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 (31.83% natural abundance). 30 radioisotopes have been characterized, with the most stable being ¹⁶⁹Yb with a half-life of 32.026 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, and the majority of these have half-lives that are less than 20 minutes. This element also has 18 meta states, with the most stable being ^169mYb (t_1/2 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 32.026 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 isotopes of ytterbium range from ¹⁴⁹Yb to ¹⁸⁷Yb. The primary decay mode before the most abundant stable isotope, ¹⁷⁴Yb is electron capture, and the primary mode after is beta emission. The primary decay products before ¹⁷⁴Yb are isotopes of thulium, and the primary products after are isotopes of lutetium. Of interest to modern quantum optics, the different ytterbium isotopes follow either Bose–Einstein statistics or Fermi–Dirac statistics, leading to interesting 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