# Isotopen van actinium

Het chemisch element actinium (Ac), met een atoommassa van ongeveer 227 u, bezit geen stabiele isotopen en wordt dus geclassificeerd als radioactief element. De 31 radio-isotopen zijn onstabiel en hebben een relatief korte halfwaardetijd (de meeste minder dan een seconde). In de natuur komen sporen van de radio-isotopen $^{227}$Ac en het veel zeldzamere $^{228}$Ac voor.
De kortstlevende isotoop van actinium is $^{206}$Ac, met een halfwaardetijd van ongeveer 25 milliseconden. De langstlevende is $^{227}$Ac, met een halfwaardetijd van 21,772 jaar.

## Overzicht

| Nuclide | Z (p) | N (n) | Isotopische massa (u) | Halveringstijd | Radioactief verval | VP | Kernspin | Isotopische verhouding (molfractie) |
| Natuurlijk voorkomen (molfractie) |||
| $^{206}$Ac | 89 | 117 | 206,01450(8) | 25(7) ms | | | (3$^+$) | |
| $^{206m1}$Ac | 80(50) keV | 80(50) keV | 80(50) keV | 15(6) ms | | | | |
| $^{206m2}$Ac | 290(110) keV | 290(110) keV | 290(110) keV | 41(16) ms | | | (10$^−$) | |
| $^{207}$Ac | 89 | 118 | 207,01195(6) | 31(8) ms | α | $^{203}$Fr | 9/2$^−$ | |
| $^{208}$Ac | 89 | 119 | 208,01155(6) | 97(16) ms | α (99%) | $^{204}$Fr | (3$^+$) | |
| $^{208}$Ac | 89 | 119 | 208,01155(6) | 97(16) ms | β$^+$ (1%) | $^{208}$Ra | (3$^+$) | |
| $^{208m}$Ac | 506(26) keV | 506(26) keV | 506(26) keV | 28(7) ms | α (89%) | $^{204}$Fr | (10$^−$) | |
| $^{208m}$Ac | 506(26) keV | 506(26) keV | 506(26) keV | 28(7) ms | IT (10%) | $^{208}$Ac | (10$^−$) | |
| $^{208m}$Ac | 506(26) keV | 506(26) keV | 506(26) keV | 28(7) ms | β$^+$ (1%) | $^{208}$Ra | (10$^−$) | |
| $^{209}$Ac | 89 | 120 | 209,00949(5) | 92(11) ms | α (99%) | $^{205}$Fr | (9/2$^−$) | |
| $^{209}$Ac | 89 | 120 | 209,00949(5) | 92(11) ms | β$^+$ (1%) | $^{209}$Ra | (9/2$^−$) | |
| $^{210}$Ac | 89 | 121 | 210,00944(6) | 350(40) ms | α (96%) | $^{206}$Fr | 7$^+$ | |
| $^{210}$Ac | 89 | 121 | 210,00944(6) | 350(40) ms | β$^+$ (4%) | $^{210}$Ra | 7$^+$ | |
| $^{211}$Ac | 89 | 122 | 211,00773(8) | 213(25) ms | α (99,8%) | $^{207}$Fr | 9/2$^−$ | |
| $^{211}$Ac | 89 | 122 | 211,00773(8) | 213(25) ms | β$^+$ (0,2%) | $^{211}$Ra | 9/2$^−$ | |
| $^{212}$Ac | 89 | 123 | 212,00781(7) | 920(50) ms | α (97%) | $^{208}$Fr | 6$^+$ | |
| $^{212}$Ac | 89 | 123 | 212,00781(7) | 920(50) ms | β$^+$ (3%) | $^{212}$Ra | 6$^+$ | |
| $^{213}$Ac | 89 | 124 | 213,00661(6) | 731(17) ms | α | $^{209}$Fr | (9/2$^−$) | |
| $^{213}$Ac | 89 | 124 | 213,00661(6) | 731(17) ms | β$^+$ (zelden) | $^{213}$Ra | (9/2$^−$) | |
| $^{214}$Ac | 89 | 125 | 214,006902(24) | 8,2(2) s | α (89%) | $^{210}$Fr | (5$^+$) | |
| $^{214}$Ac | 89 | 125 | 214,006902(24) | 8,2(2) s | β$^+$ (11%) | $^{214}$Ra | (5$^+$) | |
| $^{215}$Ac | 89 | 126 | 215,006454(23) | 0,17(1) s | α (99,91%) | $^{211}$Fr | 9/2$^−$ | |
| $^{215}$Ac | 89 | 126 | 215,006454(23) | 0,17(1) s | β$^+$ (0,09%) | $^{215}$Ra | 9/2$^−$ | |
| $^{216}$Ac | 89 | 127 | 216,008720(29) | 0,440(16) ms | α | $^{212}$Fr | (1$^−$) | |
| $^{216}$Ac | 89 | 127 | 216,008720(29) | 0,440(16) ms | β$^+$ (7 × 10$^{−5}$%) | $^{216}$Ra | (1$^−$) | |
| $^{216m}$Ac | 44(7) keV | 44(7) keV | 44(7) keV | 443(7) µs | | | (9$^−$) | |
| $^{217}$Ac | 89 | 128 | 217,009347(14) | 69(4) ns | α (98%) | $^{213}$Fr | 9/2$^−$ | |
| $^{217}$Ac | 89 | 128 | 217,009347(14) | 69(4) ns | β$^+$ (2%) | $^{217}$Ra | 9/2$^−$ | |
| $^{217m}$Ac | 2012(20) keV | 2012(20) keV | 2012(20) keV | 740(40) ns | | | 29/2$^+$ | |
| $^{218}$Ac | 89 | 129 | 218,01164(5) | 1,08(9) µs | α | $^{214}$Fr | (1$^−$) | |
| $^{218m}$Ac | 584(50) keV | 584(50) keV | 584(50) keV | 103(11) ns | | | (11$^+$) | |
| $^{219}$Ac | 89 | 130 | 219,01242(5) | 11,8(15) µs | α | $^{215}$Fr | 9/2$^−$ | |
| $^{219}$Ac | 89 | 130 | 219,01242(5) | 11,8(15) µs | β$^+$ (10$^{−6}$%) | $^{219}$Ra | 9/2$^−$ | |
| $^{220}$Ac | 89 | 131 | 220,014763(16) | 26,36(19) ms | α | $^{216}$Fr | (3$^−$) | |
| $^{220}$Ac | 89 | 131 | 220,014763(16) | 26,36(19) ms | β$^+$ (5 × 10$^{−4}$%) | $^{220}$Ra | (3$^−$) | |
| $^{221}$Ac | 89 | 132 | 221,01559(5) | 52(2) ms | α | $^{217}$Fr | 9/2$^−$ | |
| $^{222}$Ac | 89 | 133 | 222,017844(6) | 5,0(5) s | α (99%) | $^{218}$Fr | 1$^−$ | |
| $^{222}$Ac | 89 | 133 | 222,017844(6) | 5,0(5) s | β$^+$ (1%) | $^{222}$Ra | 1$^−$ | |
| $^{222m}$Ac | 200(150) keV | 200(150) keV | 200(150) keV | 1,05(7) min | α (88,6%) | $^{218}$Fr | | |
| $^{222m}$Ac | 200(150) keV | 200(150) keV | 200(150) keV | 1,05(7) min | IT (10%) | $^{222}$Ac | | |
| $^{222m}$Ac | 200(150) keV | 200(150) keV | 200(150) keV | 1,05(7) min | β$^+$ (1,4%) | $^{222}$Ra | | |
| $^{223}$Ac | 89 | 134 | 223,019137(8) | 2,10(5) min | α (99%) | $^{219}$Fr | (5/2$^−$) | |
| $^{223}$Ac | 89 | 134 | 223,019137(8) | 2,10(5) min | EV (1%) | $^{223}$Ra | (5/2$^−$) | |
| $^{223}$Ac | 89 | 134 | 223,019137(8) | 2,10(5) min | CV (3,2 × 10$^{−9}$%) | $^{209}$Bi, $^{14}$C | (5/2$^−$) | |
| $^{224}$Ac | 89 | 135 | 224,021723(4) | 2,78(17) uur | β$^+$ (90,9%) | $^{224}$Ra | 0$^−$ | |
| $^{224}$Ac | 89 | 135 | 224,021723(4) | 2,78(17) uur | α (9,1%) | $^{220}$Fr | 0$^−$ | |
| $^{224}$Ac | 89 | 135 | 224,021723(4) | 2,78(17) uur | β$^−$ (1,6%) | $^{224}$Th | 0$^−$ | |
| $^{225}$Ac | 89 | 136 | 225,023230(5) | 10,0(1) dagen | α | $^{221}$Fr | (3/2$^−$) | |
| $^{225}$Ac | 89 | 136 | 225,023230(5) | 10,0(1) dagen | CV (6 × 10$^{−10}$%) | $^{211}$Bi, $^{14}$C | (3/2$^−$) | |
| $^{226}$Ac | 89 | 137 | 226,026098(4) | 29,37(12) uur | β$^−$ (83%) | $^{226}$Th | (1$^−$) | |
| $^{226}$Ac | 89 | 137 | 226,026098(4) | 29,37(12) uur | EV (17%) | $^{226}$Ra | (1$^−$) | |
| $^{226}$Ac | 89 | 137 | 226,026098(4) | 29,37(12) uur | α (,006%) | $^{222}$Fr | (1$^−$) | |
| $^{227}$Ac | 89 | 138 | 227,0277521(26) | 21,772(3) jaar | β$^−$ (98,61%) | $^{227}$Th | 3/2$^−$ | Sporen |
| $^{227}$Ac | 89 | 138 | 227,0277521(26) | 21,772(3) jaar | α (1,38%) | $^{223}$Fr | 3/2$^−$ | Sporen |
| $^{228}$Ac | 89 | 139 | 228,0310211(27) | 6,15(2) uur | β$^−$ | $^{228}$Th | 3$^+$ | Sporen |
| $^{228}$Ac | 89 | 139 | 228,0310211(27) | 6,15(2) uur | α (5,5 × 10$^{−6}$%) | $^{224}$Fr | 3$^+$ | Sporen |
| $^{229}$Ac | 89 | 140 | 229,03302(4) | 62,7(5) min | β$^−$ | $^{229}$Th | (3/2$^+$) | |
| $^{230}$Ac | 89 | 141 | 230,03629(32) | 122(3) s | β$^−$ | $^{230}$Th | (1$^+$) | |
| $^{231}$Ac | 89 | 142 | 231,03856(11) | 7,5(1) min | β$^−$ | $^{231}$Th | (1/2$^+$) | |
| $^{232}$Ac | 89 | 143 | 232,04203(11) | 119(5) s | β$^−$ | $^{232}$Th | (1$^+$) | |
| $^{233}$Ac | 89 | 144 | 233,04455(32) | 145(10) s | β$^−$ | $^{233}$Th | (1/2$^+$) | |
| $^{234}$Ac | 89 | 145 | 234,04842(43) | 44(7) s | β$^−$ | $^{234}$Th | | |
| $^{235}$Ac | 89 | 146 | 235,05123(38) | 40 s | β$^−$ | $^{235}$Th | 1/2$^+$ | |
| $^{236}$Ac | 89 | 147 | 236,05530(54) | 2 min | β$^−$ | $^{236}$Th | | |

## 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
$^{205}$Ac · $^{206}$Ac · $^{206m1}$Ac · $^{206m2}$Ac · $^{207}$Ac · $^{208}$Ac · $^{208m}$Ac · $^{209}$Ac · $^{210}$Ac · $^{211}$Ac · $^{212}$Ac · $^{213}$Ac · $^{214}$Ac · $^{215}$Ac · $^{216}$Ac · $^{216m}$Ac · $^{217}$Ac · $^{217m}$Ac · $^{218}$Ac · $^{218m}$Ac · $^{219}$Ac · $^{220}$Ac · $^{221}$Ac · $^{222}$Ac · $^{222m}$Ac · $^{223}$Ac · $^{224}$Ac · $^{225}$Ac · $^{226}$Ac · $^{227}$Ac · $^{228}$Ac · $^{229}$Ac · $^{230}$Ac · $^{231}$Ac · $^{232}$Ac · $^{233}$Ac · $^{234}$Ac · $^{235}$Ac · $^{236}$Ac · $^{237}$Ac