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Isotopes of erbium



Naturally occurring Erbium (Er) is composed of 6 stable isotopes, Er-162, Er-164, Er-166, Er-167, Er-168, and Er-170 with Er-166 being the most abundant (33.503% natural abundance). 29 radioisotopes have been characterized, with the most stable being Er-169 with a half life of 9.4 days, Er-172 with a half-life of 49.3 hours, Er-160 with a half-life of 28.58 hours, Er-165 with a half-life of 10.36 hours, and Er-171 with a half life of 7.516 hours. All of the remaining radioactive isotopes have half-lifes that are less than 3.5 hours, and the majority of these have half lifes that are less than 4 minutes. This element also has 13 meta states, with the most stable being Er-167m (t½ 2.269 seconds).

Additional recommended knowledge

The isotopes of erbium range in atomic weight from 142.9663 u (Er-143) to 176.9541 u (Er-177). The primary decay mode before the most abundant stable isotope, Er-166, is electron capture, and the primary mode after is beta decay. The primary decay products before Er-166 are element 67 (holmium) isotopes, and the primary products after are element 69 (thulium) isotopes.
Standard atomic mass: 167.259(3) u

Table

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life nuclear
spin
representative
isotopic
composition
(mole fraction)
range of natural
variation
(mole fraction)
excitation energy
143Er 68 75 142.96634(64)# 200# ms 9/2-#
144Er 68 76 143.96038(43)# 400# ms [>200 ns] 0+
145Er 68 77 144.95739(43)# 900(300) ms 1/2+#
146Er 68 78 145.95200(32)# 1.7(6) s 0+
147Er 68 79 146.94949(32)# ~2.5 s (1/2+)
147mEr 100(50)# keV 2.5(2) s (11/2-)
148Er 68 80 147.94455(21)# 4.6(2) s 0+
149Er 68 81 148.94231(3) 4(2) s (1/2+)
149m1Er 741.8(2) keV 8.9(2) s (11/2-)
149m2Er 2611.1(3) keV 0.61(8) µs (19/2+)
149m3Er 3242.7+X keV 4.8(1) µs (27/2-)
150Er 68 82 149.937914(18) 18.5(7) s 0+
151Er 68 83 150.937449(18) 23.5(13) s (7/2-)
151m1Er 2585.5(6) keV 580(20) ms (27/2-)
151m2Er 10286+X keV 0.42(5) µs (67/2,69/2,71/2)
152Er 68 84 151.935050(11) 10.3(1) s 0+
153Er 68 85 152.935063(9) 37.1(2) s 7/2(-)
154Er 68 86 153.932783(6) 3.73(9) min 0+
155Er 68 87 154.933209(7) 5.3(3) min 7/2-
156Er 68 88 155.931065(26) 19.5(10) min 0+
157Er 68 89 156.93192(3) 18.65(10) min 3/2-
157mEr 155.4(3) keV 76(6) ms (9/2+)
158Er 68 90 157.929893(27) 2.29(6) h 0+
159Er 68 91 158.930684(5) 36(1) min 3/2-
159m1Er 182.602(24) keV 337(14) ns 9/2+
159m2Er 429.05(3) keV 590(60) ns 11/2-
160Er 68 92 159.929083(26) 28.58(9) h 0+
161Er 68 93 160.929995(10) 3.21(3) h 3/2-
161mEr 396.44(4) keV 7.5(7) µs 11/2-
162Er 68 94 161.928778(4) STABLE [>140E+12 a] 0+ 0.00139(5)
163Er 68 95 162.930033(6) 75.0(4) min 5/2-
163mEr 445.5(6) keV 580(100) ns (11/2-)
164Er 68 96 163.929200(3) STABLE 0+ 0.01601(3)
165Er 68 97 164.930726(3) 10.36(4) h 5/2-
166Er 68 98 165.9302931(27) STABLE 0+ 0.33503(36)
167Er 68 99 166.9320482(27) STABLE 7/2+ 0.22869(9)
167mEr 207.801(5) keV 2.269(6) s 1/2-
168Er 68 100 167.9323702(27) STABLE 0+ 0.26978(18)
169Er 68 101 168.9345904(27) 9.392(18) d 1/2-
170Er 68 102 169.9354643(30) STABLE [>320E+15 a] 0+ 0.14910(36)
171Er 68 103 170.9380298(30) 7.516(2) h 5/2-
171mEr 198.6(1) keV 210(10) ns 1/2-
172Er 68 104 171.939356(5) 49.3(3) h 0+
173Er 68 105 172.94240(21)# 1.434(17) min (7/2-)
174Er 68 106 173.94423(32)# 3.2(2) min 0+
175Er 68 107 174.94777(43)# 1.2(3) min (9/2+)
176Er 68 108 175.95008(43)# 20# s 0+
177Er 68 109 176.95405(54)# 3# s 1/2-#

Notes

References

  • Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
  • Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
  • Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
    • Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
    • National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
    • David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.


Isotopes of holmium Isotopes of erbium Isotopes of thulium
Index to isotope pages
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isotopes_of_erbium". A list of authors is available in Wikipedia.
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