Isotopes of scandium

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).

Isotopes of scandium (21Sc)
Main isotopes[1] Decay
abun­dance half-life (t1/2) mode pro­duct
44m2Sc synth 58.61 h IT 44Sc
γ 44Sc
ε 44Ca
45Sc 100% stable
46Sc synth 83.79 d β 46Ti
γ
47Sc synth 80.38 h β 47Ti
γ
48Sc synth 43.67 h β 48Ti
γ
Standard atomic weight Ar°(Sc)
  • 44.955907±0.000004
  • 44.956±0.001 (abridged)[2][3]

The isotopes of scandium range in atomic weight from 38 u (36Sc) 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.

List of isotopes

Nuclide
[n 1]
Z N Isotopic mass (Da)
[n 2][n 3]
Half-life
[n 4]
Decay
mode

[n 5]
Daughter
isotope

[n 6]
Spin and
parity
[n 7][n 4]
Natural abundance (mole fraction)
Excitation energy Normal proportion Range of variation
39Sc 21 18 38.984790(26) <300 ns p 38Ca (7/2−)#
40Sc 21 19 39.977967(3) 182.3(7) ms β+ (99.54%) 40Ca 4-
β+, p (.44%) 39K
β+, α (.017%) 36Ar
41Sc 21 20 40.96925113(24) 596.3(17) ms β+ 41Ca 7/2−
42Sc 21 21 41.96551643(29) 681.3(7) ms β+ 42Ca 0+
42mSc 616.28(6) keV 61.7(4) s β+ 42Ca (7, 5, 6)+
43Sc 21 22 42.9611507(20) 3.891(12) h β+ 43Ca 7/2−
43m1Sc 151.4(2) keV 438(7) μs 3/2+
43m2Sc 3123.2(3) keV 470(4) ns (19/2)−
44Sc 21 23 43.9594028(19) 3.97(4) h β+ 44Ca 2+
44m1Sc 67.8680(14) keV 154.2(8) ns 1−
44m2Sc 270.95(20) keV 58.61(10) h IT (98.8%) 44Sc 6+
β+ (1.2%) 44Ca
44m3Sc 146.224(22) keV 50.4(7) μs 0-
45Sc 21 24 44.9559119(9) Stable 7/2− 1.0000
45mSc 12.40(5) keV 318(7) ms IT 45Sc 3/2+
46Sc 21 25 45.9551719(9) 83.79(4) d β 46Ti 4+
46m1Sc 52.011(1) keV 9.4(8) μs 6+
46m2Sc 142.528(7) keV 18.75(4) s IT 46Sc 1−
47Sc 21 26 46.9524075(22) 3.3492(6) d β 47Ti 7/2−
47mSc 766.83(9) keV 272(8) ns (3/2)+
48Sc 21 27 47.952231(6) 43.67(9) h β 48Ti 6+
49Sc 21 28 48.950024(4) 57.2(2) min β 49Ti 7/2−
50Sc 21 29 49.952188(17) 102.5(5) s β 50Ti 5+
50mSc 256.895(10) keV 350(40) ms IT (97.5%) 50Sc 2+, 3+
β (2.5%) 50Ti
51Sc 21 30 50.953603(22) 12.4(1) s β 51Ti (7/2)−
52Sc 21 31 51.95668(21) 8.2(2) s β 52Ti 3(+)
53Sc 21 32 52.95961(32)# 2.4(0.6) s β (>99.9%) 53Ti (7/2−)#
β, n (<.1%) 52Ti
54Sc 21 33 53.96326(40) 260(30) ms β (>99.9%) 54Ti 3+#
β, n (<.1%) 53Ti
54mSc 110(3) keV 7(5) μs (5+)
55Sc 21 34 54.96824(79) 0.115(15) s β (>99.9%) 55Ti 7/2−#
β, n (<.1%) 54Ti
56Sc 21 35 55.97287(75)# 35(5) ms β 56Ti (1+)
57Sc 21 36 56.97779(75)# 13(4) ms β 57Ti 7/2−#
58Sc 21 37 57.98371(86)# 12(5) ms β 58Ti (3+)#
59Sc 21 38 58.98922(97)# 10# ms β, n 58Ti 7/2−#
β 59Ti
60Sc 21 39 59.99571(97)# 3# ms
(>620 ns)
β 60Ti 3+#
β, n 59Ti
β, 2n 58Ti
61Sc 21 40 61.001(600)# 2# ms
(>620 ns)
β 61Ti 7/2-#
β, n 60Ti
β, 2n 59Ti
62Sc[4] 21 41 62.00785(64)# 2# ms
(>400 ns)
β?[n 8] 62Ti
β, n?[n 8] 61Ti
β, 2n?[n 8] 60Ti
This table header & footer:
  1. mSc  Excited nuclear isomer.
  2. ()  Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. #  Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. #  Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  5. Modes of decay:
    IT:Isomeric transition
    n:Neutron emission
    p:Proton emission
  6. Bold symbol as daughter  Daughter product is stable.
  7. () spin value  Indicates spin with weak assignment arguments.
  8. Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.

References

  1. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. "Standard Atomic Weights: Scandium". CIAAW. 2021.
  3. Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  4. Tarasov, O. B.; et al. (11 July 2018). "Discovery of 60 Ca and Implications For the Stability of 70 Ca". Physical Review Letters. 121 (2): 022501. doi:10.1103/PhysRevLett.121.022501. PMID 30085743.
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