鈣（原子量：40078 4）共有 24 個同位素，其中有 5 個是穩定的。 圖表 styletextalignright 20 styletextalignright 14 3401412 32 35 ns 33K 0 rowspan2 rowspan2 styletextalignright 20 rowspan2 styletextalignright 15 rowspan23500494 21 rowspan2257 2 ms β 999 35K rowspan212 rowspan2 rowspan2 β p 1 34Ar rowspan2 rowspan2 styletextalignright 20 rowspan2 styletextalignright 16 rowspan23599309 4 rowspan2102 2 ms β p 568 35Ar rowspan20 rowspan2 rowspan2 β 432 36K rowspan2 rowspan2 styletextalignright 20 rowspan2 styletextalignright 17 rowspan236985870 24 rowspan21811 10 ms β p 745 36Ar rowspan232 rowspan2 rowspan2 β 255 37K styletextalignright 20 styletextalignright 18 37976318 5 440 8 ms β 38K 0 styletextalignright 20 styletextalignright 19 389707197 20 8596 14 ms β 39K 32 在質子數和中子數相等，且未觀測到放射性衰變的核素中最重 styletextalignright 20 styletextalignright 20 3996259098 22 colspan3 aligncenter 觀測上穩定被認為會雙電子捕獲成 40Ar，半衰期超過 591021 年 0 096941 156 096933096947 styletextalignright 20 styletextalignright 21 4096227806 26 102 7105 y 41K 72 痕量 styletextalignright 20 styletextalignright 22 4195861801 27 colspan3 aligncenter 穩定 0 000647 23 000646000648 styletextalignright 20 styletextalignright 23 429587666 3 colspan3 aligncenter 穩定 72 000135 10 000135000135 styletextalignright 20 styletextalignright 24 439554818 4 colspan3 aligncenter 穩定 0 002086 110 002082002092 styletextalignright 20 styletextalignright 25 449561866 4 16267 25 d β 45Sc 72 styletextalignright 20 styletextalignright 26 459536926 24 colspan3 aligncenter 觀測上穩定被認為會雙 β 衰變成 46Ti，半衰期超過 281015 年 0 4 3105 41054105 styletextalignright 20 styletextalignright 27 469545460 24 4536 3 d β 47Sc 72 放射性同位素 styletextalignright 20 styletextalignright 28 47952534 4 43 381018 y ββ已知會雙 β 衰變的最輕核素 48Ti 0 000187 21 000186000188 styletextalignright 20 styletextalignright 29 48955674 4 8718 6 min β 49Sc 32 styletextalignright 20 styletextalignright 30 49957519 10 139 6 s β 50Sc 0 rowspan2 rowspan2 styletextalignright 20 rowspan2 styletextalignright 31 rowspan2509615 1 rowspan2100 8 s β 999 51Sc rowspan232 rowspan2 rowspan2 β n 1 50Sc rowspan2 rowspan2 styletextalignright 20 rowspan2 styletextalignright 32 rowspan25196510 75 rowspan246 3 s β 98 52Sc rowspan20 rowspan2 rowspan2 β n 2 51Sc rowspan2 rowspan2 styletextalignright 20 rowspan2 styletextalignright 33 rowspan25297005 54 rowspan290 15 ms β 70 53Sc rowspan232 rowspan2 rowspan2 β n 30 52Sc rowspan2 rowspan2 styletextalignright 20 rowspan2 styletextalignright 34 rowspan25397435 75 rowspan250 ms 300 ns β n 53Sc rowspan20 rowspan2 rowspan2 β 54Sc styletextalignright 20 styletextalignright 35 5498055 75 30 ms 300 ns β 55Sc 52 styletextalignright 20 styletextalignright 36 5598557 97 10 ms 300 ns β 56Sc 0 rowspan2 rowspan2 styletextalignright 20 rowspan2 styletextalignright 37 rowspan25699236 107 rowspan25 ms β 57Sc rowspan252 rowspan2 rowspan2 β n 56Sc styletextalignright 20 styletextalignright 38 57962133 0 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 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 Ca