釓（原子質量單位：15725 3）有 6 種穩定同位素（154Gd、155Gd、156Gd、157Gd、158Gd、160Gd）和 1 种放射性同位素（152Gd）存在於自然界，其中丰度 2484 的 158Gd 最常見。160Gd 理論上可以雙 β 衰變，但目前尚未觀測到，半衰期至少 13 年。 圖表 134Gd styletextalignright 64 styletextalignright 70 13395537 43 04 s 0 135Gd styletextalignright 64 styletextalignright 71 13495257 54 11 2 s 32 136Gd styletextalignright 64 styletextalignright 72 13594734 43 1 s 200 ns 136Eu rowspan2137Gd rowspan2 styletextalignright 64 rowspan2 styletextalignright 73 rowspan213694502 43 rowspan222 2 s 137Eu rowspan272 rowspan2 rowspan2 （不常見） 136Sm 138Gd styletextalignright 64 styletextalignright 74 13794012 21 47 9 s 138Eu 0 styletextindent1em 138mGd colspan3 styletextindent2em 22327 11 keV 6 1 µs 8 rowspan2139Gd rowspan2 styletextalignright 64 rowspan2 styletextalignright 75 rowspan213893824 21 rowspan257 3 s 139Eu rowspan292 rowspan2 rowspan2 （不常見） 138Sm styletextindent1em 139mGd colspan3 styletextindent2em 250 150 keV 48 9 s 12 140Gd styletextalignright 64 styletextalignright 76 13993367 3 158 4 s 140Eu 0 rowspan2141Gd rowspan2 styletextalignright 64 rowspan2 styletextalignright 77 rowspan2140932126 21 rowspan214 4 s 9997 141Eu rowspan212 rowspan2 rowspan2 03 140Sm rowspan2 styletextindent1em 141mGd rowspan2 colspan3 styletextindent2em 3778 2 keV rowspan2245 5 s 89 141Eu rowspan2112 rowspan2 rowspan2 IT 11 141Gd 142Gd styletextalignright 64 styletextalignright 78 14192812 3 702 6 s 142Eu 0 rowspan3143Gd rowspan3 styletextalignright 64 rowspan3 styletextalignright 79 rowspan314292675 22 rowspan339 2 s 143Eu rowspan312 rowspan3 rowspan3 （不常見） 139Pm （不常見） 142Sm rowspan3 styletextindent1em 143mGd rowspan3 colspan3 styletextindent2em 1526 5 keV rowspan31100 14 s 143Eu rowspan3112 rowspan3 rowspan3 （不常見） 139Pm （不常見） 142Sm 144Gd styletextalignright 64 styletextalignright 80 14392296 3 447 6 min 144Eu 0 145Gd styletextalignright 64 styletextalignright 81 144921709 20 230 4 min 145Eu 12 rowspan2 styletextindent1em 145mGd rowspan2 colspan3 styletextindent2em 7491 2 keV rowspan285 3 s IT 943 145Gd rowspan2112 rowspan2 rowspan2 57 145Eu 146Gd styletextalignright 64 styletextalignright 82 145918311 5 4827 10 d 146Eu 0 147Gd styletextalignright 64 styletextalignright 83 146919094 3 3806 12 h 147Eu 72 styletextindent1em 147mGd colspan3 styletextindent2em 85878 4 keV 510 20 ns 492 148Gd styletextalignright 64 styletextalignright 84 147918115 3 746 30 a 144Sm 0 rowspan2149Gd rowspan2 styletextalignright 64 rowspan2 styletextalignright 85 rowspan2148919341 4 rowspan2928 10 d 149Eu rowspan272 rowspan2 rowspan2 434104 145Sm 150Gd styletextalignright 64 styletextalignright 86 149918659 7 179 8106 a 146Sm 0 rowspan2151Gd rowspan2 styletextalignright 64 rowspan2 styletextalignright 87 rowspan2150920348 4 rowspan2124 1 d 151Eu rowspan272 rowspan2 rowspan2 106 147Sm 152Gdprimordial radionuclide styletextalignright 64 styletextalignright 88 1519197910 27 108 81014 a 148Sm 0 00020 1 153Gd styletextalignright 64 styletextalignright 89 1529217495 27 2404 10 d 153Eu 32 styletextindent1em 153m1Gd colspan3 styletextindent2em 951737 12 keV 35 4 µs 92 styletextindent1em 153m2Gd colspan3 styletextindent2em 171189 5 keV 760 14 µs 112 154Gd styletextalignright 64 styletextalignright 90 1539208656 27 colspan3 styletextaligncenter 觀測上穩定 Believed to undergo decay to 150Smsup 0 00218 3 155GdFission product styletextalignright 64 styletextalignright 91 1549226220 27 colspan3 styletextaligncenter 觀測上穩定 Believed to undergo decay to 151Smsup 32 01480 12 styletextindent1em 155mGd colspan3 styletextindent2em 12105 19 keV 3197 27 ms IT 155Gd 112 156Gd styletextalignright 64 styletextalignright 92 1559221227 27 colspan3 styletextaligncenter 0 02047 9 styletextindent1em 156mGd colspan3 styletextindent2em 213760 5 keV 13 1 µs 7 157Gd styletextalignright 64 styletextalignright 93 1569239601 27 colspan3 styletextaligncenter 32 01565 2 158Gd styletextalignright 64 styletextalignright 94 1579241039 27 colspan3 styletextaligncenter 0 02484 7 159Gd styletextalignright 64 styletextalignright 95 1589263887 27 18479 4 h 159Tb 32 160Gd styletextalignright 64 styletextalignright 96 1599270541 27 colspan3 styletextaligncenter 觀測上穩定 Believed to undergo decay to 160Dy with a halflife over 131021 years 0 02186 19 161Gd styletextalignright 64 styletextalignright 97 1609296692 29 3646 3 min 161Tb 52 162Gd styletextalignright 64 styletextalignright 98 161930985 5 84 2 min 162Tb 0 163Gd styletextalignright 64 styletextalignright 99 16293399 32 68 3 s 163Tb 72 164Gd styletextalignright 64 styletextalignright 100 16393586 43 45 3 s 164Tb 0 165Gd styletextalignright 64 styletextalignright 101 16493938 54 103 16 s 165Tb 12 166Gd styletextalignright 64 styletextalignright 102 16594160 64 48 10 s 166Tb 0 167Gd styletextalignright 64 styletextalignright 103 16694557 64 3 s 167Tb 52 168Gd styletextalignright 64 styletextalignright 104 16794836 75 300 ms 168Tb 0 169Gd styletextalignright 64 styletextalignright 105 16895287 86 1 s 169Tb 72 參考文獻 引用 來源 Isotope masses from Ame2003 Atomic Mass Evaluation by G Audi AH Wapstra C Thibault J Blachot and O Bersillon in Nuclear Physics A729 2003 Isotopic compositions and standard atomic masses from Atomic weights of the elements Review 2000 IUPAC Technical Report Pure Appl Chem Vol 75 No 6 pp 683800 2003 and Atomic Weights Revised 2005 Halflife spin and isomer data selected from these sources Editing notes on this articles talk page Audi Bersillon Blachot Wapstra The Nubase2003 evaluation of nuclear and decay properties Nuc Phys A 729 pp 3128 2003 National Nuclear Data Center Brookhaven National Laboratory Information extracted from the NuDat 21 database retrieved Sept 2005 David R Lide ed Norman E Holden in CRC Handbook of Chemistry and Physics 85th Edition online version CRC Press Boca Raton Florida 2005 Section 11 Table of the Isotopes Gd Category 釓