Isotopes of scandium

Isotopes of scandium (₂₁Sc)
γ	44Sc
ε	44Ca
γ	–
γ	–
γ	–
Standard atomic weight Ar°(Sc)
	44.955907±0.000004; 44.956±0.001 (abridged)[2][3];

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 (t_1/2 58.6 h).

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)
Nuclide [n 1]	Excitation energy			Half-life [n 4]	Decay mode [n 5]	Daughter isotope [n 6]	Spin and parity [n 7][n 4]	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+
^44m2Sc	270.95(20) keV			58.61(10) h	β⁺ (1.2%)	⁴⁴Ca	6+
^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+
^50mSc	256.895(10) keV			350(40) ms	β⁻ (2.5%)	⁵⁰Ti	2+, 3+
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−)#
⁵³Sc	21	32	52.95961(32)#	2.4(0.6) s	β⁻, n (<.1%)	⁵²Ti	(7/2−)#
⁵⁴Sc	21	33	53.96326(40)	260(30) ms	β⁻ (>99.9%)	⁵⁴Ti	3+#
⁵⁴Sc	21	33	53.96326(40)	260(30) ms	β⁻, n (<.1%)	⁵³Ti	3+#
^54mSc	110(3) keV			7(5) μs			(5+)
⁵⁵Sc	21	34	54.96824(79)	0.115(15) s	β⁻ (>99.9%)	⁵⁵Ti	7/2−#
⁵⁵Sc	21	34	54.96824(79)	0.115(15) s	β⁻, n (<.1%)	⁵⁴Ti	7/2−#
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−#
⁵⁹Sc	21	38	58.98922(97)#	10# ms	β⁻	⁵⁹Ti	7/2−#
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:

^mSc – Excited nuclear isomer.
( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
# – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
# – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
Modes of decay:

IT: Isomeric transition

n: Neutron emission

p: Proton emission
Bold symbol as daughter – Daughter product is stable.
( ) spin value – Indicates spin with weak assignment arguments.
Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.

References

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.
"Standard Atomic Weights: Scandium". CIAAW. 2021.
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.
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.

Audi, G.; Kondev, F.G.; Wang, M.; Huang, W.J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. doi:10.1088/1674-1137/41/3/030001.
Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.

"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

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[4] Sc – Excited nuclear isomer.

[5] ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-6] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[TNN-7] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[8] Modes of decay:

IT: Isomeric transition

n: Neutron emission

p: Proton emission

[9] Bold symbol as daughter – Daughter product is stable.

[10] ( ) spin value – Indicates spin with weak assignment arguments.

[decay_mode_1-12] Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.

[NUBASE2020-1] 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.

[CIAAW2021-3] 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.

[11] 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.