Isotopes of thulium

Naturally occurring thulium (Tm) is composed of 1 stable isotope, ¹⁶⁹Tm (100% natural abundance). 34 radioisotopes have been characterized, with the most stable being ¹⁷¹Tm with a half-life of 1.92 years, ¹⁷⁰Tm with a half-life of 128.6 days, ¹⁶⁸Tm with a half-life of 93.1 days, and ¹⁶⁷Tm with a half-life of 9.25 days. All of the remaining radioactive isotopes have half-lives that are less than 64 hours, and the majority of these have half-lives that are less than 2 minutes. This element also has 26 meta states, with the most stable being ^164mTm (t_1/2 5.1 minutes), ^160mTm (t_1/2 74.5 seconds) and ^155mTm (t_1/2 45 seconds).

The isotopes of thulium range in atomic weight from 144.97007 u (¹⁴⁵Tm) to 178.95534 u (¹⁷⁹Tm). The primary decay mode before the most abundant stable isotope, ¹⁶⁹Tm, is electron capture, and the primary mode after is beta emission. The primary decay products before ¹⁶⁹Tm are erbium isotopes, and the primary products after are ytterbium isotopes.

Standard atomic mass: 168.93421(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)
¹⁴⁵Tm	69	76	144.97007(43)#	3.1(3) µs			(11/2-)
¹⁴⁶Tm	69	77	145.96643(43)#	240(30) ms	p	¹⁴⁵Er	(6-)
¹⁴⁶Tm	69	77	145.96643(43)#	240(30) ms	β⁺ (rare)	¹⁴⁶Er	(6-)
^146mTm	71(6) keV			72(23) ms	p	¹⁴⁵Er	(10+)
^146mTm	71(6) keV			72(23) ms	β⁺ (rare)	¹⁴⁶Er	(10+)
¹⁴⁷Tm	69	78	146.96096(32)#	0.58(3) s	β⁺ (85%)	¹⁴⁷Er	11/2-
¹⁴⁷Tm	69	78	146.96096(32)#	0.58(3) s	p (15%)	¹⁴⁶Er	11/2-
^147mTm	60(5) keV			360(40) µs			3/2+
¹⁴⁸Tm	69	79	147.95784(43)#	0.7(2) s	β⁺	¹⁴⁸Er	(10+)
^148mTm				0.7 s
¹⁴⁹Tm	69	80	148.95272(32)#	0.9(2) s	β⁺ (99.74%)	¹⁴⁹Er	(11/2-)
¹⁴⁹Tm	69	80	148.95272(32)#	0.9(2) s	β⁺, p (.26%)	¹⁴⁸Ho	(11/2-)
¹⁵⁰Tm	69	81	149.94996(21)#	3# s	β⁺	¹⁵⁰Er	(1+)
^150m1Tm	140(140)# keV			2.20(6) s	β⁺ (98.8%)	¹⁵⁰Er	(6-)
^150m1Tm	140(140)# keV			2.20(6) s	β⁺, p (1.2%)	¹⁴⁹Ho	(6-)
^150m2Tm	810(140)# keV			5.2(3) ms			(10+)
¹⁵¹Tm	69	82	150.945483(22)	4.17(10) s	β⁺	¹⁵¹Er	(11/2-)
^151m1Tm	92(7) keV			6.6(14) s	β⁺	¹⁵¹Er	(1/2+)
^151m2Tm	2655.67(22) keV			451(24) ns			(27/2-)
¹⁵²Tm	69	83	151.94442(8)	8.0(10) s	β⁺	¹⁵²Er	(2#)-
^152m1Tm	100(80)# keV			5.2(6) s	β⁺	¹⁵²Er	(9)+
^152m2Tm	2555.05(19)+X keV			294(12) ns			(17+)
¹⁵³Tm	69	84	152.942012(20)	1.48(1) s	α (91%)	¹⁴⁹Ho	(11/2-)
¹⁵³Tm	69	84	152.942012(20)	1.48(1) s	β⁺ (9%)	¹⁵³Er	(11/2-)
^153mTm	43.2(2) keV			2.5(2) s	α (92%)	¹⁴⁹Ho	(1/2+)
^153mTm	43.2(2) keV			2.5(2) s	β⁺ (8%)	¹⁵³Er	(1/2+)
¹⁵⁴Tm	69	85	153.941568(15)	8.1(3) s	β⁺ (56%)	¹⁵⁴Er	(2-)
¹⁵⁴Tm	69	85	153.941568(15)	8.1(3) s	α (44%)	¹⁵⁰Ho	(2-)
^154mTm	70(50) keV			3.30(7) s	α (90%)	¹⁵⁰Ho	(9+)
^154mTm	70(50) keV			3.30(7) s	β⁺ (10%)	¹⁵⁴Er	(9+)
¹⁵⁵Tm	69	86	154.939199(14)	21.6(2) s	β⁺ (98.1%)	¹⁵⁵Er	(11/2-)
¹⁵⁵Tm	69	86	154.939199(14)	21.6(2) s	α (1.9%)	¹⁵¹Ho	(11/2-)
^155mTm	41(6) keV			45(3) s	β⁺ (92%)	¹⁵⁵Er	(1/2+)
^155mTm	41(6) keV			45(3) s	α (8%)	¹⁵¹Ho	(1/2+)
¹⁵⁶Tm	69	87	155.938980(17)	83.8(18) s	β⁺ (99.93%)	¹⁵⁶Er	2-
¹⁵⁶Tm	69	87	155.938980(17)	83.8(18) s	α (.064%)	¹⁵²Er	2-
^156mTm	203.6(5) keV			~400 ns			(11-)
¹⁵⁷Tm	69	88	156.93697(3)	3.63(9) min	β⁺	¹⁵⁷Er	1/2+
¹⁵⁸Tm	69	89	157.936980(27)	3.98(6) min	β⁺	¹⁵⁸Er	2-
^158mTm	50(100)# keV			~20 ns			(5+)
¹⁵⁹Tm	69	90	158.93498(3)	9.13(16) min	β⁺	¹⁵⁹Er	5/2+
¹⁶⁰Tm	69	91	159.93526(4)	9.4(3) min	β⁺	¹⁶⁰Er	1-
^160m1Tm	70(20) keV			74.5(15) s	IT (85%)	¹⁶⁰Tm	5(+#)
^160m1Tm	70(20) keV			74.5(15) s	β⁺ (15%)	¹⁶⁰Er	5(+#)
^160m2Tm	98.2+X keV			~200 ns			(8)
¹⁶¹Tm	69	92	160.93355(3)	30.2(8) min	β⁺	¹⁶¹Er	7/2+
^161m1Tm	7.4(2) keV			5# min			1/2+
^161m2Tm	78.20(3) keV			110(3) ns			7/2-
¹⁶²Tm	69	93	161.933995(28)	21.70(19) min	β⁺	¹⁶²Er	1-
^162mTm	130(40) keV			24.3(17) s	IT (82%)	¹⁶²Tm	5+
^162mTm	130(40) keV			24.3(17) s	β⁺ (18%)	¹⁶²Er	5+
¹⁶³Tm	69	94	162.932651(6)	1.810(5) h	β⁺	¹⁶³Er	1/2+
¹⁶⁴Tm	69	95	163.93356(3)	2.0(1) min	β⁺	¹⁶⁴Er	1+
^164mTm	10(6) keV			5.1(1) min	IT (80%)	¹⁶⁴Tm	6-
^164mTm	10(6) keV			5.1(1) min	β⁺ (20%)	¹⁶⁴Er	6-
¹⁶⁵Tm	69	96	164.932435(4)	30.06(3) h	β⁺	¹⁶⁵Er	1/2+
¹⁶⁶Tm	69	97	165.933554(13)	7.70(3) h	β⁺	¹⁶⁶Er	2+
^166mTm	122(8) keV			340(25) ms	IT	¹⁶⁶Tm	6-
¹⁶⁷Tm	69	98	166.9328516(29)	9.25(2) d	EC	¹⁶⁷Er	1/2+
^167m1Tm	179.480(19) keV			1.16(6) µs			(7/2)+
^167m2Tm	292.820(20) keV			0.9(1) µs			7/2-
¹⁶⁸Tm	69	99	167.934173(3)	93.1(2) d	β⁺ (99.99%)	¹⁶⁸Er	3+
¹⁶⁸Tm	69	99	167.934173(3)	93.1(2) d	β^- (.01%)	¹⁶⁸Yb	3+
¹⁶⁹Tm	69	100	168.9342133(27)	Observationally Stable^{[n 3]}			1/2+	1.0000
¹⁷⁰Tm	69	101	169.9358014(27)	128.6(3) d	β^- (99.86%)	¹⁷⁰Yb	1-
¹⁷⁰Tm	69	101	169.9358014(27)	128.6(3) d	EC (.14%)	¹⁷⁰Er	1-
^170mTm	183.197(4) keV			4.12(13) µs			(3)+
¹⁷¹Tm	69	102	170.9364294(28)	1.92(1) a	β^-	¹⁷¹Yb	1/2+
^171mTm	424.9560(15) keV			2.60(2) µs			7/2-
¹⁷²Tm	69	103	171.938400(6)	63.6(2) h	β^-	¹⁷²Yb	2-
¹⁷³Tm	69	104	172.939604(5)	8.24(8) h	β^-	¹⁷³Yb	(1/2+)
^173mTm	317.73(20) keV			10(3) µs			(7/2-)
¹⁷⁴Tm	69	105	173.94217(5)	5.4(1) min	β^-	¹⁷⁴Yb	(4)-
¹⁷⁵Tm	69	106	174.94384(5)	15.2(5) min	β^-	¹⁷⁵Yb	(1/2+)
¹⁷⁶Tm	69	107	175.94699(11)	1.85(3) min	β^-	¹⁷⁶Yb	(4+)
¹⁷⁷Tm	69	108	176.94904(32)#	90(6) s	β^-	¹⁷⁷Yb	(7/2-)
¹⁷⁸Tm	69	109	177.95264(43)#	30# s	β^-	¹⁷⁸Yb
¹⁷⁹Tm	69	110	178.95534(54)#	20# s	β^-	¹⁷⁹Yb	1/2+#

^ Abbreviations:
EC: Electron capture
IT: Isomeric transition
^ Bold for stable isotopes
^ Believed to undergo α decay to ¹⁶⁵Ho

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" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
- 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. {{cite journal}}: Unknown parameter |laysummary= ignored (help)
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" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.{{cite journal}}: CS1 maint: multiple names: authors list (link)
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005. {{cite web}}: Check date values in: |accessdate= (help)
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide (ed.). CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9. {{cite book}}: Unknown parameter |nopp= ignored (|no-pp= suggested) (help)

[2] Abbreviations:
EC: Electron capture
IT: Isomeric transition

[3] Bold for stable isotopes

[4] Believed to undergo α decay to ¹⁶⁵Ho

[1] ttp://www.nucleonica.net/unc.aspx

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