Isotopes of titanium

Naturally occurring titanium (₂₂Ti) is composed of five stable isotopes; ⁴⁶Ti, ⁴⁷Ti, ⁴⁸Ti, ⁴⁹Ti and ⁵⁰Ti with ⁴⁸Ti being the most abundant (73.8% natural abundance). Twenty-one radioisotopes have been characterized, with the most stable being ⁴⁴Ti with a half-life of 60 years, ⁴⁵Ti with a half-life of 184.8 minutes, ⁵¹Ti with a half-life of 5.76 minutes, and ⁵²Ti with a half-life of 1.7 minutes. All of the remaining radioactive isotopes have half-lives that are less than 33 seconds, and the majority of these have half-lives that are less than half a second.^[4]

Isotopes of titanium (₂₂Ti)

Main isotopes[1] Decay abun­dance half-life (t1/2) mode pro­duct 44Ti synth 59.1 y ε 44Sc 46Ti 8.25% stable 47Ti 7.44% stable 48Ti 73.7% stable 49Ti 5.41% stable 50Ti 5.18% stable
Standard atomic weight Ar°(Ti)
	47.867±0.001[2] 47.867±0.001 (abridged)[3]
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The isotopes of titanium range in atomic mass from 39.00 u (³⁹Ti) to 64.00 u (⁶⁴Ti). The primary decay mode for isotopes lighter than the stable isotopes (lighter than ⁴⁶Ti) is β⁺ and the primary mode for the heavier ones (heavier than ⁵⁰Ti) is β⁻; their respective decay products are scandium isotopes and the primary products after are vanadium isotopes.^[4]

List of isotopes

Nuclide [n 1]	Z	N	Isotopic mass (Da)[5] [n 2][n 3]	Half-life[1] [n 4]	Decay mode[1] [n 5]	Daughter isotope [n 6]	Spin and parity[1] [n 7][n 4]	Natural abundance (mole fraction)
	Excitation energy							Normal proportion[1]	Range of variation
39Ti	22	17	39.00268(22)#	28.5(9) ms	β+, p (93.7%)	38Ca	3/2+#
					β+ (~6.3%)	39Sc
					β+, 2p (?%)	37K
40Ti	22	18	39.990345(73)	52.4(3) ms	β+, p (95.8%)	39Ca	0+
					β+ (4.2%)	40Sc
41Ti	22	19	40.983148(30)	81.9(5) ms	β+, p (91.1%)	40Ca	3/2+
					β+ (8.9%)	41Sc
42Ti	22	20	41.97304937(29)	208.3(4) ms	β+	42Sc	0+
43Ti	22	21	42.9685284(61)	509(5) ms	β+	43Sc	7/2−
43m1Ti	313.0(10) keV			11.9(3) μs	IT	43Ti	(3/2+)
43m2Ti	3066.4(10) keV			556(6) ns	IT	43Ti	(19/2−)
44Ti	22	22	43.95968994(75)	59.1(3) y	EC	44Sc	0+
45Ti	22	23	44.95812076(90)	184.8(5) min	β+	45Sc	7/2−
45mTi	36.53(15) keV			3.0(2) μs	IT	45Ti	3/2−
46Ti	22	24	45.952626356(97)	Stable			0+	0.0825(3)
47Ti	22	25	46.951757491(85)	Stable			5/2−	0.0744(2)
48Ti	22	26	47.947940677(79)	Stable			0+	0.7372(3)
49Ti	22	27	48.947864391(84)	Stable			7/2−	0.0541(2)
50Ti	22	28	49.944785.622(88)	Stable			0+	0.0518(2)
51Ti	22	29	50.94660947(52)	5.76(1) min	β−	51V	3/2−
52Ti	22	30	51.9468835(29)	1.7(1) min	β−	52V	0+
53Ti	22	31	52.9496707(31)	32.7(9) s	β−	53V	(3/2)−
54Ti	22	32	53.950892(17)	2.1(10) s	β−	54V	0+
55Ti	22	33	54.955091(31)	1.3(1) s	β−	55V	(1/2)−
56Ti	22	34	55.95768(11)	200(5) ms	β−	56V	0+
57Ti	22	35	56.96307(22)	95(8) ms	β−	57V	5/2−#
58Ti	22	36	57.96681(20)	55(6) ms	β−	58V	0+
59Ti	22	37	58.97222(32)#	28.5(19) ms	β−	59V	5/2−#
59mTi	108.5(5) keV			615(11) ns	IT	59Ti	1/2−#
60Ti	22	38	59.97628(26)	22.2(16) ms	β−	60V	0+
61Ti	22	39	60.98243(32)#	15(4) ms	β−	61V	1/2−#
61m1Ti	125.0(5) keV			200(28) ns	IT	61Ti	5/2−#
61m2Ti	700.1(7) keV			354(69) ns	IT	61Ti	9/2+#
62Ti	22	40	61.98690(43)#	9# ms [>620 ns]			0+
63Ti	22	41	62.99371(54)#	10# ms [>620 ns]			1/2−#
64Ti	22	42	63.99841(64)#	5# ms [>620 ns]			0+
This table header & footer: view

1. ^mTi – 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:

   EC:	Electron capture
   n:	Neutron emission
   p:	Proton emission

6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.

Titanium-44

Titanium-44 (⁴⁴Ti) is a radioactive isotope of titanium that undergoes electron capture to an excited state of scandium-44 with a half-life of 60 years, before the ground state of ⁴⁴Sc and ultimately ⁴⁴Ca are populated.^[6] Because titanium-44 can only undergo electron capture, its half-life increases with ionization and it becomes stable in its fully ionized state (that is, having a charge of +22).^[7]

Titanium-44 is produced in relative abundance in the alpha process in stellar nucleosynthesis and the early stages of supernova explosions.^[8] It is produced when calcium-40 fuses with an alpha particle (helium-4 nucleus) in a star's high-temperature environment; the resulting ⁴⁴Ti nucleus can then fuse with another alpha particle to form chromium-48. The age of supernovae may be determined through measurements of gamma-ray emissions from titanium-44 and its abundance.^[7] It was observed in the Cassiopeia A supernova remnant and SN 1987A at a relatively high concentration, a consequence of delayed decay resulting from ionizing conditions.^[6][7]

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: Titanium". CIAAW. 1993.
3. Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (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. Barbalace, Kenneth L. (2006). "Periodic Table of Elements: Ti - Titanium". Retrieved 2006-12-26.
5. Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
6. Motizuki, Y.; Kumagai, S. (2004). "Radioactivity of the key isotope ⁴⁴Ti in SN 1987A". AIP Conference Proceedings. 704 (1): 369–374. arXiv:astro-ph/0312620. Bibcode:2004AIPC..704..369M. CiteSeerX 10.1.1.315.8412. doi:10.1063/1.1737130. S2CID 1700673.
7. Mochizuki, Y.; Takahashi, K.; Janka, H.-Th.; Hillebrandt, W.; Diehl, R. (2008). "Titanium-44: Its effective decay rate in young supernova remnants, and its abundance in Cas A". Astronomy and Astrophysics. 346 (3): 831–842. arXiv:astro-ph/9904378.
8. Fryer, C.; Dimonte, G.; Ellinger, E.; Hungerford, A.; Kares, B.; Magkotsios, G.; Rockefeller, G.; Timmes, F.; Woodward, P.; Young, P. (2011). Nucleosynthesis in the Universe, Understanding ⁴⁴Ti (PDF). ADTSC Science Highlights (Report). Los Alamos National Laboratory. pp. 42–43.

• 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.