Isotopes of hafnium

Natural hafnium (Hf) 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 days. Most isotopes have half-lives under 1 minute. There are also 27 known nuclear isomers, the most stable of which is ^178m3Hf with a half-life of 31 years.

Standard atomic mass: 178.49(2) u

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life^{[n 1]}	decay mode(s)^[1]^{[n 2]}	daughter isotope(s)^{[n 3]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life^{[n 1]}	decay mode(s)^[1]^{[n 2]}	daughter isotope(s)^{[n 3]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
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) sec	β⁺	¹⁵⁴Lu	0+
¹⁵⁴Hf	72	82	153.96486(54)#	2(1) sec	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) sec	β⁺ (55%)	¹⁵⁸Lu	0+
¹⁵⁸Hf	72	86	157.954799(19)	2.84(7) sec	α (45%)	¹⁵⁴Yb	0+
¹⁵⁹Hf	72	87	158.953995(18)	5.20(10) sec	β⁺ (59%)	¹⁵⁹Lu	7/2-#
¹⁵⁹Hf	72	87	158.953995(18)	5.20(10) sec	α (41%)	¹⁵⁵Yb	7/2-#
¹⁶⁰Hf	72	88	159.950684(12)	13.6(2) sec	β⁺ (99.3%)	¹⁶⁰Lu	0+
¹⁶⁰Hf	72	88	159.950684(12)	13.6(2) sec	α (.7%)	¹⁵⁶Yb	0+
¹⁶¹Hf	72	89	160.950275(24)	18.2(5) sec	β⁺ (99.7%)	¹⁶¹Lu	3/2-#
¹⁶¹Hf	72	89	160.950275(24)	18.2(5) sec	α (.3%)	¹⁵⁷Yb	3/2-#
¹⁶²Hf	72	90	161.94721(1)	39.4(9) sec	β⁺ (99.99%)	¹⁶²Lu	0+
¹⁶²Hf	72	90	161.94721(1)	39.4(9) sec	α (.008%)	¹⁵⁸Yb	0+
¹⁶³Hf	72	91	162.94709(3)	40.0(6) sec	β⁺	¹⁶³Lu	3/2-#
¹⁶³Hf	72	91	162.94709(3)	40.0(6) sec	α (10⁻⁴%)	¹⁵⁹Yb	3/2-#
¹⁶⁴Hf	72	92	163.944367(22)	111(8) sec	β⁺	¹⁶⁴Lu	0+
¹⁶⁵Hf	72	93	164.94457(3)	76(4) sec	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) hr	EC	¹⁷⁰Lu	0+
¹⁷¹Hf	72	99	170.94049(3)	12.1(4) hr	β⁺	¹⁷¹Lu	7/2(+)
^171mHf	21.93(9) keV			29.5(9) sec	IT	¹⁷¹Hf	1/2(-)
¹⁷²Hf	72	100	171.939448(26)	1.87(3) yr	EC	¹⁷²Lu	0+
^172mHf	2005.58(11) keV			163(3) ns			(8-)
¹⁷³Hf	72	101	172.94051(3)	23.6(1) hr	β⁺	¹⁷³Lu	1/2-
¹⁷⁴Hf^{[n 4]}	72	102	173.940046(3)	2.0(4)×10¹⁵ yr	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	1797.5 keV			2.39(4) µs			(8-)
^174m4Hf	3311.7 keV			3.7(2) µs			(14+)
¹⁷⁵Hf	72	103	174.941509(3)	70(2) days	β⁺	¹⁷⁵Lu	5/2-
¹⁷⁶Hf^{[n 5]}	72	104	175.9414086(24)	Observationally Stable^{[n 6]}			0+	0.0526(7)	0.05206-0.05271
¹⁷⁷Hf	72	105	176.9432207(23)	Observationally Stable^{[n 7]}			7/2-	0.1860(9)	0.18593-0.18606
^177m1Hf	1315.4504(8) keV			1.09(5) sec			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 8]}			0+	0.2728(7)	0.27278-0.27297
^178m1Hf	1147.423(5) keV			4.0(2) sec			8-
^178m2Hf	2573.5(5) keV			68(2) µs			(14-)
^178m3Hf	2445.69(11) keV			31(1) yr			16+
¹⁷⁹Hf	72	107	178.9458161(23)	Observationally Stable^{[n 9]}			9/2+	0.1362(2)	0.13619-0.1363
^179m1Hf	375.0367(25) keV			18.67(4) sec			1/2-
^179m2Hf	1105.84(19) keV			25.05(25) days			25/2-
¹⁸⁰Hf	72	108	179.9465500(23)	Observationally Stable^{[n 10]}			0+	0.3508(16)	0.35076-0.351
^180m1Hf	1141.48(4) keV			5.47(4) hr			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) days	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 yr	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) hr	β^-	¹⁸³Ta	(3/2-)
¹⁸⁴Hf	72	112	183.95545(4)	4.12(5) hr	β^-	¹⁸⁴Ta	0+
^184mHf	1272.4(4) keV			48(10) sec	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+

^ Bold for isotopes with half-lives longer than the age of the universe (nearly stable)
^ Abbreviations:
EC: Electron capture
IT: Isomeric transition
^ Bold for stable isotopes
^ 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

Notes

Evaluated isotopic composition is for most but not all commercial samples.
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References

^ http://www.nucleonica.net/unc.aspx

Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683. http://www.iupac.org/publications/pac/75/6/0683/pdf/.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. http://iupac.org/publications/pac/78/11/2051/pdf/. Lay summary.
Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/. Retrieved September 2005.
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0849304859.

Isotopes of lutetium	Isotopes of hafnium	Isotopes of tantalum
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