Isotopes of holmium

Isotopes of holmium (₆₇Ho)
β−	164Er
Standard atomic weight Ar°(Ho)
	164.930329±0.000005; 164.93±0.01 (abridged);
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Natural holmium (₆₇Ho) contains one observationally stable isotope, ¹⁶⁵Ho. The below table lists 36 isotopes spanning ¹⁴⁰Ho through ¹⁷⁵Ho as well as 33 nuclear isomers. Among the known synthetic radioactive isotopes; 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 ^166m1Ho has a half-life of about 1,200 years), and most have half-lives under 3 hours.

Theoretically, the only "stable" isotope of holmium, ¹⁶⁵Ho, as well as all nuclides in the beta-decay stable isobars with mass number ≥165, can go alpha decay, hence ¹⁶⁴Dy is the heaviest theoretically stable nuclide.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 4]}	Isotopic abundance
Nuclide ^{[n 1]}	Excitation energy^{[n 4]}			Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 4]}	Isotopic abundance
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) y	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 8]}			7/2−	1.0000
¹⁶⁶Ho	67	99	165.9322842(27)	26.83(2) h	β⁻	¹⁶⁶Er	0−
^166m1Ho	5.985(18) keV			1200(180) y	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−#
This table header & footer: view

^ ^mHo – 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).
^ ^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.
^ Believed to undergo α decay to ¹⁶¹Tb

References

^ 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.
^ "Standard Atomic Weights: Holmium". CIAAW. 2021.
^ 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.

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.

[4] Ho – Excited nuclear isomer.

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

[TMS-6] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[TNN-7] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[8] Modes of decay:

EC: Electron capture

IT: Isomeric transition

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

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

[11] Believed to undergo α decay to ¹⁶¹Tb

[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.

[2] "Standard Atomic Weights: Holmium". CIAAW. 2021.

[CIAAW2021-3] 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.

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