# Isotopen van radium

Het chemisch element radium (Ra), met een atoommassa van ongeveer 226 u, bezit geen stabiele isotopen en wordt dus geclassificeerd als radioactief element. De 32 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 $^{223}$Ra, $^{224}$Ra, $^{226}$Ra en $^{228}$Ra voor.
De kortstlevende isotoop van radium is $^{199}$Ra, met een halfwaardetijd van ongeveer 2,6 milliseconden. De langstlevende is $^{226}$Ra, met een halfwaardetijd van 1600 jaar. Het is deze isotoop, die in de vervalreeks van uranium-238 voorkomt, die in 1898 werd ontdekt door Marie Curie en haar man Pierre Curie.

## Overzicht

| Nuclide | Z (p) | N (n) | Isotopische massa (u) | Halveringstijd | Radioactief verval | VP | Kernspin | Isotopische verhouding (molfractie) |
| Natuurlijk voorkomen (molfractie) |||
| $^{202}$Ra | 88 | 114 | 202,00989(7) | 2,6(21) ms | | | 0$^+$ | |
| $^{203}$Ra | 88 | 115 | 203,00927(9) | 4(3) ms | α | $^{199}$Rn | (3/2$^−$) | |
| $^{203}$Ra | 88 | 115 | 203,00927(9) | 4(3) ms | β$^+$ (zelden) | $^{203}$Fr | (3/2$^−$) | |
| $^{203m}$Ra | 220(90) keV | 220(90) keV | 220(90) keV | 41(17) ms | α | $^{199}$Rn | (13/2$^+$) | |
| $^{203m}$Ra | 220(90) keV | 220(90) keV | 220(90) keV | 41(17) ms | β$^+$ (zelden) | $^{203}$Fr | (13/2$^+$) | |
| $^{204}$Ra | 88 | 116 | 204,006500(17) | 60(11) ms | α (99,7%) | $^{200}$Rn | 0$^+$ | |
| $^{204}$Ra | 88 | 116 | 204,006500(17) | 60(11) ms | β$^+$ (0,3%) | $^{204}$Fr | 0$^+$ | |
| $^{205}$Ra | 88 | 117 | 205,00627(9) | 220(40) ms | α | $^{201}$Rn | (3/2$^−$) | |
| $^{205}$Ra | 88 | 117 | 205,00627(9) | 220(40) ms | β$^+$ (zelden) | $^{205}$Fr | (3/2$^−$) | |
| $^{205m}$Ra | 310(110) keV | 310(110) keV | 310(110) keV | 180(50) ms | α | $^{201}$Rn | (13/2$^+$) | |
| $^{205m}$Ra | 310(110) keV | 310(110) keV | 310(110) keV | 180(50) ms | IT (zelden) | $^{205}$Ra | (13/2$^+$) | |
| $^{206}$Ra | 88 | 118 | 206,003827(19) | 0,24(2) s | α | $^{202}$Rn | 0$^+$ | |
| $^{207}$Ra | 88 | 119 | 207,00380(6) | 1,3(2) s | α (90%) | $^{203}$Rn | (5/2$^−$, 3/2$^−$) | |
| $^{207}$Ra | 88 | 119 | 207,00380(6) | 1,3(2) s | β$^+$ (10%) | $^{207}$Fr | (5/2$^−$, 3/2$^−$) | |
| $^{207m}$Ra | 560(50) keV | 560(50) keV | 560(50) keV | 57(8) ms | IT (85%) | $^{207}$Ra | (13/2$^+$) | |
| $^{207m}$Ra | 560(50) keV | 560(50) keV | 560(50) keV | 57(8) ms | α (15%) | $^{203}$Rn | (13/2$^+$) | |
| $^{207m}$Ra | 560(50) keV | 560(50) keV | 560(50) keV | 57(8) ms | β$^+$ (0,55%) | $^{207}$Fr | (13/2$^+$) | |
| $^{208}$Ra | 88 | 120 | 208,001840(17) | 1,3(2) s | α (95%) | $^{204}$Rn | 0$^+$ | |
| $^{208}$Ra | 88 | 120 | 208,001840(17) | 1,3(2) s | β$^+$ (5%) | $^{208}$Fr | 0$^+$ | |
| $^{208m}$Ra | 1800(200) keV | 1800(200) keV | 1800(200) keV | 270 ns | | | (8$^+$) | |
| $^{209}$Ra | 88 | 121 | 209,00199(5) | 4,6(2) s | α (90%) | $^{205}$Rn | 5/2$^−$ | |
| $^{209}$Ra | 88 | 121 | 209,00199(5) | 4,6(2) s | β$^+$ (10%) | $^{209}$Fr | 5/2$^−$ | |
| $^{210}$Ra | 88 | 122 | 210,000495(16) | 3,7(2) s | α (96%) | $^{206}$Rn | 0$^+$ | |
| $^{210}$Ra | 88 | 122 | 210,000495(16) | 3,7(2) s | β$^+$ (4%) | $^{210}$Fr | 0$^+$ | |
| $^{210m}$Ra | 1800(200) keV | 1800(200) keV | 1800(200) keV | 2,24 µs | | | (8$^+$) | |
| $^{211}$Ra | 88 | 123 | 211,000898(28) | 13(2) s | α (97%) | $^{207}$Rn | 5/2$^−$ | |
| $^{211}$Ra | 88 | 123 | 211,000898(28) | 13(2) s | β$^+$ (3%) | $^{211}$Fr | 5/2$^−$ | |
| $^{212}$Ra | 88 | 124 | 211,999794(12) | 13,0(2) s | α (85%) | $^{208}$Rn | 0$^+$ | |
| $^{212}$Ra | 88 | 124 | 211,999794(12) | 13,0(2) s | β$^+$ (15%) | $^{212}$Fr | 0$^+$ | |
| $^{212m1}$Ra | 1958,4(5) keV | 1958,4(5) keV | 1958,4(5) keV | 10,9(4) µs | | | 8$^+$ | |
| $^{212m2}$Ra | 2613,4(5) keV | 2613,4(5) keV | 2613,4(5) keV | 0,85(13) µs | | | 11$^−$ | |
| $^{213}$Ra | 88 | 125 | 213,000384(22) | 2,74(6) min | α (80%) | $^{209}$Rn | 1/2$^−$ | |
| $^{213}$Ra | 88 | 125 | 213,000384(22) | 2,74(6) min | β$^+$ (20%) | $^{213}$Fr | 1/2$^−$ | |
| $^{213m}$Ra | 1769(6) keV | 1769(6) keV | 1769(6) keV | 2,1(1) ms | IT (99%) | $^{213}$Ra | 17/2$^−$ | |
| $^{213m}$Ra | 1769(6) keV | 1769(6) keV | 1769(6) keV | 2,1(1) ms | α (1%) | $^{209}$Rn | 17/2$^−$ | |
| $^{214}$Ra | 88 | 126 | 214,000108(10) | 2,46(3) s | α (99,94%) | $^{210}$Rn | 0$^+$ | |
| $^{214}$Ra | 88 | 126 | 214,000108(10) | 2,46(3) s | β$^+$ (0,06%) | $^{214}$Fr | 0$^+$ | |
| $^{215}$Ra | 88 | 127 | 215,002720(8) | 1,55(7) ms | α | $^{211}$Rn | (9/2$^+$) | |
| $^{215m1}$Ra | 1877,8(5) keV | 1877,8(5) keV | 1877,8(5) keV | 7,1(2) µs | | | (25/2$^+$) | |
| $^{215m2}$Ra | 2246,9(5) keV | 2246,9(5) keV | 2246,9(5) keV | 1,39(7) µs | | | (29/2$^−$) | |
| $^{215m3}$Ra | 3756,6(6)$^+$X keV | 3756,6(6)$^+$X keV | 3756,6(6)$^+$X keV | 0,555(10) µs | | | (43/2$^−$) | |
| $^{216}$Ra | 88 | 128 | 216,003533(9) | 182(10) ns | α | $^{212}$Rn | 0$^+$ | |
| $^{216}$Ra | 88 | 128 | 216,003533(9) | 182(10) ns | EV (1 × 10$^{−8}$%) | $^{216}$Fr | 0$^+$ | |
| $^{217}$Ra | 88 | 129 | 217,006320(9) | 1,63(17) µs | α | $^{213}$Rn | (9/2$^+$) | |
| $^{218}$Ra | 88 | 130 | 218,007140(12) | 25,2(3) µs | α | $^{214}$Rn | 0$^+$ | |
| $^{218}$Ra | 88 | 130 | 218,007140(12) | 25,2(3) µs | β$^+$β$^+$ (zelden) | $^{218}$Rn | 0$^+$ | |
| $^{219}$Ra | 88 | 131 | 219,010085(9) | 10(3) ms | α | $^{215}$Rn | 7/2$^+$ | |
| $^{220}$Ra | 88 | 132 | 220,011028(10) | 17,9(14) ms | α | $^{216}$Rn | 0$^+$ | |
| $^{221}$Ra | 88 | 133 | 221,013917(5) | 28(2) s | α | $^{217}$Rn | 5/2$^+$ | |
| $^{221}$Ra | 88 | 133 | 221,013917(5) | 28(2) s | CV (1,2 × 10$^{−10}$%) | $^{207}$Pb, $^{14}$C | 5/2$^+$ | |
| $^{222}$Ra | 88 | 134 | 222,015375(5) | 38,0(5) s | α | $^{218}$Rn | 0$^+$ | |
| $^{222}$Ra | 88 | 134 | 222,015375(5) | 38,0(5) s | CV (3 × 10$^{−8}$%) | $^{208}$Pb, $^{14}$C | 0$^+$ | |
| $^{223}$Ra | 88 | 135 | 223,0185022(27) | 11,43(5) dagen | α | $^{219}$Rn | 3/2$^+$ | sporen |
| $^{223}$Ra | 88 | 135 | 223,0185022(27) | 11,43(5) dagen | CV (6,4 × 10$^{−8}$%) | $^{209}$Pb, $^{14}$C | 3/2$^+$ | sporen |
| $^{224}$Ra | 88 | 136 | 224,0202118(24) | 3,6319(23) dagen | α | $^{220}$Rn | 0$^+$ | sporen |
| $^{224}$Ra | 88 | 136 | 224,0202118(24) | 3,6319(23) dagen | CV (4,3 × 10$^{−9}$%) | $^{210}$Pb, $^{14}$C | 0$^+$ | sporen |
| $^{225}$Ra | 88 | 137 | 225,023612(3) | 14,9(2) dagen | β$^−$ | $^{225}$Ac | 1/2$^+$ | |
| $^{226}$Ra | 88 | 138 | 226,0254098(25) | 1600(7) jaar | α | $^{222}$Rn | 0$^+$ | sporen |
| $^{226}$Ra | 88 | 138 | 226,0254098(25) | 1600(7) jaar | β$^−$β$^−$ (zelden) | $^{226}$Th | 0$^+$ | sporen |
| $^{226}$Ra | 88 | 138 | 226,0254098(25) | 1600(7) jaar | CV (2,6 × 10$^{−9}$%) | $^{212}$Pb, $^{14}$C | 0$^+$ | sporen |
| $^{227}$Ra | 88 | 139 | 227,0291778(25) | 42,2(5) min | β$^−$ | $^{227}$Ac | 3/2$^+$ | |
| $^{228}$Ra | 88 | 140 | 228,0310703(26) | 5,75(3) y | β$^−$ | $^{228}$Ac | 0$^+$ | sporen |
| $^{229}$Ra | 88 | 141 | 229,034958(20) | 4,0(2) min | β$^−$ | $^{229}$Ac | 5/2($^+$) | |
| $^{230}$Ra | 88 | 142 | 230,037056(13) | 93(2) min | β$^−$ | $^{230}$Ac | 0$^+$ | |
| $^{231}$Ra | 88 | 143 | 231,04122(32) | 103(3) s | β$^−$ | $^{231}$Ac | (5/2$^+$) | |
| $^{231m}$Ra | 66,21(9) keV | 66,21(9) keV | 66,21(9) keV | ± 53 µs | | | (1/2$^+$) | |
| $^{232}$Ra | 88 | 144 | 232,04364(30) | 250(50) s | β$^−$ | $^{232}$Ac | 0$^+$ | |
| $^{233}$Ra | 88 | 145 | 233,04806(50) | 30(5) s | β$^−$ | $^{233}$Ac | 1/2$^+$ | |
| $^{234}$Ra | 88 | 146 | 234,05070(53) | 30(10) s | β$^−$ | $^{234}$Ac | 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
$^{201}$Ra · $^{202}$Ra · $^{203}$Ra · $^{203m}$Ra · $^{204}$Ra · $^{205}$Ra · $^{205m}$Ra · $^{206}$Ra · $^{207}$Ra · $^{207m}$Ra · $^{208}$Ra · $^{208m}$Ra · $^{209}$Ra · $^{210}$Ra · $^{210m}$Ra · $^{211}$Ra · $^{212}$Ra · $^{212m1}$Ra · $^{212m2}$Ra · $^{213}$Ra · $^{213m}$Ra · $^{214}$Ra · $^{215}$Ra · $^{215m1}$Ra · $^{215m2}$Ra · $^{215m3}$Ra · $^{216}$Ra · $^{217}$Ra · $^{218}$Ra · $^{219}$Ra · $^{220}$Ra · $^{221}$Ra · $^{222}$Ra · $^{223}$Ra · $^{224}$Ra · $^{225}$Ra · $^{226}$Ra · $^{227}$Ra · $^{228}$Ra · $^{229}$Ra · $^{230}$Ra · $^{231}$Ra · $^{231m}$Ra · $^{232}$Ra · $^{233}$Ra · $^{234}$Ra · $^{235}$Ra