Naturally occurring scandium (21Sc) is composed of one stable isotope, 45Sc. Twenty-five radioisotopes have been characterized, with the most stable being 46Sc with a half-life of 83.8 days, 47Sc with a half-life of 3.35 days, and 48Sc with a half-life of 43.7 hours and 44Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound 39Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being 44m2Sc (t1/2 58.6 h).
The isotopes of scandium range in atomic weight from 39 u (39Sc) to 62 u (62Sc). The primary decay mode at masses lower than the only stable isotope, 45Sc, is beta-plus or electron capture, and the primary mode at masses above it is beta-minus. The primary decay products at atomic weights below 45Sc are calcium isotopes and the primary products from higher atomic weights are titanium isotopes.
|-| 39Sc| style="text-align:right" | 21| style="text-align:right" | 18| 38.984790(26)| <300 ns| p| 38Ca| (7/2−)#||-| rowspan=3|40Sc| rowspan=3 style="text-align:right" | 21| rowspan=3 style="text-align:right" | 19| rowspan=3|39.977967(3)| rowspan=3|182.3(7) ms| β+ (99.54%)| 40Ca| rowspan=3|4−| rowspan=3||-| β+, p (.44%)| 39K|-| β+, α (.017%)| 36Ar|-| 41Sc| style="text-align:right" | 21| style="text-align:right" | 20| 40.96925113(24)| 596.3(17) ms| β+| 41Ca| 7/2−||-| 42Sc| style="text-align:right" | 21| style="text-align:right" | 21| 41.96551643(29)| 681.3(7) ms| β+| 42Ca| 0+||-| style="text-indent:1em" | 42mSc| colspan="3" style="text-indent:2em" | 616.28(6) keV| 61.7(4) s| β+| 42Ca| (7, 5, 6)+||-| 43Sc| style="text-align:right" | 21| style="text-align:right" | 22| 42.9611507(20)| 3.891(12) h| β+| 43Ca| 7/2−||-| style="text-indent:1em" | 43m1Sc| colspan="3" style="text-indent:2em" | 151.4(2) keV| 438(7) μs||| 3/2+||-| style="text-indent:1em" | 43m2Sc| colspan="3" style="text-indent:2em" | 3123.2(3) keV| 470(4) ns||| (19/2)−||-| 44Sc| style="text-align:right" | 21| style="text-align:right" | 23| 43.9594028(19)| 3.97(4) h| β+| 44Ca| 2+||-| style="text-indent:1em" | 44m1Sc| colspan="3" style="text-indent:2em" | 67.8680(14) keV| 154.2(8) ns||| 1−||-| rowspan=2 style="text-indent:1em" | 44m2Sc| rowspan=2 colspan="3" style="text-indent:2em" | 270.95(20) keV| rowspan=2|58.61(10) h| IT (98.8%)| 44Sc| rowspan=2| 6+| rowspan=2| |-| β+ (1.2%)| 44Ca|-| style="text-indent:1em" | 44m3Sc| colspan="3" style="text-indent:2em" | 146.224(22) keV| 50.4(7) μs||| 0−||-| 45Sc| style="text-align:right" | 21| style="text-align:right" | 24| 44.9559119(9)| colspan=3 align=center|Stable| 7/2−| 1.0000|-| style="text-indent:1em" | 45mSc| colspan="3" style="text-indent:2em" | 12.40(5) keV| 318(7) ms| IT| 45Sc| 3/2+||-| 46Sc| style="text-align:right" | 21| style="text-align:right" | 25| 45.9551719(9)| 83.79(4) d| β−| 46Ti| 4+||-| style="text-indent:1em" | 46m1Sc| colspan="3" style="text-indent:2em" | 52.011(1) keV| 9.4(8) μs||| 6+||-| style="text-indent:1em" | 46m2Sc| colspan="3" style="text-indent:2em" | 142.528(7) keV| 18.75(4) s| IT| 46Sc| 1−||-| 47Sc| style="text-align:right" | 21| style="text-align:right" | 26| 46.9524075(22)| 3.3492(6) d| β−| 47Ti| 7/2−||-| style="text-indent:1em" | 47mSc| colspan="3" style="text-indent:2em" | 766.83(9) keV| 272(8) ns||| (3/2)+||-| 48Sc| style="text-align:right" | 21| style="text-align:right" | 27| 47.952231(6)| 43.67(9) h| β−| 48Ti| 6+||-| 49Sc| style="text-align:right" | 21| style="text-align:right" | 28| 48.950024(4)| 57.2(2) min| β−| 49Ti| 7/2−||-| 50Sc| style="text-align:right" | 21| style="text-align:right" | 29| 49.952188(17)| 102.5(5) s| β−| 50Ti| 5+||-| rowspan=2 style="text-indent:1em" | 50mSc| rowspan=2 colspan="3" style="text-indent:2em" | 256.895(10) keV| rowspan=2|350(40) ms| IT (97.5%)| 50Sc| rowspan=2|2+, 3+| rowspan=2||-| β− (2.5%)| 50Ti|-| 51Sc| style="text-align:right" | 21| style="text-align:right" | 30| 50.953603(22)| 12.4(1) s| β−| 51Ti| (7/2)−||-| 52Sc| style="text-align:right" | 21| style="text-align:right" | 31| 51.95668(21)| 8.2(2) s| β−| 52Ti| 3(+)||-| rowspan=2|53Sc| rowspan=2 style="text-align:right" | 21| rowspan=2 style="text-align:right" | 32| rowspan=2|52.95961(32)#| rowspan=2|2.4(0.6) s| β− (>99.9%)| 53Ti| rowspan=2|(7/2−)#| rowspan=2||-| β−, n (<.1%)| 52Ti|-| rowspan=2|54Sc| rowspan=2 style="text-align:right" | 21| rowspan=2 style="text-align:right" | 33| rowspan=2|53.96326(40)| rowspan=2|260(30) ms| β− (>99.9%)| 54Ti| rowspan=2|3+#| rowspan=2||-| β−, n (<.1%)| 53Ti|-| style="text-indent:1em" | 54mSc| colspan="3" style="text-indent:2em" | 110(3) keV| 7(5) μs||| (5+)||-| rowspan=2|55Sc| rowspan=2 style="text-align:right" | 21| rowspan=2 style="text-align:right" | 34| rowspan=2|54.96824(79)| rowspan=2|0.115(15) s| β− (>99.9%)| 55Ti| rowspan=2|7/2−#| rowspan=2||-| β−, n (<.1%)| 54Ti|-| 56Sc| style="text-align:right" | 21| style="text-align:right" | 35| 55.97287(75)#| 35(5) ms| β−| 56Ti| (1+)||-| 57Sc| style="text-align:right" | 21| style="text-align:right" | 36| 56.97779(75)#| 13(4) ms| β−| 57Ti| 7/2−#||-| 58Sc| style="text-align:right" | 21| style="text-align:right" | 37| 57.98371(86)#| 12(5) ms| β−| 58Ti| (3+)#||-| rowspan=2|59Sc| rowspan=2 style="text-align:right" | 21| rowspan=2 style="text-align:right" | 38| rowspan=2|58.98922(97)#| rowspan=2|10# ms| β−, n| 58Ti| rowspan=2|7/2−#| rowspan=2||-| β−| 59Ti|-| rowspan=3|60Sc| rowspan=3 style="text-align:right" | 21| rowspan=3 style="text-align:right" | 39| rowspan=3|59.99571(97)#| rowspan=3|3# ms
(>620 ns)| β−| 60Ti| rowspan=3|3+#| rowspan=3||-| β−, n| 59Ti|-| β−, 2n| 58Ti|-| rowspan=3|61Sc| rowspan=3 style="text-align:right" | 21| rowspan=3 style="text-align:right" | 40| rowspan=3|61.001(600)#| rowspan=3|2# ms
(>620 ns)| β−| 61Ti| rowspan=3|7/2-#| rowspan=3||-| β−, n| 60Ti|-| β−, 2n| 59Ti|-| rowspan=3|62Sc[1] | rowspan=3 style="text-align:right" | 21| rowspan=3 style="text-align:right" | 41| rowspan=3|62.00785(64)#| rowspan=3|2# ms
(>400 ns)| β−?[2] | 62Ti| rowspan=3|| rowspan=3||-| β−, n?[2] | 61Ti|-| β−, 2n?[2] | 60Ti