Isotopes of hafnium

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

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] The next most stable radioisotope is ¹⁸²Hf with a half-life of 8.90 million years, an extinct radionuclide used in hafnium–tungsten dating to study the chronology of planetary differentiation.^[6]

Other isotopes have been synthesized running from ¹⁵³Hf to ¹⁹²Hf, but none of the 33 others has a half-life over 1.87 years, and most have half-lives under five minutes. There are also at least 41 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)^[7] ^{[n 2]}^{[n 3]}	Discovery year^[8]^[9]	Half-life^[1] ^{[n 4]}^{[n 5]}	Decay mode^[1] ^{[n 6]}	Daughter isotope ^{[n 7]}	Spin and parity^[1] ^{[n 8]}^{[n 5]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy^{[n 5]}			Discovery year^[8]^[9]	Half-life^[1] ^{[n 4]}^{[n 5]}	Decay mode^[1] ^{[n 6]}	Daughter isotope ^{[n 7]}	Spin and parity^[1] ^{[n 8]}^{[n 5]}	Normal proportion^[1]	Range of variation
¹⁵³Hf	72	81	152.970692(322)#	(2000)	400# ms [>200 ns]	β⁺?	¹⁵³Lu	1/2+#
¹⁵⁴Hf	72	82	153.96486(32)#	1981	2(1) s	β⁺	¹⁵⁴Lu	0+
¹⁵⁴Hf	72	82	153.96486(32)#	1981	2(1) s	α (rare)	¹⁵⁰Yb	0+
^154mHf	2721(50)# keV			1989	9(4) μs	IT	¹⁵⁴Hf	(10+)
¹⁵⁵Hf	72	83	154.96317(32)#	1981	843(30) ms	β⁺	¹⁵⁵Lu	7/2−#
¹⁵⁶Hf	72	84	155.95940(16)	1979	23(1) ms	α	¹⁵²Yb	0+
^156mHf	1958.8(10) keV			1989	480(40) μs	α	¹⁵²Yb	(8+)
¹⁵⁷Hf	72	85	156.95829(22)#	1965	115(1) ms	α (94%)	¹⁵³Yb	7/2−
¹⁵⁷Hf	72	85	156.95829(22)#	1965	115(1) ms	β⁺ (6%)	¹⁵⁷Lu	7/2−
¹⁵⁸Hf	72	86	157.954801(19)	1965	2.85(7) s	β⁺ (55.7%)	¹⁵⁸Lu	0+
¹⁵⁸Hf	72	86	157.954801(19)	1965	2.85(7) s	α (44.3%)	¹⁵⁴Yb	0+
¹⁵⁹Hf	72	87	158.953996(18)	1973	5.20(10) s	β⁺ (65%)	¹⁵⁹Lu	7/2−
¹⁵⁹Hf	72	87	158.953996(18)	1973	5.20(10) s	α (35%)	¹⁵⁵Yb	7/2−
¹⁶⁰Hf	72	88	159.950683(10)	1973	13.6(2) s	β⁺ (99.3%)	¹⁶⁰Lu	0+
¹⁶⁰Hf	72	88	159.950683(10)	1973	13.6(2) s	α (0.7%)	¹⁵⁶Yb	0+
¹⁶¹Hf	72	89	160.950278(25)	1973	18.4(4) s	β⁺ (99.71%)	¹⁶¹Lu	(7/2−)
¹⁶¹Hf	72	89	160.950278(25)	1973	18.4(4) s	α (0.29%)	¹⁵⁷Yb	(7/2−)
^161mHf	329.0(5) keV			2014	4.8(2) μs	IT	¹⁶¹Hf	(13/2+)
¹⁶²Hf	72	90	161.9472155(96)	1982	39.4(9) s	β⁺ (99.99%)	¹⁶²Lu	0+
¹⁶²Hf	72	90	161.9472155(96)	1982	39.4(9) s	α (0.008%)	¹⁵⁸Yb	0+
¹⁶³Hf	72	91	162.947107(28)	1982	40.0(6) s	β⁺	¹⁶³Lu	(5/2−)
¹⁶⁴Hf	72	92	163.944371(17)	1981	111(8) s	β⁺	¹⁶⁴Lu	0+
¹⁶⁵Hf	72	93	164.944567(30)	1981	76(4) s	β⁺	¹⁶⁵Lu	(5/2−)
¹⁶⁶Hf	72	94	165.942180(30)	1965	6.77(30) min	β⁺	¹⁶⁶Lu	0+
¹⁶⁷Hf	72	95	166.942600(30)	1969	2.05(5) min	β⁺	¹⁶⁷Lu	(5/2)−
¹⁶⁸Hf	72	96	167.940568(30)	1961	25.95(20) min	EC (98%)	¹⁶⁸Lu	0+
¹⁶⁸Hf	72	96	167.940568(30)	1961	25.95(20) min	β⁺ (2%)	¹⁶⁸Lu	0+
¹⁶⁹Hf	72	97	168.941259(30)	1969	3.24(4) min	β⁺	¹⁶⁹Lu	(5/2−)
¹⁷⁰Hf	72	98	169.939609(30)	1961	16.01(13) h	EC	¹⁷⁰Lu	0+
¹⁷¹Hf	72	99	170.940492(31)	1951	12.1(4) h	β⁺	¹⁷¹Lu	7/2+
^171mHf	21.93(9) keV			1997	29.5(9) s	IT	¹⁷¹Hf	1/2−
¹⁷²Hf	72	100	171.939450(26)	1951	1.87(3) y	EC	¹⁷²Lu	0+
^172mHf	2005.84(11) keV			1977	163(3) ns	IT	¹⁷²Hf	(8−)
¹⁷³Hf	72	101	172.940513(30)	1951	23.6(1) h	β⁺	¹⁷³Lu	1/2−
^173m1Hf	107.16(5) keV			1973	180(8) ns	IT	¹⁷³Hf	5/2−
^173m2Hf	197.47(10) keV			1973	160(40) ns	IT	¹⁷³Hf	7/2+
¹⁷⁴Hf^{[n 9]}	72	102	173.9400484(24)	1939	3.8+1.7 −0.9×10¹⁶ y^[2]	α^{[n 10]}	¹⁷⁰Yb	0+	0.0016(12)
^174m1Hf	1549.26(4) keV			1973	138(4) ns	IT	¹⁷⁴Hf	6+
^174m2Hf	1797.59(7) keV			1990	2.39(4) μs	IT	¹⁷⁴Hf	8−
^174m3Hf	3312.07(6) keV			1990	3.7(2) μs	IT	¹⁷⁴Hf	14+
¹⁷⁵Hf	72	103	174.9415114(25)	1949	69.90(7) d^[3]	EC	¹⁷⁵Lu	5/2−
^175m1Hf	125.89(12) keV			1964	53.7(15) μs	IT	¹⁷⁵Hf	1/2−
^175m2Hf	1433.41(12) keV			1980	1.10(8) μs	IT	¹⁷⁵Hf	19/2+
^175m3Hf	3015.6(4) keV			1980	1.21(15) μs	IT	¹⁷⁵Hf	35/2−
^175m4Hf	4636.2(12) keV			1990	1.9(1) μs	IT	¹⁷⁵Hf	45/2+
¹⁷⁶Hf^{[n 11]}	72	104	175.9414098(16)	1934	Observationally Stable^{[n 12]}			0+	0.0526(70)
^176m1Hf	1333.07(7) keV			1964	9.6(3) μs	IT	¹⁷⁶Hf	6+
^176m2Hf	1559.31(9) keV			1967	9.9(2) μs	IT	¹⁷⁶Hf	8−
^176m3Hf	2865.8(7) keV			1975	401(6) μs	IT	¹⁷⁶Hf	14−
^176m4Hf	4863.6(9) keV			1976	43(4) μs	IT	¹⁷⁶Hf	22−
¹⁷⁷Hf	72	105	176.9432302(15)	1934	Observationally Stable^{[n 13]}			7/2−	0.1860(16)
^177m1Hf	1315.4502(8) keV			1966	1.09(5) s	IT	¹⁷⁷Hf	23/2+
^177m2Hf	1342.4(10) keV			1998	55.9(12) μs	IT	¹⁷⁷Hf	(19/2−)
^177m3Hf	2740.02(15) keV			1971	51.4(5) min	IT	¹⁷⁷Hf	37/2−
¹⁷⁸Hf	72	106	177.9437083(15)	1934	Observationally Stable^{[n 14]}			0+	0.2728(28)
^178m1Hf	1147.416(6) keV			1958	4.0(2) s	IT	¹⁷⁸Hf	8−
^178m2Hf	2446.09(8) keV			1968	31(1) y	IT	¹⁷⁸Hf	16+
^178m3Hf	2572.4(3) keV			1977	68(2) μs	IT	¹⁷⁸Hf	14−
¹⁷⁹Hf	72	107	178.9458257(15)	1934	Observationally Stable^{[n 15]}			9/2+	0.1362(11)
^179m1Hf	375.0352(25) keV			1951	18.67(4) s	IT	¹⁷⁹Hf	1/2−
^179m2Hf	1106.412(33) keV			1970	25.00(17) d	IT	¹⁷⁹Hf	25/2−
^179m3Hf	3775.2(21) keV			2000	15(5) μs	IT	¹⁷⁹Hf	(43/2+)
¹⁸⁰Hf	72	108	179.9465595(15)	1934	Observationally Stable^{[n 16]}			0+	0.3508(33)
^180m1Hf	1141.552(15) keV			1951	5.53(2) h	IT (99.69%)	¹⁸⁰Hf	8−
^180m1Hf	1141.552(15) keV			1951	5.53(2) h	β⁻ (0.31%)	^180m1Ta^[10]	8−
^180m2Hf	1374.36(4) keV			2016	570(20) ns	IT	¹⁸⁰Hf	4−
^180m3Hf	2485.5(5) keV			2016	0.94(11) μs	IT	¹⁸⁰Hf	12+
^180m4Hf	3599.0(10) keV			1999	90(10) μs	IT	¹⁸⁰Hf	(18−)
¹⁸¹Hf	72	109	180.9491108(15)	1935	42.39(6) d	β⁻	¹⁸¹Ta	1/2−
^181m1Hf	595.27(4) keV			1999	80(5) μs	IT	¹⁸¹Hf	(9/2+)
^181m2Hf	1043.5(8) keV			2001	~100 μs	IT	¹⁸¹Hf	(17/2+)
^181m3Hf	1741.9(13) keV			2001	1.5(5) ms	IT	¹⁸¹Hf	(25/2−)
¹⁸²Hf^{[n 17]}	72	110	181.9505637(66)	1961	8.90(9)×10⁶ y	β⁻	¹⁸²Ta	0+
^182m1Hf	1172.87(18) keV			1971	61.5(15) min	β⁻ (54%)	¹⁸²Ta	8−
^182m1Hf	1172.87(18) keV			1971	61.5(15) min	IT (46%)	¹⁸²Hf	8−
^182m2Hf	2571.3(12) keV			1999	40(10) μs	IT	¹⁸²Hf	(13+)
¹⁸³Hf	72	111	182.953533(32)	1956	1.018(2) h	β⁻	¹⁸³Ta	(3/2−)
^183mHf	1464(64) keV			2010	40(30) s	IT	¹⁸³Hf	27/2−#
¹⁸⁴Hf	72	112	183.955449(43)	1973	4.12(5) h	β⁻	¹⁸⁴Ta	0+
^184m1Hf	1272.2(4) keV			1995	48(10) s	IT	¹⁸⁴Hf	8−
^184m2Hf	2477(10) keV			2010	16(7) min			15+#
¹⁸⁵Hf	72	113	184.958862(69)	1993	3.5(6) min	β⁻	¹⁸⁵Ta	(9/2−)
¹⁸⁶Hf	72	114	185.960897(55)	1998	2.6(12) min	β⁻	¹⁸⁶Ta	0+
^186mHf	2968(43) keV			2010	>20 s			17+#
¹⁸⁷Hf	72	115	186.96457(22)#	1999	14# s [>300 ns]			9/2−#
^187mHf	500(300)# keV			2009	270(80) ns	IT	¹⁸⁷Hf	3/2−#
¹⁸⁸Hf	72	116	187.96690(32)#	1999	7# s [>300 ns]			0+
¹⁸⁹Hf	72	117	188.97085(32)#	2009	400# ms [>300 ns]			3/2−#
¹⁹⁰Hf	72	118	189.97338(43)#	2012	600# ms [>300 ns]			0+
¹⁹¹Hf^[11]	72	119		2023
¹⁹²Hf^[11]	72	120		2023				0+
This table header & footer:

^ ^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 with a half-life over 1.3×10¹⁸ y.
^ Believed to undergo α decay to ¹⁷⁴Yb
^ Believed to undergo α decay to ¹⁷⁵Yb
^ Believed to undergo α decay to ¹⁷⁶Yb
^ Extinct radionuclide, used in hafnium–tungsten dating^[6]

References

^ ^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.
^ ^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.
^ ^a ^b Kmak, K. N.; Neupane, S.; Kolos, K.; et al. (2025). "Measurement of the ¹⁷⁵Hf half-life". Physical Review C. 111 (024308). doi:10.1103/PhysRevC.111.024308.
^ "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.
^ ^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.
^ 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.
^ FRIB Nuclear Data Group. "Discovery of Nuclides Project, Isotope Database". doi:10.11578/frib/2279152.
^ FRIB Nuclear Data Group. "Discovery of Nuclides Project, Isomer Database". doi:10.11578/frib/2572219.
^ McCutchan, E.A. (May 2015). "Nuclear Data Sheets for A = 180". Nuclear Data Sheets. 126: 151–372. Bibcode:2015NDS...126..151M. doi:10.1016/j.nds.2015.05.002. OSTI 1467505.
^ ^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. OSTI 1998848. S2CID 261649436.

[7] Hf – Excited nuclear isomer.

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

[TMS-10] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

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

[TNN-14] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[15] Modes of decay:

EC: Electron capture

IT: Isomeric transition

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

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

[18] rimordial radionuclide

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

[20] Used in lutetium-hafnium dating

[21] Believed to undergo α decay to ¹⁷²Yb

[22] Believed to undergo α decay to ¹⁷³Yb with a half-life over 1.3×10¹⁸ y.

[23] Believed to undergo α decay to ¹⁷⁴Yb

[24] Believed to undergo α decay to ¹⁷⁵Yb

[25] Believed to undergo α decay to ¹⁷⁶Yb

[27] Extinct radionuclide, used in hafnium–tungsten dating^[6]

[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.

[belli2024-2] 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.

[175Hf-2025-3] Kmak, K. N.; Neupane, S.; Kolos, K.; et al. (2025). "Measurement of the ¹⁷⁵Hf half-life". Physical Review C. 111 (024308). doi:10.1103/PhysRevC.111.024308.

[CIAAWhafnium-4] "Standard Atomic Weights: Hafnium". CIAAW. 2019.

[CIAAW2021-5] 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.

[:0-6] 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.

[AME2020_II-8] 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.

[IsotopeFRIB-11] FRIB Nuclear Data Group. "Discovery of Nuclides Project, Isotope Database". doi:10.11578/frib/2279152.

[IsomerFRIB-12] FRIB Nuclear Data Group. "Discovery of Nuclides Project, Isomer Database". doi:10.11578/frib/2572219.

[26] McCutchan, E.A. (May 2015). "Nuclear Data Sheets for A = 180". Nuclear Data Sheets. 126: 151–372. Bibcode:2015NDS...126..151M. doi:10.1016/j.nds.2015.05.002. OSTI 1467505.

[PRC108-28] 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. OSTI 1998848. S2CID 261649436.

[1]

[2]

[3]

[4]

[5]

[6]

[n 1]

[7]

[n 2]

[n 3]

[8]

[9]

[n 4]

[n 5]

[n 6]

[n 7]

[n 8]

[n 9]

[n 10]

[n 11]

[n 12]

[n 13]

[n 14]

[n 15]

[n 16]

[10]

[n 17]

[11]

EC:	Electron capture
IT:	Isomeric transition

List of isotopes

See also

References