Isotopes of titanium
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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-three radioisotopes have been characterized, with the most stable being 44Ti with a half-life of 59.1 years and 45Ti with a half-life of 184.8 minutes. All of the remaining radioactive isotopes have half-lives that are less than 10 minutes, and the majority of these have half-lives that are less than one second.
The isotopes of titanium range from 39Ti to 64Ti. The primary decay mode for isotopes lighter than the stable isotopes is β+ and the primary mode for the heavier ones is β−; the decay products are respectively scandium isotopes and vanadium isotopes.
There are two stable isotopes of titanium with an odd number of nucleons, 47Ti and 49Ti, which thus have non-zero nuclear spin of 5/2− and 7/2− (respectively) and are NMR-active.[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 | 49.944785622(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+ | ||||||||||||||
| 65Ti[6] | 22 | 43 | 65.00559(75)# | 1# ms | 1/2−# | ||||||||||||||
| 66Ti[6] | 22 | 44 | 0+ | ||||||||||||||||
| This table header & footer: | |||||||||||||||||||
- mTi – 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:
EC: Electron capture n: Neutron emission p: Proton emission - Bold symbol as daughter – Daughter product is stable.
- ( ) spin value – Indicates spin with weak assignment arguments.
Titanium-44
Titanium-44 (44Ti) is a radioactive isotope of titanium that undergoes electron capture with a half-life of 59.1 years to an excited state of scandium-44, before reaching the ground state of 44Sc and ultimately of 44Ca.[7] Because titanium-44 can decay only through electron capture, its half-life increases slowly with its ionization state and it becomes stable in its fully ionized state (that is, having a charge of +22),[8] though as astrophysical environments never lack electrons completely, it will always decay.
Titanium-44 is produced in relative abundance in the alpha process in stellar nucleosynthesis and the early stages of supernova explosions.[9] It is produced when stable calcium-40 adds an alpha particle (helium-4), as nickel-56 is the result of adding three more. The age of supernova remnants (even though nickel-56 has died away to iron) may be determined through measurements of gamma-ray emissions from the relatively long-lived titanium-44 and of its abundance.[8] It was observed in the Cassiopeia A supernova remnant and SN 1987A at a relatively high concentration, enhanced by the delayed decay in the ionizing conditions.[7]
See also
Daughter products other than titanium