鋁（原子量：269815384 3）共有 23 個已知同位素，質量數介於 2143 之間，其中只有 1 個是穩定的，其他都具有放射性，因此鋁屬於單一同位素元素。天然存在的鋁同位素有 2 個，分別是穩定的 27Al 和具放射性的 26Al，其中 27Al 佔天然鋁的絕大部分，而 26Al 在自然界中僅痕量存在，為宇宙射線散裂所產生。其他放射性同位素都不出現在自然界中，只有在實驗室製造出來過，且半衰期都很短，非常不穩定。 圖表 21Al styletextalignright 13 styletextalignright 8 2102908 64 20Mg rowspan322Al rowspan3 styletextalignright 13 rowspan3 styletextalignright 9 rowspan32201952 10 rowspan359 3 ms β 967 22Mg rowspan33 rowspan3 β 2p 25 20Ne β p 08 21Na rowspan223Al rowspan2 styletextalignright 13 rowspan2 styletextalignright 10 rowspan223007267 20 rowspan2470 30 ms β 92 23Mg rowspan252 rowspan2 β p 8 22Na rowspan324Al rowspan3 styletextalignright 13 rowspan3 styletextalignright 11 rowspan3239999389 30 rowspan32053 4 s β 9995 24Mg rowspan34 rowspan3 β α 0349 20Ne β p 0159 23Na rowspan3 styletextindent1em 24mAl rowspan3 colspan3 styletextindent2em 4258 1 keV rowspan31313 25 ms IT 82 24Al rowspan31 rowspan3 β 18 24Mg β α 20Ne 25Al styletextalignright 13 styletextalignright 12 249904281 5 7183 12 s β 25Mg 52 用於測定太陽系早期歷史事件和隕石的放射性定年法中 styletextalignright 13 styletextalignright 13 2598689169 6 717 24105 years β 26Mg 5 痕量 styletextindent1em 26mAl colspan3 styletextindent2em 228305 13 keV 63452 19 s β 26Mg 0 styletextalignright 13 styletextalignright 14 2698153863 12 colspan3 styletextaligncenter 52 10000 28Al styletextalignright 13 styletextalignright 15 2798191031 14 22414 12 min β 28Si 3 29Al styletextalignright 13 styletextalignright 16 289804450 13 656 6 min β 29Si 52 30Al styletextalignright 13 styletextalignright 17 29982960 15 360 6 s β 30Si 3 rowspan231Al rowspan2 styletextalignright 13 rowspan2 styletextalignright 18 rowspan230983947 22 rowspan2644 25 ms β 984 31Si rowspan23252 rowspan2 β n 16 30Si rowspan232Al rowspan2 styletextalignright 13 rowspan2 styletextalignright 19 rowspan23198812 9 rowspan2317 8 ms β 993 32Si rowspan21 rowspan2 β n 7 31Si styletextindent1em 32mAl colspan3 styletextindent2em 9557 4 keV 200 20 ns 4 rowspan233Al rowspan2 styletextalignright 13 rowspan2 styletextalignright 20 rowspan23299084 8 rowspan2417 2 ms β 915 33Si rowspan252 rowspan2 β n 85 32Si rowspan234Al rowspan2 styletextalignright 13 rowspan2 styletextalignright 21 rowspan23399685 12 rowspan2563 5 ms β 875 34Si rowspan24 rowspan2 β n 125 33Si rowspan235Al rowspan2 styletextalignright 13 rowspan2 styletextalignright 22 rowspan23499986 19 rowspan2386 4 ms β 74 35Si rowspan252 rowspan2 β n 26 34Si rowspan236Al rowspan2 styletextalignright 13 rowspan2 styletextalignright 23 rowspan23600621 23 rowspan290 40 ms β 69 36Si rowspan2 rowspan2 β n 31 35Si 37Al styletextalignright 13 styletextalignright 24 3701068 36 107 13 ms β 37Si 32 38Al styletextalignright 13 styletextalignright 25 3801723 78 76 6 ms β 38Si 39Al styletextalignright 13 styletextalignright 26 3902297 158 76 16 ms β 39Si 32 40Al styletextalignright 13 styletextalignright 27 4002962 43 10 ms 260 ns β 40Si 41Al styletextalignright 13 styletextalignright 28 4103588 54 2 ms 260 ns β 41Si 52 42Al styletextalignright 13 styletextalignright 29 4204305 64 1 ms 170 ns β 42Si 43Al styletextalignright 13 styletextalignright 30 4305048 86 1 ms 170 ns β 43Si 參考文獻 Isotope masses from Ame2003 Atomic Mass Evaluation by G Audi AH Wapstra C Thibault J Blachot and O Bersillon in Nuclear Physics A729 2003 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 Al Category 鋁