Isotopes of erbium

Isotopes of erbium (₆₈Er)
Standard atomic weight Ar°(Er)
	167.259±0.003; 167.26±0.01 (abridged);
	view ; talk ; edit ;

Last updated November 06, 2024

Naturally occurring erbium (₆₈Er) is composed of six stable isotopes, with ¹⁶⁶Er being the most abundant (33.503% natural abundance). Thirty-nine radioisotopes have been characterized with between 74 and 112 neutrons, or 142 to 180 nucleons, with the most stable being ¹⁶⁹Er with a half-life of 9.4 days, ¹⁷²Er with a half-life of 49.3 hours, ¹⁶⁰Er with a half-life of 28.58 hours, ¹⁶⁵Er with a half-life of 10.36 hours, and ¹⁷¹Er with a half-life of 7.516 hours. All of the remaining radioactive isotopes have half-lives that are less than 3.5 hours, and the majority of these have half-lives that are less than 4 minutes. This element also has numerous meta states, with the most stable being ^167mEr (t_1/2 = 2.269 seconds).

The isotopes of erbium range in atomic weight from 141.9723 u (¹⁴²Er) to 179.9644 u (¹⁸⁰Er). The primary decay mode before the most abundant stable isotope, ¹⁶⁶Er, is electron capture, and the primary mode after is beta decay. The primary decay products before ¹⁶⁶Er are holmium isotopes, and the primary products after are thulium isotopes. All isotopes of erbium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da)^[4] ^{[n 2]}^{[n 3]}	Half-life ^[1] ^{[n 4]}	Decay mode ^[1] ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^[1] ^{[n 7]}^{[n 4]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy^{[n 4]}			Half-life ^[1] ^{[n 4]}	Decay mode ^[1] ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^[1] ^{[n 7]}^{[n 4]}	Normal proportion^[1]	Range of variation
¹⁴³Er	68	75	142.96655(43)#	200# ms			9/2−#
¹⁴⁴Er	68	76	143.96070(21)#	400# ms [>200 ns]			0+
¹⁴⁵Er	68	77	144.95787(22)#	900(200) ms	β⁺	¹⁴⁵Ho	1/2+#
¹⁴⁵Er	68	77	144.95787(22)#	900(200) ms	β⁺, p (?%)	¹⁴⁴Dy	1/2+#
^145mEr	205(4)# keV			1.0(3) s	β⁺	¹⁴⁵Ho	(11/2-)
^145mEr	205(4)# keV			1.0(3) s	β⁺, p (?%)	¹⁴⁴Dy	(11/2-)
¹⁴⁶Er	68	78	145.952418(7)	1.7(6) s	β⁺	¹⁴⁶Ho	0+
¹⁴⁶Er	68	78	145.952418(7)	1.7(6) s	β⁺, p (?%)	¹⁴⁵Dy	0+
¹⁴⁷Er	68	79	146.94996(4)#	3.2(12) s	β⁺	¹⁴⁷Ho	(1/2+)
¹⁴⁷Er	68	79	146.94996(4)#	3.2(12) s	β⁺, p (?%)	¹⁴⁶Dy	(1/2+)
^147mEr^{[n 8]}	100(50)# keV			1.6(2) s	β⁺	¹⁴⁷Ho	(11/2−)
^147mEr^{[n 8]}	100(50)# keV			1.6(2) s	β⁺, p (?%)	¹⁴⁶Dy	(11/2−)
¹⁴⁸Er	68	80	147.944735(11)#	4.6(2) s	β⁺ (99.85%)	¹⁴⁸Ho	0+
¹⁴⁸Er	68	80	147.944735(11)#	4.6(2) s	β⁺, p (0.15%)	¹⁴⁷Dy	0+
^148mEr	2.9132(4) MeV			13(3) μs	IT	¹⁴⁸Er	(10+)
¹⁴⁹Er	68	81	148.94231(3)	4(2) s	β⁺ (93%)	¹⁴⁹Ho	(1/2+)
¹⁴⁹Er	68	81	148.94231(3)	4(2) s	β⁺, p (7%)	¹⁴⁸Dy	(1/2+)
^149m1Er	741.8(2) keV			8.9(2) s	β⁺ (96.3%)	¹⁴⁹Ho	(11/2−)
					IT (3.5%)	¹⁴⁹Er
					β⁺, p (0.18%)	¹⁴⁸Dy
^149m2Er	2.6111(3) MeV			0.61(8) μs	IT	¹⁴⁹Er	(19/2+)
^149m3Er	3.302(7) MeV			4.8(1) μs	IT	¹⁴⁹Er	(27/2−)
¹⁵⁰Er	68	82	149.937916(18)	18.5(7) s	β⁺	¹⁵⁰Ho	0+
^150mEr	2.7965(5) MeV			2.55(10) μs	IT	¹⁵⁰Er	10+
¹⁵¹Er	68	83	150.937449(18)	23.5(20) s	β⁺	¹⁵¹Ho	(7/2−)
^151m1Er	2.5860(5) MeV			580(20) ms	IT (95.3%)	¹⁵¹Er	(27/2−)
^151m1Er	2.5860(5) MeV			580(20) ms	β⁺ (4.7%)	¹⁵¹Ho	(27/2−)
^151m2Er	10.2866(10) MeV			0.42(5) μs	IT	¹⁵¹Er	(65/2-, 61/2+)
¹⁵²Er	68	84	151.935050(9)	10.3(1) s	α (90%)	¹⁴⁸Dy	0+
¹⁵²Er	68	84	151.935050(9)	10.3(1) s	β⁺ (10%)	¹⁵²Ho	0+
¹⁵³Er	68	85	152.935086(10)	37.1(2) s	α (53%)	¹⁴⁹Dy	7/2−
¹⁵³Er	68	85	152.935086(10)	37.1(2) s	β⁺ (47%)	¹⁵³Ho	7/2−
^153m1Er	2.7982(10) MeV			373(9) ns	IT	¹⁵³Er	(27/2-)
^153m2Er	5.2481(10) MeV			248(32) ns	IT	¹⁵³Er	(41/2-)
¹⁵⁴Er	68	86	153.932791(5)	3.73(9) min	β⁺ (99.53%)	¹⁵⁴Ho	0+
¹⁵⁴Er	68	86	153.932791(5)	3.73(9) min	α (0.47%)	¹⁵⁰Dy	0+
¹⁵⁵Er	68	87	154.933216(7)	5.3(3) min	β⁺ (99.978%)	¹⁵⁵Ho	7/2−
¹⁵⁵Er	68	87	154.933216(7)	5.3(3) min	α (0.022%)	¹⁵¹Dy	7/2−
¹⁵⁶Er	68	88	155.931066(26)	19.5(10) min	β⁺	¹⁵⁶Ho	0+
¹⁵⁶Er	68	88	155.931066(26)	19.5(10) min	α (1.2×10⁻⁵%)	¹⁵²Dy	0+
¹⁵⁷Er	68	89	156.931923(28)	18.65(10) min	β⁺	¹⁵⁷Ho	3/2−
^157mEr	155.4(3) keV			76(6) ms	IT	¹⁵⁷Er	9/2+
¹⁵⁸Er	68	90	157.929893(27)	2.29(6) h	EC	¹⁵⁸Ho	0+
¹⁵⁹Er	68	91	158.930691(4)	36(1) min	β⁺	¹⁵⁹Ho	3/2−
^159m1Er	182.602(24) keV			337(14) ns	IT	¹⁵⁹Er	9/2+
^159m2Er	429.05(3) keV			590(60) ns	IT	¹⁵⁹Er	11/2−
¹⁶⁰Er	68	92	159.929077(26)	28.58(9) h	EC	¹⁶⁰Ho	0+
¹⁶¹Er	68	93	160.930004(9)	3.21(3) h	β⁺	¹⁶¹Ho	3/2−
^161mEr	396.44(4) keV			7.5(7) μs	IT	¹⁶¹Er	11/2−
¹⁶²Er	68	94	161.9287873(8)	Observationally Stable ^{[n 9]}			0+	0.00139(5)
^162mEr	2.02601(13) MeV			88(16) ns	IT	¹⁶²Er	7(-)
¹⁶³Er	68	95	162.930040(5)	75.0(4) min	β⁺	¹⁶³Ho	5/2−
^163mEr	445.5(6) keV			580(100) ns	IT	¹⁶³Er	(11/2−)
¹⁶⁴Er	68	96	163.9292077(8)	Observationally Stable^{[n 10]}			0+	0.01601(3)
¹⁶⁵Er	68	97	164.9307335(10)	10.36(4) h	EC	¹⁶⁵Ho	5/2−
^165m1Er	551.3(6) keV			250(30) ns	IT	¹⁶⁵Er	11/2-
^165m2Er	1.8230(6) MeV			370(40) ns	IT	¹⁶⁵Er	(19/2)
¹⁶⁶Er	68	98	165.9303011(4)	Observationally Stable^{[n 11]}			0+	0.33503(36)
¹⁶⁷Er	68	99	166.9320562(3)	Observationally Stable^{[n 12]}			7/2+	0.22869(9)
^167mEr	207.801(5) keV			2.269(6) s	IT	¹⁶⁷Er	1/2−
¹⁶⁸Er	68	100	167.93237828(28)	Observationally Stable^{[n 13]}			0+	0.26978(18)
^168mEr	1.0940383(16) MeV			109.0(7) ns	IT	¹⁶⁸Er	4-
¹⁶⁹Er	68	101	168.9345984(3)	9.392(18) d	β⁻	¹⁶⁹Tm	1/2−
^169m1Er	92.05(10) keV			285(20) ns	IT	¹⁶⁹Er	(5/2)-
^169m2Er	243.69(17) keV			200(10) ns	IT	¹⁶⁹Er	7/2+
¹⁷⁰Er	68	102	169.9354719(15)	Observationally Stable^{[n 14]}			0+	0.14910(36)
¹⁷¹Er	68	103	170.93803746(15)	7.516(2) h	β⁻	¹⁷¹Tm	5/2−
^171mEr	198.61(9) keV			210(10) ns	IT	¹⁷¹Er	1/2−
¹⁷²Er	68	104	171.939363(4)	49.3(5) h	β⁻	¹⁷²Tm	0+
^172mEr	1.5009(3) MeV			579(62) ns	IT	¹⁷²Er	(6+)
¹⁷³Er	68	105	172.94240(21)#	1.434(17) min	β⁻	¹⁷³Tm	(7/2−)
¹⁷⁴Er	68	106	173.94423(32)#	3.2(2) min	β⁻	¹⁷⁴Tm	0+
^174mEr	1.1115(7) MeV			3.9(3) s	IT	¹⁷⁴Er	8-
¹⁷⁵Er	68	107	174.94777(43)#	1.2(3) min	β⁻	¹⁷⁵Tm	9/2+#
¹⁷⁶Er	68	108	175.94994(43)#	12# s [>300 ns]			0+
¹⁷⁷Er	68	109	176.95399(54)#	8# s [>300 ns]			1/2−#
¹⁷⁸Er	68	110	177.95678(64)#	4# s [>300 ns]			0+
¹⁷⁹Er	68	111	178.96127(54)#	3# s [>550 ns)]			3/2−#
¹⁸⁰Er	68	112	179.96438(54)#	2# s [>550 ns]			0+
This table header & footer: view

↑ ^mEr – 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).
1 2 3 # – 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
p: Proton emission
↑ Bold symbol as daughter – Daughter product is stable.
↑ ( ) spin value – Indicates spin with weak assignment arguments.
↑ Order of ground state and isomer is uncertain.
↑ Believed to undergo α decay to ¹⁵⁸Dy or β⁺β⁺ to ¹⁶²Dy with a half-life over 1.40×10¹⁴ years
↑ Believed to undergo α decay to ¹⁶⁰Dy or β⁺β⁺ to ¹⁶⁴Dy
↑ Believed to undergo α decay to ¹⁶²Dy
↑ Believed to undergo α decay to ¹⁶³Dy
↑ Believed to undergo α decay to ¹⁶⁴Dy
↑ Believed to undergo α decay to ¹⁶⁶Dy or β⁻β⁻ to ¹⁷⁰Yb with a half-life over 4.10×10¹⁷ years

Related Research Articles

Fluorine (₉F) has 19 known isotopes ranging from ¹³
F to ³¹
F and two isomers. Only fluorine-19 is stable and naturally occurring in more than trace quantities; therefore, fluorine is a monoisotopic and mononuclidic element.

Francium (₈₇Fr) has no stable isotopes. A standard atomic weight cannot be given. Its most stable isotope is ²²³Fr with a half-life of 22 minutes, occurring in trace quantities in nature as an intermediate decay product of ²³⁵U.

There are 39 known isotopes of radon (₈₆Rn), from ¹⁹³Rn to ²³¹Rn; all are radioactive. The most stable isotope is ²²²Rn with a half-life of 3.823 days, which decays into ²¹⁸
Po. Six isotopes of radon, ^{217, 218, 219, 220, 221, 222}Rn, occur in trace quantities in nature as decay products of, respectively, ²¹⁷At, ²¹⁸At, ²²³Ra, ²²⁴Ra, ²²⁵Ra, and ²²⁶Ra. ²¹⁷Rn and ²²¹Rn are produced in rare branches in the decay chain of trace quantities of ²³⁷Np; ²²²Rn is an intermediate step in the decay chain of ²³⁸U; ²¹⁹Rn is an intermediate step in the decay chain of ²³⁵U; and ²²⁰Rn occurs in the decay chain of ²³²Th.

Astatine (₈₅At) has 41 known isotopes, all of which are radioactive; their mass numbers range from 188 to 229. There are also 24 known metastable excited states. The longest-lived isotope is ²¹⁰At, which has a half-life of 8.1 hours; the longest-lived isotope existing in naturally occurring decay chains is ²¹⁹At with a half-life of 56 seconds.

There are 42 isotopes of polonium (₈₄Po). They range in size from 186 to 227 nucleons. They are all radioactive. ²¹⁰Po with a half-life of 138.376 days has the longest half-life of any naturally-occurring isotope of polonium and is the most common isotope of polonium. It is also the most easily synthesized polonium isotope. ²⁰⁹Po, which does not occur naturally, has the longest half-life of all isotopes of polonium at 124 years. ²⁰⁹Po can be made by using a cyclotron to bombard bismuth with protons, as can ²⁰⁸Po.

Thallium (₈₁Tl) has 41 isotopes with atomic masses that range from 176 to 216. ²⁰³Tl and ²⁰⁵Tl are the only stable isotopes and ²⁰⁴Tl is the most stable radioisotope with a half-life of 3.78 years. ²⁰⁷Tl, with a half-life of 4.77 minutes, has the longest half-life of naturally occurring Tl radioisotopes. All isotopes of thallium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.

There are seven stable isotopes of mercury (₈₀Hg) with ²⁰²Hg being the most abundant (29.86%). The longest-lived radioisotopes are ¹⁹⁴Hg with a half-life of 444 years, and ²⁰³Hg with a half-life of 46.612 days. Most of the remaining 40 radioisotopes have half-lives that are less than a day. ¹⁹⁹Hg and ²⁰¹Hg are the most often studied NMR-active nuclei, having spin quantum numbers of 1/2 and 3/2 respectively. All isotopes of mercury are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. These isotopes are predicted to undergo either alpha decay or double beta decay.

Gold (₇₉Au) has one stable isotope, ¹⁹⁷Au, and 40 radioisotopes, with ¹⁹⁵Au being the most stable with a half-life of 186 days. Gold is currently considered the heaviest monoisotopic element. Bismuth formerly held that distinction until alpha-decay of the ²⁰⁹Bi isotope was observed. All isotopes of gold are either radioactive or, in the case of ¹⁹⁷Au, observationally stable, meaning that ¹⁹⁷Au is predicted to be radioactive but no actual decay has been observed.

Naturally occurring platinum (₇₈Pt) consists of five stable isotopes (¹⁹²Pt, ¹⁹⁴Pt, ¹⁹⁵Pt, ¹⁹⁶Pt, ¹⁹⁸Pt) and one very long-lived (half-life 4.83×10¹¹ years) radioisotope (¹⁹⁰Pt). There are also 34 known synthetic radioisotopes, the longest-lived of which is ¹⁹³Pt with a half-life of 50 years. All other isotopes have half-lives under a year, most under a day. All isotopes of platinum are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. Platinum-195 is the most abundant isotope.

There are two natural isotopes of iridium (₇₇Ir), and 37 radioisotopes, the most stable radioisotope being ¹⁹²Ir with a half-life of 73.83 days, and many nuclear isomers, the most stable of which is ^192m2Ir with a half-life of 241 years. All other isomers have half-lives under a year, most under a day. All isotopes of iridium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.

Naturally occurring ytterbium (₇₀Yb) is composed of seven stable isotopes: ¹⁶⁸Yb, ¹⁷⁰Yb–¹⁷⁴Yb, and ¹⁷⁶Yb, with ¹⁷⁴Yb being the most abundant. 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, 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.

Naturally occurring thulium (₆₉Tm) is composed of one stable isotope, ¹⁶⁹Tm. Thirty-nine 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, ^160mTm and ^155mTm.

Naturally occurring dysprosium (₆₆Dy) is composed of 7 stable isotopes, ¹⁵⁶Dy, ¹⁵⁸Dy, ¹⁶⁰Dy, ¹⁶¹Dy, ¹⁶²Dy, ¹⁶³Dy and ¹⁶⁴Dy, with ¹⁶⁴Dy being the most abundant. Twenty-nine radioisotopes have been characterized, with the most stable being ¹⁵⁴Dy with a half-life of 1.4 million years, ¹⁵⁹Dy with a half-life of 144.4 days, and ¹⁶⁶Dy with a half-life of 81.6 hours. All of the remaining radioactive isotopes have half-lives that are less than 10 hours, and the majority of these have half-lives that are less than 30 seconds. This element also has 12 meta states, with the most stable being ^165mDy, ^147mDy and ^145mDy.

Naturally occurring gadolinium (₆₄Gd) is composed of 6 stable isotopes, ¹⁵⁴Gd, ¹⁵⁵Gd, ¹⁵⁶Gd, ¹⁵⁷Gd, ¹⁵⁸Gd and ¹⁶⁰Gd, and 1 radioisotope, ¹⁵²Gd, with ¹⁵⁸Gd being the most abundant (24.84% natural abundance). The predicted double beta decay of ¹⁶⁰Gd has never been observed; only a lower limit on its half-life of more than 1.3×10²¹ years has been set experimentally.

Naturally occurring praseodymium (₅₉Pr) is composed of one stable isotope, ¹⁴¹Pr. Thirty-eight radioisotopes have been characterized with the most stable being ¹⁴³Pr, with a half-life of 13.57 days and ¹⁴²Pr, with a half-life of 19.12 hours. All of the remaining radioactive isotopes have half-lives that are less than 5.985 hours and the majority of these have half-lives that are less than 33 seconds. This element also has 15 meta states with the most stable being ^138mPr, ^142mPr and ^134mPr.

Naturally occurring cerium (₅₈Ce) is composed of 4 stable isotopes: ¹³⁶Ce, ¹³⁸Ce, ¹⁴⁰Ce, and ¹⁴²Ce, with ¹⁴⁰Ce being the most abundant and the only one theoretically stable; ¹³⁶Ce, ¹³⁸Ce, and ¹⁴²Ce are predicted to undergo double beta decay but this process has never been observed. There are 35 radioisotopes that have been characterized, with the most stable being ¹⁴⁴Ce, with a half-life of 284.893 days; ¹³⁹Ce, with a half-life of 137.640 days and ¹⁴¹Ce, with a half-life of 32.501 days. All of the remaining radioactive isotopes have half-lives that are less than 4 days and the majority of these have half-lives that are less than 10 minutes. This element also has 10 meta states.

Naturally occurring silver (₄₇Ag) is composed of the two stable isotopes ¹⁰⁷Ag and ¹⁰⁹Ag in almost equal proportions, with ¹⁰⁷Ag being slightly more abundant. Notably, silver is the only element with all stable istopes having nuclear spins of 1/2. Thus both ¹⁰⁷Ag and ¹⁰⁹Ag nuclei produce narrow lines in nuclear magnetic resonance spectra.

Bromine (₃₅Br) has two stable isotopes, ⁷⁹Br and ⁸¹Br, and 35 known radioisotopes, the most stable of which is ⁷⁷Br, with a half-life of 57.036 hours.

Naturally occurring scandium (₂₁Sc) is composed of one stable isotope, ⁴⁵Sc. Twenty-seven radioisotopes have been characterized, with the most stable being ⁴⁶Sc with a half-life of 83.8 days, ⁴⁷Sc with a half-life of 3.35 days, and ⁴⁸Sc with a half-life of 43.7 hours and ⁴⁴Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound ³⁹Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being ^44m2Sc.

Fermium (₁₀₀Fm) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be discovered was ²⁵⁵Fm in 1952. ²⁵⁰Fm was independently synthesized shortly after the discovery of ²⁵⁵Fm. There are 20 known radioisotopes ranging in atomic mass from ²⁴¹Fm to ²⁶⁰Fm, and 4 nuclear isomers, ^247mFm, ^250mFm, ^251mFm, and ^253mFm. The longest-lived isotope is ²⁵⁷Fm with a half-life of 100.5 days, and the longest-lived isomer is ^247mFm with a half-life of 5.1 seconds.

References

1 2 3 4 5 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: Erbium". CIAAW. 1999.
↑ 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.
↑ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.

Isotope masses from:
- Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
Isotopic compositions and standard atomic masses from:
- 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.
- 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.
- 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.
- 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.

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[4] Er – Excited nuclear isomer.

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

[TMS-7] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[TNN-8] 1 2 3 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[9] Modes of decay:
EC: Electron capture
IT: Isomeric transition
p: Proton emission

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

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

[order-12] Order of ground state and isomer is uncertain.

[13] Believed to undergo α decay to ¹⁵⁸Dy or β⁺β⁺ to ¹⁶²Dy with a half-life over 1.40×10¹⁴ years

[14] Believed to undergo α decay to ¹⁶⁰Dy or β⁺β⁺ to ¹⁶⁴Dy

[15] Believed to undergo α decay to ¹⁶²Dy

[16] Believed to undergo α decay to ¹⁶³Dy

[17] Believed to undergo α decay to ¹⁶⁴Dy

[18] Believed to undergo α decay to ¹⁶⁶Dy or β⁻β⁻ to ¹⁷⁰Yb with a half-life over 4.10×10¹⁷ years

[NUBASE2020-1] 1 2 3 4 5 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: Erbium". CIAAW. 1999.

[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.

[AME2020_II-5] Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.

[1]

[2]

[3]

[n 1]

[4]

[n 2]

[n 3]

[n 4]

[n 5]

[n 6]

[n 7]

[n 8]

[n 9]

[n 10]

[n 11]

[n 12]

[n 13]

[n 14]