Isotopes of hafnium

Natural hafnium (₇₂Hf) consists of five stable isotopes (¹⁷⁶Hf, ¹⁷⁷Hf, ¹⁷⁸Hf, ¹⁷⁹Hf, and ¹⁸⁰Hf) and one very long-lived radioisotope, ¹⁷⁴Hf, with a half-life of 2×10¹⁵ years. In addition, there are 30 other known radionuclides, the most stable of which is ¹⁸²Hf with a half-life of 8.9×10⁶ years. 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 isomers, the most stable of which is ^178m2Hf with a half-life of 31 years.

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)	2.0(4)×10¹⁵ y	α	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 10]	72	104	175.9414086(24)	Observationally Stable[n 11]			0+	0.0526(7)	0.05206–0.05271
¹⁷⁷Hf	72	105	176.9432207(23)	Observationally Stable[n 12]			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 13]			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 14]			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 15]			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	186.96459(43)#	30# s [>300 ns]
¹⁸⁸Hf	72	116	187.96685(54)#	20# s [>300 ns]			0+

^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.
# – 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
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

Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

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. Lay summary.
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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[2] Hf – Excited nuclear isomer.

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

[TMS-4] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

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

[TNN-6] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[7] Modes of decay:

EC: Electron capture

IT: Isomeric transition

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

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

[10] rimordial radionuclide

[11] Used in lutetium-hafnium dating

[12] Believed to undergo α decay to ¹⁷²Yb

[13] Believed to undergo α decay to ¹⁷³Yb

[14] Believed to undergo α decay to ¹⁷⁴Yb

[15] Believed to undergo α decay to ¹⁷⁵Yb

[16] Believed to undergo α decay to ¹⁷⁶Yb

[CIAAW2013-1] Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

EC:	Electron capture
IT:	Isomeric transition