Het chemisch element astaat (At), met een atoommassa van ongeveer 210 u, bezit geen stabiele isotopen en wordt dus geclassificeerd als radioactief element. Er zijn 32 radio-isotopen en nog zo'n 20 metastabiele toestanden. In de natuur komen sporen van de radio-isotopen 215At, 218At en 219At voor.
De kortstlevende isotoop van astaat is 191At, met een halfwaardetijd van ongeveer 1,7 milliseconden. De langstlevende is 210At, met een halfwaardetijd van 8,1 uur. De langstlevende in de natuur voorkomende isotoop is 219At (56 seconden), dat optreedt in de vervalreeks van uranium-235.
Overzicht
| Nuclide | Z (p) | N (n) | Isotopische massa (u) | Halveringstijd | Radioactief verval | VP | Kernspin | Isotopische verhouding (molfractie) |
Natuurlijk voorkomen (molfractie) |
|---|---|---|---|---|---|---|---|---|---|
| Excitatie-energie | |||||||||
| 191At | 85 | 106 | 1,7 ms | (1/2+) | |||||
| 191mAt | 2,1 ms | (7/2−) | |||||||
| 193At | 85 | 108 | 192,99984(6) | 28 ms | α | 189Bi | (1/2+) | ||
| 193m1At | 50 keV | 21(5) ms | (7/2−) | ||||||
| 193m2At | 39 keV | 27 ms | (13/2+) | ||||||
| 194At | 85 | 109 | 193,99873(20) | ± 40 ms | α | 190Bi | 3+ | ||
| β+ (zelden) | 194Po | ||||||||
| 194mAt | 480(190) keV | ± 250 ms | α | 190Bi | 10− | ||||
| IT (zelden) | 194At | ||||||||
| 195At | 85 | 110 | 194,996268(10) | 328(20) ms | α (75%) | 191Bi | (1/2+) | ||
| β+ (25%) | 195Po | ||||||||
| 195mAt | 34(7) keV | 147(5) ms | 9/2− | ||||||
| 196At | 85 | 111 | 195,99579(6) | 253(9) ms | α (96%) | 192Bi | 3+ | ||
| β+ (4%) | 196Po | ||||||||
| 196m1At | −30(80) keV | 20 ms | 10− | ||||||
| 196m2At | 157,9(1) keV | 11 µs | 5+ | ||||||
| 197At | 85 | 112 | 196,99319(5) | 0,390(16) s | α (96%) | 193Bi | (9/2−) | ||
| β+ (4%) | 197Po | ||||||||
| 197mAt | 52(10) keV | 2,0(2) s | (1/2+) | ||||||
| 198At | 85 | 113 | 197,99284(5) | 4,2(3) s | α (94%) | 194Bi | (3+) | ||
| β+ (6%) | 198Po | ||||||||
| 198mAt | 330(90) keV | 1,0(2) s | (10−) | ||||||
| 199At | 85 | 114 | 198,99053(5) | 6,92(13) s | α (89%) | 195Bi | (9/2−) | ||
| β+ (11%) | 199Po | ||||||||
| 200At | 85 | 115 | 199,990351(26) | 43,2(9) s | α (57%) | 196Bi | (3+) | ||
| β+ (43%) | 200Po | ||||||||
| 200m1At | 112,7(30) keV | 47(1) s | α (43%) | 196Bi | (7+) | ||||
| IT | 200At | ||||||||
| β+ | 200Po | ||||||||
| 200m2At | 344(3) keV | 3,5(2) s | (10−) | ||||||
| 201At | 85 | 116 | 200,988417(9) | 85(3) s | α (71%) | 197Bi | (9/2−) | ||
| β+ (29%) | 201Po | ||||||||
| 202At | 85 | 117 | 201,98863(3) | 184(1) s | β+ (88%) | 202Po | (2, 3)+ | ||
| α (12%) | 198Bi | ||||||||
| 202m1At | 190(40) keV | 182(2) s | (7+) | ||||||
| 202m2At | 580(40) keV | 460(50) ms | (10−) | ||||||
| 203At | 85 | 118 | 202,986942(13) | 7,37(13) min | β+ (69%) | 203Po | 9/2− | ||
| α (31%) | 199Bi | ||||||||
| 204At | 85 | 119 | 203,987251(26) | 9,2(2) min | β+ (96,2%) | 204Po | 7+ | ||
| α (3,8%) | 200Bi | ||||||||
| 204mAt | 587,30(20) keV | 108(10) ms | IT | 204At | (10−) | ||||
| 205At | 85 | 120 | 204,986074(16) | 26,2(5) min | β+ (90%) | 205Po | 9/2− | ||
| α (10%) | 201Bi | ||||||||
| 205mAt | 2339,65(23) keV | 7,76(14) µs | 29/2+ | ||||||
| 206At | 85 | 121 | 205,986667(22) | 30,6(13) min | β+ (99,11%) | 206Po | (5)+ | ||
| α (0,89%) | 202Bi | ||||||||
| 206mAt | 807(3) keV | 410(80) ns | 10− | ||||||
| 207At | 85 | 122 | 206,985784(23) | 1,80(4) uur | β+ (91,4%) | 207Po | 9/2− | ||
| α (8,6%) | 203Bi | ||||||||
| 208At | 85 | 123 | 207,986590(28) | 1,63(3) uur | β+ (99,45%) | 208Po | 6+ | ||
| α (0,55%) | 204Bi | ||||||||
| 209At | 85 | 124 | 208,986173(8) | 5,41(5) uur | β+ (95,9%) | 209Po | 9/2− | ||
| α (4,1%) | 205Bi | ||||||||
| 210At | 85 | 125 | 209,987148(8) | 8,1(4) uur | β+ (99,82%) | 210Po | 5+ | ||
| α (0,175%) | 206Bi | ||||||||
| 210m1At | 2549,6(2) keV | 482(6) µs | 15− | ||||||
| 210m2At | 4027,7(2) keV | 5,66(7) µs | 19+ | ||||||
| 211At | 85 | 126 | 210,9874963(30) | 7,214(7) uur | EV (58,2%) | 211Po | 9/2− | ||
| α (41,8%) | 207Bi | ||||||||
| 212At | 85 | 127 | 211,990745(8) | 0,314(2) s | α (99,97%) | 208Bi | (1−) | ||
| β+ (0,03%) | 212Po | ||||||||
| β− (2 × 10−6%) | 212Rn | ||||||||
| 212m1At | 223(7) keV | 0,119(3) s | α (99%) | 208Bi | (9−) | ||||
| IT (1%) | 212At | ||||||||
| 212m2At | 4771,6(11) keV | 152(5) µs | (25−) | ||||||
| 213At | 85 | 128 | 212,992937(5) | 125(6) ns | α | 209Bi | 9/2− | ||
| 214At | 85 | 129 | 213,996372(5) | 558(10) ns | α | 210Bi | 1− | ||
| 214m1At | 59(9) keV | 265(30) ns | |||||||
| 214m2At | 231(6) keV | 760(15) ns | 9− | ||||||
| 215At | 85 | 130 | 214,998653(7) | 0,10(2) ms | α | 211Bi | 9/2− | sporen | |
| 216At | 85 | 131 | 216,002423(4) | 0,30(3) ms | α (99,99%) | 212Bi | 1− | ||
| β− (0,006%) | 216Rn | ||||||||
| EV (3 × 10−7%) | 216Po | ||||||||
| 216mAt | 413(5) keV | 100 µs | (9−) | ||||||
| 217At | 85 | 132 | 217,004719(5) | 32,3(4) ms | α (99,98%) | 213Bi | 9/2− | ||
| β− (0,012%) | 217Rn | ||||||||
| 218At | 85 | 133 | 218,008694(12) | 1,5(3) s | α (99,9%) | 214Bi | 1− | sporen | |
| β− (0,1%) | 218Rn | ||||||||
| 219At | 85 | 134 | 219,011162(4) | 56(3) s | α (97%) | 215Bi | 5/2− | sporen | |
| β− (3%) | 219Rn | ||||||||
| 220At | 85 | 135 | 220,01541(6) | 3,71(4) min | β− (92%) | 220Rn | 3− | ||
| α (8%) | 216Bi | ||||||||
| 221At | 85 | 136 | 221,01805(21) | 2,3(2) min | β− | 221Rn | 3/2− | ||
| 222At | 85 | 137 | 222,02233(32) | 54(10) s | β− | 222Rn | |||
| 223At | 85 | 138 | 223,02519(43) | 50(7) s | 3/2− | ||||
Overzicht van isotopen per element
| 1 | 18 | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | H | 2 | Periodiek systeem | 13 | 14 | 15 | 16 | 17 | He | |||||||||
| 2 | Li | Be | De links verwijzen naar isotopen per element | B | C | N | O | F | Ne | |||||||||
| 3 | Na | Mg | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | Al | Si | P | S | Cl | Ar |
| 4 | K | Ca | Sc | Ti | V | Cr | Mn | Fe | Co | Ni | Cu | Zn | Ga | Ge | As | Se | Br | Kr |
| 5 | Rb | Sr | Y | Zr | Nb | Mo | Tc | Ru | Rh | Pd | Ag | Cd | In | Sn | Sb | Te | I | Xe |
| 6 | Cs | Ba | ↓ | Hf | Ta | W | Re | Os | Ir | Pt | Au | Hg | Tl | Pb | Bi | Po | At | Rn |
| 7 | Fr | Ra | ↓↓ | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og |
| Lanthaniden | La | Ce | Pr | Nd | Pm | Sm | Eu | Gd | Tb | Dy | Ho | Er | Tm | Yb | Lu | |||
| Actiniden | Ac | Th | Pa | U | Np | Pu | Am | Cm | Bk | Cf | Es | Fm | Md | No | Lr | |||
Bronnen, noten en/of referenties
- (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
· 
· 