# Isotopen van thorium

Het chemisch element thorium (Th), met een atoommassa van 232,03806(2) u, bezit geen stabiele isotopen en wordt dus geclassificeerd als radioactief element. De 29 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 $^{227}$Th, $^{228}$Th, $^{230}$Th, $^{231}$Th en $^{234}$Th voor. De isotoop $^{232}$Th, met een halfwaardetijd van meer dan 14 miljard jaar, komt echter het meest voor: de natuurlijke abundantie bedraagt quasi 100%. Daarom zou thorium beschouwd kunnen worden als een mononuclidisch element.
De kortstlevende isotoop van thorium is $^{209}$Th, met een halfwaardetijd van ongeveer 7 milliseconden. De langstlevende is $^{232}$Th, met een halfwaardetijd van 14,05 miljard jaar.

## Overzicht

| Nuclide | Z (p) | N (n) | Isotopische massa (u) | Halveringstijd | Radioactief verval | VP | Kernspin | Isotopische verhouding (molfractie) |
| Natuurlijk voorkomen (molfractie) |||
| $^{209}$Th | 90 | 119 | 209,01772(11) | 7(5) ms | | | 5/2$^−$ | |
| $^{210}$Th | 90 | 120 | 210,015075(27) | 17(11) ms | α | $^{206}$Ra | 0$^+$ | |
| $^{210}$Th | 90 | 120 | 210,015075(27) | 17(11) ms | β$^+$ (zelden) | $^{210}$Ac | 0$^+$ | |
| $^{211}$Th | 90 | 121 | 211,01493(8) | 48(20) ms | α | $^{207}$Ra | 5/2$^−$ | |
| $^{211}$Th | 90 | 121 | 211,01493(8) | 48(20) ms | β$^+$ (zelden) | $^{211}$Ac | 5/2$^−$ | |
| $^{212}$Th | 90 | 122 | 212,01298(2) | 36(15) ms | α (99,7%) | $^{208}$Ra | 0$^+$ | |
| $^{212}$Th | 90 | 122 | 212,01298(2) | 36(15) ms | β$^+$ (0,3%) | $^{212}$Ac | 0$^+$ | |
| $^{213}$Th | 90 | 123 | 213,01301(8) | 140(25) ms | α | $^{209}$Ra | 5/2$^−$ | |
| $^{213}$Th | 90 | 123 | 213,01301(8) | 140(25) ms | β$^+$ (zelden) | $^{213}$Ac | 5/2$^−$ | |
| $^{214}$Th | 90 | 124 | 214,011500(18) | 100(25) ms | α | $^{210}$Ra | 0$^+$ | |
| $^{215}$Th | 90 | 125 | 215,011730(29) | 1,2(2) s | α | $^{211}$Ra | (1/2$^−$) | |
| $^{216}$Th | 90 | 126 | 216,011062(14) | 26,8(3) ms | α (99,99%) | $^{212}$Ra | 0$^+$ | |
| $^{216}$Th | 90 | 126 | 216,011062(14) | 26,8(3) ms | β$^+$ (0,006%) | $^{216}$Ac | 0$^+$ | |
| $^{216m1}$Th | 2042(13) keV | 2042(13) keV | 2042(13) keV | 137(4) µs | | | (8$^+$) | |
| $^{216m2}$Th | 2637(20) keV | 2637(20) keV | 2637(20) keV | 615(55) ns | | | (11$^−$) | |
| $^{217}$Th | 90 | 127 | 217,013114(22) | 240(5) µs | α | $^{213}$Ra | (9/2$^+$) | |
| $^{218}$Th | 90 | 128 | 218,013284(14) | 109(13) ns | α | $^{214}$Ra | 0$^+$ | |
| $^{219}$Th | 90 | 129 | 219,01554(5) | 1,05(3) µs | α | $^{215}$Ra | 9/2$^+$ | |
| $^{219}$Th | 90 | 129 | 219,01554(5) | 1,05(3) µs | β$^+$ (10$^{−7}$%) | $^{219}$Ac | 9/2$^+$ | |
| $^{220}$Th | 90 | 130 | 220,015748(24) | 9,7(6) µs | α | $^{216}$Ra | 0$^+$ | |
| $^{220}$Th | 90 | 130 | 220,015748(24) | 9,7(6) µs | EV (2 × 10$^{−7}$%) | $^{220}$Ac | 0$^+$ | |
| $^{221}$Th | 90 | 131 | 221,018184(10) | 1,73(3) ms | α | $^{217}$Ra | (7/2$^+$) | |
| $^{222}$Th | 90 | 132 | 222,018468(13) | 2,237(13) ms | α | $^{218}$Ra | 0$^+$ | |
| $^{222}$Th | 90 | 132 | 222,018468(13) | 2,237(13) ms | EV (1,3 × 10$^{−8}$%) | $^{222}$Ac | 0$^+$ | |
| $^{223}$Th | 90 | 133 | 223,020811(10) | 0,60(2) s | α | $^{219}$Ra | 5/2$^+$ | |
| $^{224}$Th | 90 | 134 | 224,021467(12) | 1,05(2) s | α | $^{220}$Ra | 0$^+$ | |
| $^{224}$Th | 90 | 134 | 224,021467(12) | 1,05(2) s | β$^+$β$^+$ (zelden) | $^{224}$Ra | 0$^+$ | |
| $^{225}$Th | 90 | 135 | 225,023951(5) | 8,72(4) min | α (90%) | $^{221}$Ra | 3/2$^+$ | |
| $^{225}$Th | 90 | 135 | 225,023951(5) | 8,72(4) min | EV (10%) | $^{225}$Ac | 3/2$^+$ | |
| $^{226}$Th | 90 | 136 | 226,024903(5) | 30,57(10) min | α | $^{222}$Ra | 0$^+$ | |
| $^{227}$Th | 90 | 137 | 227,0277041(27) | 18,68(9) dagen | α | $^{223}$Ra | 1/2$^+$ | sporen |
| $^{228}$Th | 90 | 138 | 228,0287411(24) | 1,9116(16) jaar | α | $^{224}$Ra | 0$^+$ | sporen |
| $^{228}$Th | 90 | 138 | 228,0287411(24) | 1,9116(16) jaar | CV (1,3 × 10$^{−11}$%) | $^{208}$Pb, $^{20}$O | 0$^+$ | sporen |
| $^{229}$Th | 90 | 139 | 229,031762(3) | 7,34(16) × 10$^3$ jaar | α | $^{225}$Ra | 5/2$^+$ | |
| $^{229m}$Th | 0,0076(5) keV | 0,0076(5) keV | 0,0076(5) keV | 70(50) uur | IT | $^{229}$Th | 3/2$^+$ | |
| $^{230}$Th | 90 | 140 | 230,0331338(19) | 7,538(30) × 10$^4$ jaar | α | $^{226}$Ra | 0$^+$ | sporen |
| $^{230}$Th | 90 | 140 | 230,0331338(19) | 7,538(30) × 10$^4$ jaar | CV (5,6 × 10$^{−11}$%) | $^{206}$Hg, $^{24}$Ne | 0$^+$ | sporen |
| $^{230}$Th | 90 | 140 | 230,0331338(19) | 7,538(30) × 10$^4$ jaar | SS (5 × 10$^{−11}$%) | | 0$^+$ | sporen |
| $^{231}$Th | 90 | 141 | 231,0363043(19) | 25,52(1) uur | β$^−$ | $^{231}$Pa | 5/2$^+$ | sporen |
| $^{231}$Th | 90 | 141 | 231,0363043(19) | 25,52(1) uur | α (10$^{−8}$%) | $^{227}$Ra | 5/2$^+$ | sporen |
| $^{232}$Th | 90 | 142 | 232,0380553(21) | 1,405(6) × 10$^{10}$ jaar | α | $^{228}$Ra | 0$^+$ | 1,0000 |
| $^{232}$Th | 90 | 142 | 232,0380553(21) | 1,405(6) × 10$^{10}$ jaar | β$^−$β$^−$ (zelden) | $^{232}$U | 0$^+$ | 1,0000 |
| $^{232}$Th | 90 | 142 | 232,0380553(21) | 1,405(6) × 10$^{10}$ jaar | SS (1,1 × 10$^{−9}$%) | | 0$^+$ | 1,0000 |
| $^{232}$Th | 90 | 142 | 232,0380553(21) | 1,405(6) × 10$^{10}$ jaar | CV (2,78 × 10$^{−10}$%) | $^{182}$Yb, $^{26}$Ne, $^{24}$Ne | 0$^+$ | 1,0000 |
| $^{233}$Th | 90 | 143 | 233,0415818(21) | 21,83(4) min | β$^−$ | $^{233}$Pa | 1/2$^+$ | |
| $^{234}$Th | 90 | 144 | 234,043601(4) | 24,10(3) d | β$^−$ | $^{234}$Pa | 0$^+$ | sporen |
| $^{235}$Th | 90 | 145 | 235,04751(5) | 7,2(1) min | β$^−$ | $^{235}$Pa | (1/2$^+$) | |
| $^{236}$Th | 90 | 146 | 236,04987(21) | 37,5(2) min | β$^−$ | $^{236}$Pa | 0$^+$ | |
| $^{237}$Th | 90 | 147 | 237,05389(39) | 4,8(5) min | β$^−$ | $^{237}$Pa | 5/2$^+$ | |
| $^{238}$Th | 90 | 148 | 238,0565(3) | 9,4(20) min | β$^−$ | $^{238}$Pa | 0$^+$ | |

## 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
$^{208}$Th · $^{209}$Th · $^{210}$Th · $^{211}$Th · $^{212}$Th · $^{213}$Th · $^{214}$Th · $^{215}$Th · $^{216}$Th · $^{216m1}$Th · $^{216m2}$Th · $^{217}$Th · $^{218}$Th · $^{219}$Th · $^{220}$Th · $^{221}$Th · $^{222}$Th · $^{223}$Th · $^{224}$Th · $^{225}$Th · $^{226}$Th · $^{227}$Th · $^{228}$Th · $^{229}$Th · $^{229m}$Th · $^{230}$Th · $^{231}$Th · $^{232}$Th · $^{233}$Th · $^{234}$Th · $^{235}$Th · $^{236}$Th · $^{237}$Th · $^{238}$Th · $^{239}$Th