# Isotopen van erbium

Het chemisch element erbium (Er), met een atoommassa van 167,259(3) u, bezit 6 stabiele isotopen: $^{162}$Er, $^{164}$Er, $^{166}$Er, $^{167}$Er, $^{168}$Er en $^{170}$Er, waarvan $^{166}$Er het meest abundant is (ongeveer 33,5%). De 28 radio-isotopen zijn onstabiel en hebben een relatief korte halfwaardetijd (de meeste minder dan een seconde). Alle stabiele isotopen worden ervan verdacht via α-verval te vervallen tot isotopen van dysprosium, maar dit verval is nog nooit waargenomen. Bovendien is de halfwaardetijd van dit verval steeds miljoenen tot miljarden malen groter dan de leeftijd van het universum, waardoor de isotopen als stabiel mogen beschouwd worden.
De kortstlevende isotoop van erbium is $^{143}$Er, met een halfwaardetijd van ongeveer 200 milliseconden. De langstlevende is $^{169}$Er, met een halfwaardetijd van 9,4 dagen.

## Overzicht

| Nuclide | Z (p) | N (n) | Isotopische massa (u) | Halveringstijd | Radioactief verval | VP | Kernspin | Isotopische verhouding (molfractie) |
| Natuurlijk voorkomen (molfractie) |||
| $^{143}$Er | 68 | 75 | 142,96634(64) | 200 ms | | | 9/2$^−$ | |
| $^{144}$Er | 68 | 76 | 143,96038(43) | 400 ms [> 200 ns] | β$^+$ | $^{144}$Ho | 0$^+$ | |
| $^{145}$Er | 68 | 77 | 144,95739(43) | 900(300) ms | β$^+$ | $^{145}$Ho | 1/2$^+$ | |
| $^{145}$Er | 68 | 77 | 144,95739(43) | 900(300) ms | β$^+$, p (zelden) | $^{144}$Dy | 1/2$^+$ | |
| $^{146}$Er | 68 | 78 | 145,95200(32) | 1,7(6) s | β$^+$ | $^{146}$Ho | 0$^+$ | |
| $^{146}$Er | 68 | 78 | 145,95200(32) | 1,7(6) s | β$^+$, p | $^{145}$Dy | 0$^+$ | |
| $^{147}$Er | 68 | 79 | 146,94949(32) | ± 2,5 s | β$^+$ | $^{147}$Ho | (1/2$^+$) | |
| $^{147}$Er | 68 | 79 | 146,94949(32) | ± 2,5 s | β$^+$, p | $^{146}$Dy | (1/2$^+$) | |
| $^{147m}$Er | 100(50) keV | 100(50) keV | 100(50) keV | 2,5(2) s | β$^+$ | $^{147}$Ho | (11/2$^−$) | |
| $^{148}$Er | 68 | 80 | 147,94455(21) | 4,6(2) s | β$^+$ (99,85%) | $^{148}$Ho | 0$^+$ | |
| $^{148}$Er | 68 | 80 | 147,94455(21) | 4,6(2) s | β$^+$, p (0,15%) | $^{147}$Dy | 0$^+$ | |
| $^{149}$Er | 68 | 81 | 148,94231(3) | 4(2) s | β$^+$ (93%) | $^{149}$Ho | (1/2$^+$) | |
| $^{149}$Er | 68 | 81 | 148,94231(3) | 4(2) s | β$^+$, p (7%) | $^{148}$Dy | (1/2$^+$) | |
| $^{149m1}$Er | 741,8(2) keV | 741,8(2) keV | 741,8(2) keV | 8,9(2) s | β$^+$ (96,5%) | $^{149}$Ho | (11/2$^−$) | |
| $^{149m1}$Er | 741,8(2) keV | 741,8(2) keV | 741,8(2) keV | 8,9(2) s | IT (3,5%) | $^{149}$Er | (11/2$^−$) | |
| $^{149m1}$Er | 741,8(2) keV | 741,8(2) keV | 741,8(2) keV | 8,9(2) s | β$^+$, p (0,18%) | $^{148}$Dy | (11/2$^−$) | |
| $^{149m2}$Er | 2611,1(3) keV | 2611,1(3) keV | 2611,1(3) keV | 0,61(8) µs | | | (19/2$^+$) | |
| $^{149m3}$Er | 3242,7$^+$X keV | 3242,7$^+$X keV | 3242,7$^+$X keV | 4,8(1) µs | | | (27/2$^−$) | |
| $^{150}$Er | 68 | 82 | 149,937914(18) | 18,5(7) s | β$^+$ | $^{150}$Ho | 0$^+$ | |
| $^{151}$Er | 68 | 83 | 150,937449(18) | 23,5(13) s | β$^+$ | $^{151}$Ho | (7/2$^−$) | |
| $^{151m1}$Er | 2585,5(6) keV | 2585,5(6) keV | 2585,5(6) keV | 580(20) ms | IT (95,3%) | $^{151}$Er | (27/2$^−$) | |
| $^{151m1}$Er | 2585,5(6) keV | 2585,5(6) keV | 2585,5(6) keV | 580(20) ms | β$^+$ (4,7%) | $^{151}$Ho | (27/2$^−$) | |
| $^{151m2}$Er | 10286$^+$X keV | 10286$^+$X keV | 10286$^+$X keV | 0,42(5) µs | | | (67/2, 69/2, 71/2) | |
| $^{152}$Er | 68 | 84 | 151,935050(11) | 10,3(1) s | α (90%) | $^{148}$Dy | 0$^+$ | |
| $^{152}$Er | 68 | 84 | 151,935050(11) | 10,3(1) s | β$^+$ (10%) | $^{152}$Ho | 0$^+$ | |
| $^{153}$Er | 68 | 85 | 152,935063(9) | 37,1(2) s | α (53%) | $^{149}$Dy | 7/2$^−$ | |
| $^{153}$Er | 68 | 85 | 152,935063(9) | 37,1(2) s | β$^+$ (47%) | $^{153}$Ho | 7/2$^−$ | |
| $^{154}$Er | 68 | 86 | 153,932783(6) | 3,73(9) min | β$^+$ (99,53%) | $^{154}$Ho | 0$^+$ | |
| $^{154}$Er | 68 | 86 | 153,932783(6) | 3,73(9) min | α (0,47%) | $^{150}$Dy | 0$^+$ | |
| $^{155}$Er | 68 | 87 | 154,933209(7) | 5,3(3) min | β$^+$ (99,98%) | $^{155}$Ho | 7/2$^−$ | |
| $^{155}$Er | 68 | 87 | 154,933209(7) | 5,3(3) min | α (0,022%) | $^{151}$Dy | 7/2$^−$ | |
| $^{156}$Er | 68 | 88 | 155,931065(26) | 19,5(10) min | β$^+$ | $^{156}$Ho | 0$^+$ | |
| $^{157}$Er | 68 | 89 | 156,93192(3) | 18,65(10) min | β$^+$ | $^{157}$Ho | 3/2$^−$ | |
| $^{157m}$Er | 155,4(3) keV | 155,4(3) keV | 155,4(3) keV | 76(6) ms | IT | $^{157}$Er | (9/2$^+$) | |
| $^{158}$Er | 68 | 90 | 157,929893(27) | 2,29(6) uur | EV | $^{158}$Ho | 0$^+$ | |
| $^{159}$Er | 68 | 91 | 158,930684(5) | 36(1) min | β$^+$ | $^{159}$Ho | 3/2$^−$ | |
| $^{159m1}$Er | 182,602(24) keV | 182,602(24) keV | 182,602(24) keV | 337(14) ns | | | 9/2$^+$ | |
| $^{159m2}$Er | 429,05(3) keV | 429,05(3) keV | 429,05(3) keV | 590(60) ns | | | 11/2$^−$ | |
| $^{160}$Er | 68 | 92 | 159,929083(26) | 28,58(9) uur | EV | $^{160}$Ho | 0$^+$ | |
| $^{161}$Er | 68 | 93 | 160,929995(10) | 3,21(3) uur | β$^+$ | $^{161}$Ho | 3/2$^−$ | |
| $^{161m}$Er | 396,44(4) keV | 396,44(4) keV | 396,44(4) keV | 7,5(7) µs | | | 11/2$^−$ | |
| $^{162}$Er | 68 | 94 | 161,928778(4) | stabiel | stabiel | stabiel | 0$^+$ | 0,00139(5) |
| $^{163}$Er | 68 | 95 | 162,930033(6) | 75,0(4) min | β$^+$ | $^{163}$Ho | 5/2$^−$ | |
| $^{163m}$Er | 445,5(6) keV | 445,5(6) keV | 445,5(6) keV | 580(100) ns | | | (11/2$^−$) | |
| $^{164}$Er | 68 | 96 | 163,929200(3) | stabiel | stabiel | stabiel | 0$^+$ | 0,01601(3) |
| $^{165}$Er | 68 | 97 | 164,930726(3) | 10,36(4) uur | EV | $^{165}$Ho | 5/2$^−$ | |
| $^{166}$Er | 68 | 98 | 165,9302931(27) | stabiel | stabiel | stabiel | 0$^+$ | 0,33503(36) |
| $^{167}$Er | 68 | 99 | 166,9320482(27) | stabiel | stabiel | stabiel | 7/2$^+$ | 0,22869(9) |
| $^{167m}$Er | 207,801(5) keV | 207,801(5) keV | 207,801(5) keV | 2,269(6) s | IT | $^{167}$Er | 1/2$^−$ | |
| $^{168}$Er | 68 | 100 | 167,9323702(27) | stabiel | stabiel | stabiel | 0$^+$ | 0,26978(18) |
| $^{169}$Er | 68 | 101 | 168,9345904(27) | 9,392(18) dagen | β$^−$ | $^{169}$Tm | 1/2$^−$ | |
| $^{170}$Er | 68 | 102 | 169,9354643(30) | stabiel | stabiel | stabiel | 0$^+$ | 0,14910(36) |
| $^{171}$Er | 68 | 103 | 170,9380298(30) | 7,516(2) uur | β$^−$ | $^{171}$Tm | 5/2$^−$ | |
| $^{171m}$Er | 198,6(1) keV | 198,6(1) keV | 198,6(1) keV | 210(10) ns | | | 1/2$^−$ | |
| $^{172}$Er | 68 | 104 | 171,939356(5) | 49,3(3) uur | β$^−$ | $^{172}$Tm | 0$^+$ | |
| $^{173}$Er | 68 | 105 | 172,94240(21) | 1,434(17) min | β$^−$ | $^{173}$Tm | (7/2$^−$) | |
| $^{174}$Er | 68 | 106 | 173,94423(32) | 3,2(2) min | β$^−$ | $^{174}$Tm | 0$^+$ | |
| $^{175}$Er | 68 | 107 | 174,94777(43) | 1,2(3) min | β$^−$ | $^{175}$Tm | (9/2$^+$) | |
| $^{176}$Er | 68 | 108 | 175,95008(43) | 20 s | β$^−$ | $^{176}$Tm | 0$^+$ | |
| $^{177}$Er | 68 | 109 | 176,95405(54) | 3 s | β$^−$ | $^{177}$Tm | 1/2$^−$ | |

## Overzicht van isotopen per element

* (en) R.B. Firestone, S.Y. Frank Chu & C.M. Baglin (1999) - Table of Isotopes (online versie van de cd-rom)
* (en) G. Audi, A.H. Wapstra, C. Thibault, J. Blachot & O. Bersillon (2003) - The NUBASE evaluation of nuclear and decay properties, Nuclear Physics A, 729, pp. 3-128
* (en) J.R. de Laeter, J.K. Böhlke, P. De Bièvre, H. Hidaka, H.S. Peiser, K.J.R. Rosman & P.D.P. Taylor (2003) - Atomic weights of the elements. Review 2000 (IUPAC Technical Report), Pure and Applied Chemistry, 75 (6), pp. 683–800
* (en) M.E. Wieser (2006) - Atomic weights of the elements 2005 (IUPAC Technical Report), Pure and Applied Chemistry, 78 (11), pp. 2051–2066
* (en) David R. Lide (2004) - CRC Handbook of Chemistry and Physics (85th ed.), hoofdstuk 11, CRC Press - ISBN 978-0849304859
$^{142}$Er · $^{143}$Er · $^{144}$Er · $^{145}$Er · $^{146}$Er · $^{147}$Er · $^{147m}$Er · $^{148}$Er · $^{149}$Er · $^{149m1}$Er · $^{149m2}$Er · $^{149m3}$Er · $^{150}$Er · $^{151}$Er · $^{151m1}$Er · $^{151m2}$Er · $^{152}$Er · $^{153}$Er · $^{154}$Er · $^{155}$Er · $^{156}$Er · $^{157}$Er · $^{157m}$Er · $^{158}$Er · $^{159}$Er · $^{159m1}$Er · $^{159m2}$Er · $^{160}$Er · $^{161}$Er · $^{161m}$Er · $^{162}$Er · $^{163}$Er · $^{163m}$Er · $^{164}$Er · $^{165}$Er · $^{166}$Er · $^{167}$Er · $^{167m}$Er · $^{168}$Er · $^{169}$Er · $^{170}$Er · $^{171}$Er · $^{171m}$Er · $^{172}$Er · $^{173}$Er · $^{174}$Er · $^{175}$Er · $^{176}$Er · $^{177}$Er · $^{178}$Er