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 (t_1/2 58.6 h).

Main isotopes of scandium (₂₁Sc)

Iso­tope Decay abun­dance half-life (t1/2) mode pro­duct ^44m2Sc syn 58.61 h IT ^44Sc γ ^44Sc ε ^44Ca ^45Sc 100% stable ^46Sc syn 83.79 d β^− ^46Ti γ – ^47Sc syn 80.38 h β^− ^47Ti γ – ^48Sc syn 43.67 h β^− ^48Ti γ –
Standard atomic weight Ar, standard(Sc)	44.955908(5)[1]

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

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.

References

1. Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

• 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. Lay summary.
• 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.