Isotopes of holmium

Natural holmium (Ho) contains one stable isotope, ¹⁶⁵Ho. A number of synthetic radioactive isotopes are known, the most stable one is ¹⁶³Ho, with a half-life of 4,570 years. All other radioisotopes have half-lives not greater than 1.117 days in their ground states (although the metastable ^166mHo has a half-life of about 1,200 years), and most have half-lives under 3 hours.

Standard atomic mass: 164.93032(2) u

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)^[1]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life	decay mode(s)^[1]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
¹⁴⁰Ho	67	73	139.96854(54)#	6(3) ms			8+#
¹⁴¹Ho	67	74	140.96310(54)#	4.1(3) ms			(7/2-)
^141mHo	66(2) keV			6.4(8) µs			(1/2+)
¹⁴²Ho	67	75	141.95977(54)#	400(100) ms	β⁺	¹⁴²Dy	(6 to 9)
¹⁴²Ho	67	75	141.95977(54)#	400(100) ms	p	¹⁴¹Dy	(6 to 9)
¹⁴³Ho	67	76	142.95461(43)#	300# ms [>200 ns]	β⁺	¹⁴³Dy	11/2-#
¹⁴⁴Ho	67	77	143.95148(32)#	0.7(1) s	β⁺	¹⁴⁴Dy
¹⁴⁴Ho	67	77	143.95148(32)#	0.7(1) s	β⁺, p	¹⁴³Tb
¹⁴⁵Ho	67	78	144.94720(32)#	2.4(1) s	β⁺	¹⁴⁵Dy	(11/2-)
^145mHo	100(100)# keV			100# ms			5/2+#
¹⁴⁶Ho	67	79	145.94464(21)#	3.6(3) s	β⁺	¹⁴⁶Dy	(10+)
¹⁴⁶Ho	67	79	145.94464(21)#	3.6(3) s	β⁺, p (rare)	¹⁴⁵Tb	(10+)
¹⁴⁷Ho	67	80	146.94006(3)	5.8(4) s	β⁺	¹⁴⁷Dy	(11/2-)
¹⁴⁷Ho	67	80	146.94006(3)	5.8(4) s	β⁺, p (rare)	¹⁴⁶Tb	(11/2-)
¹⁴⁸Ho	67	81	147.93772(14)	2.2(11) s	β⁺	¹⁴⁸Dy	(1+)
^148m1Ho	400(100)# keV			9.49(12) s	β⁺ (99.92%)	¹⁴⁸Dy	(6)-
^148m1Ho	400(100)# keV			9.49(12) s	β⁺, p (.08%)	¹⁴⁷Tb	(6)-
^148m2Ho	690(100)# keV			2.35(4) ms			(10+)
¹⁴⁹Ho	67	82	148.933775(20)	21.1(2) s	β⁺	¹⁴⁹Dy	(11/2-)
^149m1Ho	48.80(20) keV			56(3) s	β⁺	¹⁴⁹Dy	(1/2+)
^149m2Ho	7200(350) keV			>=100 ns
¹⁵⁰Ho	67	83	149.933496(15)	76.8(18) s	β⁺	¹⁵⁰Dy	2-
^150m1Ho	-10(50) keV			23.3(3) s	β⁺	¹⁵⁰Dy	(9)+
^150m2Ho	~8000 keV			751 ns
¹⁵¹Ho	67	84	150.931688(13)	35.2(1) s	β⁺ (78%)	¹⁵¹Dy	11/2(-)
¹⁵¹Ho	67	84	150.931688(13)	35.2(1) s	α (22%)	¹⁴⁷Tb	11/2(-)
^151mHo	41.0(2) keV			47.2(10) s	α (77%)	¹⁴⁷Tb	1/2(+)
^151mHo	41.0(2) keV			47.2(10) s	β⁺ (22%)	¹⁵¹Dy	1/2(+)
¹⁵²Ho	67	85	151.931714(15)	161.8(3) s	β⁺ (88%)	¹⁵²Dy	2-
¹⁵²Ho	67	85	151.931714(15)	161.8(3) s	α (12%)	¹⁴⁸Tb	2-
^152m1Ho	160(1) keV			50.0(4) s			9+
^152m2Ho	3019.59(19) keV			8.4(3) µs			19-
¹⁵³Ho	67	86	152.930199(6)	2.01(3) min	β⁺ (99.94%)	¹⁵³Dy	11/2-
¹⁵³Ho	67	86	152.930199(6)	2.01(3) min	α (.05%)	¹⁴⁹Tb	11/2-
^153m1Ho	68.7(3) keV			9.3(5) min	β⁺ (99.82%)	¹⁵³Dy	1/2+
^153m1Ho	68.7(3) keV			9.3(5) min	α (.18%)	¹⁴⁹Tb	1/2+
^153m2Ho	2772 keV			229(2) ns			(31/2+)
¹⁵⁴Ho	67	87	153.930602(9)	11.76(19) min	β⁺ (99.98%)	¹⁵⁴Dy	2-
¹⁵⁴Ho	67	87	153.930602(9)	11.76(19) min	α (.02%)	¹⁵⁰Tb	2-
^154mHo	238(30) keV			3.10(14) min	β⁺ (99.99%)	¹⁵⁴Dy	8+
					α (.001%)	¹⁵⁰Tb
					IT (rare)	¹⁵⁴Ho
¹⁵⁵Ho	67	88	154.929103(19)	48(1) min	β⁺	¹⁵⁵Dy	5/2+
^155mHo	141.97(11) keV			880(80) µs			11/2-
¹⁵⁶Ho	67	89	155.92984(5)	56(1) min	β⁺	¹⁵⁶Dy	4-
^156m1Ho	100(50)# keV			7.8(3) min	β⁺	¹⁵⁶Dy	(9+)
^156m1Ho	100(50)# keV			7.8(3) min	IT	¹⁵⁶Ho	(9+)
^156m2Ho	52.4(5) keV			9.5(15) s			1-
¹⁵⁷Ho	67	90	156.928256(26)	12.6(2) min	β⁺	¹⁵⁷Dy	7/2-
¹⁵⁸Ho	67	91	157.928941(29)	11.3(4) min	β⁺ (93%)	¹⁵⁸Dy	5+
¹⁵⁸Ho	67	91	157.928941(29)	11.3(4) min	α (7%)	¹⁵⁴Tb	5+
^158m1Ho	67.200(10) keV			28(2) min	IT (81%)	¹⁵⁸Ho	2-
^158m1Ho	67.200(10) keV			28(2) min	β⁺ (19%)	¹⁵⁸Dy	2-
^158m2Ho	180(70)# keV			21.3(23) min			(9+)
¹⁵⁹Ho	67	92	158.927712(4)	33.05(11) min	β⁺	¹⁵⁹Dy	7/2-
^159mHo	205.91(5) keV			8.30(8) s	IT	¹⁵⁹Ho	1/2+
¹⁶⁰Ho	67	93	159.928729(16)	25.6(3) min	β⁺	¹⁶⁰Dy	5+
^160m1Ho	59.98(3) keV			5.02(5) h	IT (65%)	¹⁶⁰Ho	2-
^160m1Ho	59.98(3) keV			5.02(5) h	β⁺ (35%)	¹⁶⁰Dy	2-
^160m2Ho	197(16) keV			3 s			(9+)
¹⁶¹Ho	67	94	160.927855(3)	2.48(5) h	EC	¹⁶¹Dy	7/2-
^161mHo	211.16(3) keV			6.76(7) s	IT	¹⁶¹Ho	1/2+
¹⁶²Ho	67	95	161.929096(4)	15.0(10) min	β⁺	¹⁶²Dy	1+
^162mHo	106(7) keV			67.0(7) min	IT (62%)	¹⁶²Ho	6-
^162mHo	106(7) keV			67.0(7) min	β⁺ (38%)	¹⁶²Dy	6-
¹⁶³Ho	67	96	162.9287339(27)	4570(25) a	EC	¹⁶³Dy	7/2-
^163mHo	297.88(7) keV			1.09(3) s	IT	¹⁶³Ho	1/2+
¹⁶⁴Ho	67	97	163.9302335(30)	29(1) min	EC (60%)	¹⁶⁴Dy	1+
¹⁶⁴Ho	67	97	163.9302335(30)	29(1) min	β^- (40%)	¹⁶⁴Er	1+
^164mHo	139.77(8) keV			38.0(10) min [37.5(+15-5) min]	IT	¹⁶⁴Ho	6-
¹⁶⁵Ho	67	98	164.9303221(27)	Observationally Stable^{[n 3]}			7/2-	1.0000
¹⁶⁶Ho	67	99	165.9322842(27)	26.83(2) h	β^-	¹⁶⁶Er	0-
^166m1Ho	5.985(18) keV			1,200(180) a	β^-	¹⁶⁶Er	(7)-
^166m2Ho	190.9052(20) keV			185(15) µs			3+
¹⁶⁷Ho	67	100	166.933133(6)	3.003(18) h	β^-	¹⁶⁷Er	7/2-
^167mHo	259.34(11) keV			6.0(10) µs			3/2+
¹⁶⁸Ho	67	101	167.93552(3)	2.99(7) min	β^-	¹⁶⁸Er	3+
^168m1Ho	59(1) keV			132(4) s	IT (99.5%)	¹⁶⁸Ho	(6+)
^168m1Ho	59(1) keV			132(4) s	β^- (.5%)	¹⁶⁸Er	(6+)
^168m2Ho	143.4(2) keV			>4 µs			(1)-
^168m3Ho	192.6(2) keV			108(11) ns			1+
¹⁶⁹Ho	67	102	168.936872(22)	4.72(10) min	β^-	¹⁶⁹Er	7/2-
¹⁷⁰Ho	67	103	169.93962(5)	2.76(5) min	β^-	¹⁷⁰Er	6+#
^170mHo	120(70) keV			43(2) s	β^-	¹⁷⁰Er	(1+)
¹⁷¹Ho	67	104	170.94147(64)	53(2) s	β^-	¹⁷¹Er	7/2-#
¹⁷²Ho	67	105	171.94482(43)#	25(3) s	β^-	¹⁷²Er
¹⁷³Ho	67	106	172.94729(43)#	10# s	β^-	¹⁷³Er	7/2-#
¹⁷⁴Ho	67	107	173.95115(54)#	8# s
¹⁷⁵Ho	67	108	174.95405(64)#	5# s			7/2-#

^ Abbreviations:
EC: Electron capture
IT: Isomeric transition
^ Bold for stable isotopes
^ Believed to undergo α decay to ¹⁶¹Tb

Notes

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.

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