Isotopes of hafnium

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]

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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.

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More information Nuclide, Z ...

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

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[n 1]
^mHf – Excited nuclear isomer.
[n 2]
( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
[n 3]
# – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
[n 4]
Bold half-life – nearly stable, half-life longer than age of universe.
[n 5]
# – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
[n 6]
Modes of decay:

EC: Electron capture

IT: Isomeric transition
[n 7]
Bold symbol as daughter – Daughter product is stable.
[n 8]
( ) spin value – Indicates spin with weak assignment arguments.
[n 9]
primordial radionuclide
[N 10]
Theorized to also undergo β⁺β⁺ decay to ¹⁷⁴Yb
[N 11]
Used in lutetium-hafnium dating
[N 12]
Believed to undergo α decay to ¹⁷²Yb
[N 13]
Believed to undergo α decay to ¹⁷³Yb
[N 14]
Believed to undergo α decay to ¹⁷⁴Yb
[N 15]
Believed to undergo α decay to ¹⁷⁵Yb
[N 16]
Believed to undergo α decay to ¹⁷⁶Yb

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[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.
[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.
[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]
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]
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.

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[6] [n 1]
^mHf – Excited nuclear isomer.

[7] [n 2]
( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-8] [n 3]
# – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[9] [n 4]
Bold half-life – nearly stable, half-life longer than age of universe.

[TNN-10] [n 5]
# – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[11] [n 6]
Modes of decay:

EC: Electron capture

IT: Isomeric transition

[12] [n 7]
Bold symbol as daughter – Daughter product is stable.

[13] [n 8]
( ) spin value – Indicates spin with weak assignment arguments.

[14] [n 9]
primordial radionuclide

[15] [N 10]
Theorized to also undergo β⁺β⁺ decay to ¹⁷⁴Yb

[16] [N 11]
Used in lutetium-hafnium dating

[17] [N 12]
Believed to undergo α decay to ¹⁷²Yb

[18] [N 13]
Believed to undergo α decay to ¹⁷³Yb

[19] [N 14]
Believed to undergo α decay to ¹⁷⁴Yb

[20] [N 15]
Believed to undergo α decay to ¹⁷⁵Yb

[21] [N 16]
Believed to undergo α decay to ¹⁷⁶Yb

[NUBASE2020-1] [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] [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] [3]
"Standard Atomic Weights: Hafnium". CIAAW. 2019.

[CIAAW2021-4] [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] [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] [6]
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

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