Isotopes of ytterbium

Naturally occurring ytterbium (₇₀Yb) is composed of seven stable isotopes:^{[n 1] 168}Yb, ¹⁷⁰Yb–¹⁷⁴Yb, and ¹⁷⁶Yb, with ¹⁷⁴Yb being the most abundant (31.90% natural abundance). 30 radioisotopes have been characterized, with the most stable being ¹⁶⁹Yb with a half-life of 32.014 days, ¹⁷⁵Yb with a half-life of 4.185 days, and ¹⁶⁶Yb with a half-life of 56.7 hours. All of the remaining radioactive isotopes have half-lives that are less than 2 hours, with the majority of them being less than 20 minutes. This element also has 18 meta states, with the most stable being ^169mYb (half-life 46 seconds).

Isotopes of ytterbium (₇₀Yb)

Main isotopes[1] Decay abun­dance half-life (t1/2) mode pro­duct 166Yb synth 56.7 h ε 166Tm 168Yb 0.126% stable 169Yb synth 32.014 d ε 169Tm 170Yb 3.02% stable 171Yb 14.2% stable 172Yb 21.8% stable 173Yb 16.1% stable 174Yb 31.9% stable 175Yb synth 4.185 d β− 175Lu 176Yb 12.9% stable
Standard atomic weight Ar°(Yb)
	173.045±0.010[2] 173.05±0.02 (abridged)[3]
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The known isotopes of ytterbium range from ¹⁴⁹Yb to ¹⁸⁷Yb. The primary decay mode before the most abundant stable isotope, ¹⁷⁴Yb is electron capture giving thulium isotopes; the primary mode after is beta emission givivg lutetium isotopes. Of interest^[why?] to modern quantum optics, the different ytterbium isotopes follow either Bose–Einstein statistics or Fermi–Dirac statistics, leading to different behavior in optical lattices.

List of isotopes

Nuclide [n 2]	Z	N	Isotopic mass (Da)[4] [n 3][n 4]	Half-life[1] [n 5]	Decay mode[1] [n 6]	Daughter isotope [n 7]	Spin and parity[1] [n 5]	Natural abundance (mole fraction)
	Excitation energy[n 5]							Normal proportion[1]	Range of variation
149Yb	70	79	148.96422(32)#	0.7(2) s	β+, p	148Er	(1/2+)
					β+ (rare)	149Tm
150Yb	70	80	149.95831(32)#	700# ms [>200 ns]	β+?	150Tm	0+
151Yb	70	81	150.95540(32)	1.6(5) s	β+	151Tm	(1/2+)
					β+, p (rare)	150Er
151m1Yb	740(100)# keV			1.6(5) s	β+	151Tm	(11/2−)
					β+, p (rare)	150Er
151m2Yb	2630(141)# keV			2.6(7) μs	IT	151Yb	19/2−#
151m3Yb	3287(141)# keV			20(1) μs	IT	151Yb	27/2−#
152Yb	70	82	151.95033(16)	3.03(6) s	β+	152Tm	0+
152mYb	2744.5(10) keV			30(1) μs	IT	152Yb	(10+)
153Yb	70	83	152.94937(22)#	4.2(2) s	β+	153Tm	7/2−
					β+, p (0.008%)	152Er
153mYb	2630(50)# keV			15(1) μs	IT	153Yb	27/2−
154Yb	70	84	153.946396(19)	0.409(2) s	α (92.6%)	150Er	0+
					β+ (7.4%)	154Tm
155Yb	70	85	154.945783(18)	1.793(20) s	α (89%)	151Er	(7/2−)
					β+ (11%)	155Tm
156Yb	70	86	155.942817(10)	26.1(7) s	β+ (90%)	156Tm	0+
					α (10%)	152Er
157Yb	70	87	156.942651(12)	38.6(10) s	β+	157Tm	7/2−
					α (rare)	153Er
158Yb	70	88	157.939871(9)	1.49(13) min	β+ (99.99%)	158Tm	0+
					α (.0021%)	154Er
159Yb	70	89	158.940060(19)	1.67(9) min	β+	159Tm	5/2−
160Yb	70	90	159.937559(6)	4.8(2) min	β+	160Tm	0+
161Yb	70	91	160.937912(16)	4.2(2) min	β+	161Tm	3/2−
162Yb	70	92	161.935779(16)	18.87(19) min	β+	162Tm	0+
163Yb	70	93	162.936345(16)	11.05(35) min	β+	163Tm	3/2−
164Yb	70	94	163.934501(16)	75.8(17) min	EC	164Tm	0+
165Yb	70	95	164.935270(28)	9.9(3) min	β+	165Tm	5/2−
165mYb	126.80(9) keV			300(30) ns	IT	165Yb	9/2+
166Yb	70	96	165.933876(8)	56.7(1) h	EC	166Tm	0+
167Yb	70	97	166.934954(4)	17.5(2) min	β+	167Tm	5/2−
167mYb	571.548(22) keV			~180 ns	IT	167Yb	11/2−
168Yb	70	98	167.93389130(10)	Observationally Stable[n 8]			0+	0.00123(3)
169Yb	70	99	168.93518421(19)	32.014(5) d	EC	169Tm	7/2+
169mYb	24.1999(16) keV			46(2) s	IT	169Yb	1/2−
170Yb	70	100	169.934767243(11)	Observationally Stable[n 9]			0+	0.02982(39)
170mYb	1258.46(14) keV			370(15) ns	IT	170Yb	4−
171Yb	70	101	170.936331515(14)	Observationally Stable[n 10]			1/2−	0.14086(140)
171m1Yb	95.282(2) keV			5.25(24) ms	IT	171Yb	7/2+
171m2Yb	122.416(2) keV			265(20) ns	IT	171Yb	5/2−
172Yb	70	102	171.936386654(15)	Observationally Stable[n 11]			0+	0.21686(130)
172mYb	1550.43(6) keV			3.6(1) μs	IT	172Yb	6−
173Yb	70	103	172.938216212(12)	Observationally Stable[n 12]			5/2−	0.16103(63)
173mYb	398.9(5) keV			2.9(1) μs	IT	173Yb	1/2−
174Yb	70	104	173.938867546(12)	Observationally Stable[n 13]			0+	0.32025(80)
174m1Yb	1518.148(13) keV			830(40) μs	IT	174Yb	6+
174m2Yb	1765.2(5) keV			256(11) ns	IT	174Yb	7−
175Yb	70	105	174.94128191(8)	4.185(1) d	β−	175Lu	7/2−
175mYb	514.866(4) keV			68.2(3) ms	IT	175Yb	1/2−
176Yb	70	106	175.942574706(16)	Observationally Stable[n 14]			0+	0.12995(83)
176mYb	1049.8(6) keV			11.4(3) s	IT	176Yb	8−
					β− (<10#%)	176Lu
177Yb	70	107	176.94526385(24)	1.911(3) h	β−	177Lu	9/2+
177mYb	331.5(3) keV			6.41(2) s	IT	177Yb	1/2−
178Yb	70	108	177.946669(7)	74(3) min	β−	178Lu	0+
179Yb	70	109	178.94993(22)#	8.0(4) min	β−	179Lu	(1/2−)
180Yb	70	110	179.95199(32)#	2.4(5) min	β−	180Lu	0+
181Yb	70	111	180.95589(32)#	1# min [>300 ns]	β−?	181Lu	3/2−#
182Yb	70	112	181.95824(43)#	30# s [>300 ns]	β−?	182Lu	0+
183Yb	70	113	182.96243(43)#	30# s [>300 ns]	β−?	183Lu	3/2−#
184Yb	70	114	183.96500(54)#	7# s [>300 ns]	β−?	184Lu	0+
185Yb	70	115	184.96943(54)#	5# s [>300 ns]	β−?	185Lu	9/2−#
186Yb[5]	70	116					0+
187Yb[5]	70	117
This table header & footer: view

1. However, all seven of the isotopes are observationally stable, meaning that they are predicted to be radioactive but decay has not been observed yet.
2. ^mYb – Excited nuclear isomer.
3. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
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. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
6. Modes of decay:

   EC:	Electron capture
   IT:	Isomeric transition

7. Bold symbol as daughter – Daughter product is stable.
8. Believed to undergo α decay to ¹⁶⁴Er or β⁺β⁺ decay to ¹⁶⁸Er with a half-life over 130×10¹² years
9. Believed to undergo α decay to ¹⁶⁶Er
10. Believed to undergo α decay to ¹⁶⁷Er
11. Believed to undergo α decay to ¹⁶⁸Er
12. Believed to undergo α decay to ¹⁶⁹Er
13. Believed to undergo α decay to ¹⁷⁰Er
14. Believed to undergo α decay to ¹⁷²Er or β⁻β⁻ decay to ¹⁷⁶Hf with a half-life over 160×10¹⁵ years

See also

Daughter products other than ytterbium

• Isotopes of lutetium
• Isotopes of thulium
• Isotopes of erbium