (.3%)	¹⁵⁷Yb	3/2−#
¹⁶²Hf	72	90	161.94721(1)	39.4(9) s	β⁺ (99.99%)	¹⁶²Lu	0+
¹⁶²Hf	72	90	161.94721(1)	39.4(9) s	α (.008%)	¹⁵⁸Yb	0+
¹⁶³Hf	72	91	162.94709(3)	40.0(6) s	β⁺	¹⁶³Lu	3/2−#
¹⁶³Hf	72	91	162.94709(3)	40.0(6) s	α (10⁻⁴%)	¹⁵⁹Yb	3/2−#
¹⁶⁴Hf	72	92	163.944367(22)	111(8) s	β⁺	¹⁶⁴Lu	0+
¹⁶⁵Hf	72	93	164.94457(3)	76(4) s	β⁺	¹⁶⁵Lu	(5/2−)
¹⁶⁶Hf	72	94	165.94218(3)	6.77(30) min	β⁺	¹⁶⁶Lu	0+
¹⁶⁷Hf	72	95	166.94260(3)	2.05(5) min	β⁺	¹⁶⁷Lu	(5/2)−
¹⁶⁸Hf	72	96	167.94057(3)	25.95(20) min	β⁺	¹⁶⁸Lu	0+
¹⁶⁹Hf	72	97	168.94126(3)	3.24(4) min	β⁺	¹⁶⁹Lu	(5/2)−
¹⁷⁰Hf	72	98	169.93961(3)	16.01(13) h	EC	¹⁷⁰Lu	0+
¹⁷¹Hf	72	99	170.94049(3)	12.1(4) h	β⁺	¹⁷¹Lu	7/2(+)
^171mHf	21.93(9) keV			29.5(9) s	IT	¹⁷¹Hf	1/2(−)
¹⁷²Hf	72	100	171.939448(26)	1.87(3) y	EC	¹⁷²Lu	0+
^172mHf	2005.58(11) keV			163(3) ns			(8−)
¹⁷³Hf	72	101	172.94051(3)	23.6(1) h	β⁺	¹⁷³Lu	1/2−
¹⁷⁴Hf^{[n 9]}	72	102	173.940046(3)	7.0(12)×10¹⁶ y^[2]	α^{[n 10]}	¹⁷⁰Yb	0+	0.0016(1)	0.001619–0.001621
^174m1Hf	1549.3 keV			138(4) ns			(6+)
^174m2Hf	1797.5(20) keV			2.39(4) μs			(8−)
^174m3Hf	3311.7 keV			3.7(2) μs			(14+)
¹⁷⁵Hf	72	103	174.941509(3)	70(2) d	β⁺	¹⁷⁵Lu	5/2−
¹⁷⁶Hf^{[n 11]}	72	104	175.9414086(24)	Observationally Stable^{[n 12]}			0+	0.0526(7)	0.05206–0.05271
^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	176.9432207(23)	Observationally Stable^{[n 13]}			7/2−	0.1860(9)	0.18593–0.18606
^177m1Hf	1315.4504(8) keV			1.09(5) s			23/2+
^177m2Hf	1342.38(20) keV			55.9(12) μs			(19/2−)
^177m3Hf	2740.02(15) keV			51.4(5) min			37/2−
¹⁷⁸Hf	72	106	177.9436988(23)	Observationally Stable^{[n 14]}			0+	0.2728(7)	0.27278–0.27297
^178m1Hf	1147.423(5) keV			4.0(2) s			8−
^178m2Hf	2445.69(11) keV			31(1) y			16+
^178m3Hf	2573.5(5) keV			68(2) μs			(14−)
¹⁷⁹Hf	72	107	178.9458161(23)	Observationally Stable^{[n 15]}			9/2+	0.1362(2)	0.13619–0.1363
^179m1Hf	375.0367(25) keV			18.67(4) s			1/2−
^179m2Hf	1105.84(19) keV			25.05(25) d			25/2−
¹⁸⁰Hf	72	108	179.9465500(23)	Observationally Stable^{[n 16]}			0+	0.3508(16)	0.35076–0.351
^180m1Hf	1141.48(4) keV			5.47(4) h			8−
^180m2Hf	1374.15(4) keV			0.57(2) μs			(4−)
^180m3Hf	2425.8(10) keV			15(5) μs			(10+)
^180m4Hf	2486.3(9) keV			10(1) μs			12+
^180m5Hf	2538.3(12) keV			>10 μs			(14+)
^180m6Hf	3599.3(18) keV			90(10) μs			(18−)
¹⁸¹Hf	72	109	180.9491012(23)	42.39(6) d	β⁻	¹⁸¹Ta	1/2−
^181m1Hf	595(3) keV			80(5) μs			(9/2+)
^181m2Hf	1040(10) keV			~100 μs			(17/2+)
^181m3Hf	1738(10) keV			1.5(5) ms			(27/2−)
¹⁸²Hf	72	110	181.950554(7)	8.90(9)×10⁶ y	β⁻	¹⁸²Ta	0+
^182mHf	1172.88(18) keV			61.5(15) min	β⁻ (58%)	¹⁸²Ta	8−
^182mHf	1172.88(18) keV			61.5(15) min	IT (42%)	¹⁸²Hf	8−
¹⁸³Hf	72	111	182.95353(3)	1.067(17) h	β⁻	¹⁸³Ta	(3/2−)
¹⁸⁴Hf	72	112	183.95545(4)	4.12(5) h	β⁻	¹⁸⁴Ta	0+
^184mHf	1272.4(4) keV			48(10) s	β⁻	¹⁸⁴Ta	8−
¹⁸⁵Hf	72	113	184.95882(21)#	3.5(6) min	β⁻	¹⁸⁵Ta	3/2−#
¹⁸⁶Hf	72	114	185.96089(32)#	2.6(12) min	β⁻	¹⁸⁶Ta	0+
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)#	20# 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^[6]	72	119
¹⁹²Hf^[6]	72	120					0+
This table header & footer: view

^ ^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
^ Believed to undergo α decay to ¹⁷⁴Yb
^ Believed to undergo α decay to ¹⁷⁵Yb
^ Believed to undergo α decay to ¹⁷⁶Yb

References

^ 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 Caracciolo, V.; Nagorny, S.; Belli, P.; et al. (2020). "Search for α decay of naturally occurring Hf-nuclides using a Cs₂HfCl₆ scintillator". Nuclear Physics A. 1002 (121941): 121941. arXiv:2005.01373. Bibcode:2020NuPhA100221941C. doi:10.1016/j.nuclphysa.2020.121941. S2CID 218487451.
^ "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.
^ 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.
^ ^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.

Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

[6] Hf – Excited nuclear isomer.

[7] ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-8] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[9] Bold half-life – nearly stable, half-life longer than age of universe.

[TNN-10] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[11] Modes of decay:

EC: Electron capture

IT: Isomeric transition

[12] Bold symbol as daughter – Daughter product is stable.

[13] ( ) spin value – Indicates spin with weak assignment arguments.

[14] rimordial radionuclide

[15] Theorized to also undergo β⁺β⁺ decay to ¹⁷⁴Yb

[16] Used in lutetium-hafnium dating

[17] Believed to undergo α decay to ¹⁷²Yb

[18] Believed to undergo α decay to ¹⁷³Yb

[19] Believed to undergo α decay to ¹⁷⁴Yb

[20] Believed to undergo α decay to ¹⁷⁵Yb

[21] Believed to undergo α decay to ¹⁷⁶Yb

[NUBASE2020-1] 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.

[174Hf2020-2] Caracciolo, V.; Nagorny, S.; Belli, P.; et al. (2020). "Search for α decay of naturally occurring Hf-nuclides using a Cs₂HfCl₆ scintillator". Nuclear Physics A. 1002 (121941): 121941. arXiv:2005.01373. Bibcode:2020NuPhA100221941C. doi:10.1016/j.nuclphysa.2020.121941. S2CID 218487451.

[3] "Standard Atomic Weights: Hafnium". CIAAW. 2019.

[CIAAW2021-4] 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.

[:0-5] 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.

[PRC108-22] 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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Isotopes of hafnium

List of isotopes

References