Isotopes of molybdenum
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Molybdenum (42Mo) has 39 known isotopes, ranging in atomic mass from 81 to 119, as well as four metastable nuclear isomers. Seven isotopes occur naturally, with atomic masses of 92, 94, 95, 96, 97, 98, and 100. All unstable isotopes of molybdenum decay into isotopes of zirconium, niobium, technetium, and ruthenium.[5]
Molybdenum-100, with a half-life of approximately 8.5×1018 y, is the only naturally occurring radioisotope. It undergoes double beta decay into ruthenium-100. Molybdenum-98 is the most common isotope, comprising 24.14% of all molybdenum on Earth. Molybdenum isotopes with mass numbers 111 and up all have half-lives of approximately .15 s.[5]
List of isotopes
Nuclide [n 1] |
Z | N | Isotopic mass (Da)[6] [n 2][n 3] |
Half-life [n 4] |
Daughter isotope [n 6] |
Natural abundance (mole fraction) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Excitation energy | Normal proportion | Range of variation | |||||||||||||||||
81Mo | 42 | 39 | 80.96623(54)# | 1# ms | β+? | 81Nb | 5/2+# | ||||||||||||
β+, p? | 80Zr | ||||||||||||||||||
82Mo | 42 | 40 | 81.95666(43)# | 30# ms | β+? | 82Nb | 0+ | ||||||||||||
β+, p? | 81Zr | ||||||||||||||||||
83Mo | 42 | 41 | 82.95025(43)# | 23(19) ms [6(+30-3) ms] |
β+ | 83Nb | 3/2−# | ||||||||||||
β+, p | 82Zr | ||||||||||||||||||
84Mo | 42 | 42 | 83.94185(32)# | 3.8(9) ms [3.7(+10-8) s] |
β+ | 84Nb | 0+ | ||||||||||||
85Mo | 42 | 43 | 84.938261(17) | 3.2(2) s | β+ | 85Nb | (1/2−)# | ||||||||||||
86Mo | 42 | 44 | 85.931174(3) | 19.6(11) s | β+ | 86Nb | 0+ | ||||||||||||
87Mo | 42 | 45 | 86.928196(3) | 14.05(23) s | β+ (85%) | 87Nb | 7/2+# | ||||||||||||
β+, p (15%) | 86Zr | ||||||||||||||||||
88Mo | 42 | 46 | 87.921968(4) | 8.0(2) min | β+ | 88Nb | 0+ | ||||||||||||
89Mo | 42 | 47 | 88.919468(4) | 2.11(10) min | β+ | 89Nb | (9/2+) | ||||||||||||
89mMo | 387.5(2) keV | 190(15) ms | IT
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89Mo | (1/2−) | ||||||||||||||
90Mo | 42 | 48 | 89.913931(4) | 5.56(9) h | β+ | 90Nb | 0+ | ||||||||||||
90mMo | 2874.73(15) keV | 1.12(5) μs | 8+# | ||||||||||||||||
91Mo | 42 | 49 | 90.911745(7) | 15.49(1) min | β+ | 91Nb | 9/2+ | ||||||||||||
91mMo | 653.01(9) keV | 64.6(6) s | IT (50.1%) | 91Mo | 1/2− | ||||||||||||||
β+ (49.9%) | 91Nb | ||||||||||||||||||
92Mo | 42 | 50 | 91.90680715(17) | Observationally Stable[n 9]
|
0+ | 0.14649(106) | |||||||||||||
92mMo | 2760.46(16) keV | 190(3) ns | 8+ | ||||||||||||||||
93Mo | 42 | 51 | 92.90680877(19) | 4839(63) y[2] | EC | 93Nb | 5/2+ | ||||||||||||
93mMo | 2424.89(3) keV | 6.85(7) h | IT (99.88%) | 93Mo | 21/2+ | ||||||||||||||
β+ (.12%) | 93Nb | ||||||||||||||||||
94Mo | 42 | 52 | 93.90508359(15) | Stable | 0+ | 0.09187(33) | |||||||||||||
95Mo[n 10] | 42 | 53 | 94.90583744(13) | Stable | 5/2+ | 0.15873(30) | |||||||||||||
96Mo | 42 | 54 | 95.90467477(13) | Stable | 0+ | 0.16673(30) | |||||||||||||
97Mo[n 10] | 42 | 55 | 96.90601690(18) | Stable | 5/2+ | 0.09582(15) | |||||||||||||
98Mo[n 10] | 42 | 56 | 97.90540361(19) | Observationally Stable[n 11] | 0+ | 0.24292(80) | |||||||||||||
99Mo[n 10][n 12] | 42 | 57 | 98.90770730(25) | 2.7489(6) d | β− | 99mTc | 1/2+ | ||||||||||||
99m1Mo | 97.785(3) keV | 15.5(2) μs | 5/2+ | ||||||||||||||||
99m2Mo | 684.5(4) keV | 0.76(6) μs | 11/2− | ||||||||||||||||
100Mo[n 13][n 10] | 42 | 58 | 99.9074680(3) | 8.5(5)×1018 a | β−β− | 100Ru | 0+ | 0.09744(65) | |||||||||||
101Mo | 42 | 59 | 100.9103376(3) | 14.61(3) min | β− | 101Tc | 1/2+ | ||||||||||||
102Mo | 42 | 60 | 101.910294(9) | 11.3(2) min | β− | 102Tc | 0+ | ||||||||||||
103Mo | 42 | 61 | 102.913092(10) | 67.5(15) s | β− | 103Tc | (3/2+) | ||||||||||||
104Mo | 42 | 62 | 103.913747(10) | 60(2) s | β− | 104Tc | 0+ | ||||||||||||
105Mo | 42 | 63 | 104.916982(10) | 35.6(16) s | β− | 105Tc | (5/2−) | ||||||||||||
106Mo | 42 | 64 | 105.918273(10) | 8.73(12) s | β− | 106Tc | 0+ | ||||||||||||
107Mo | 42 | 65 | 106.92212(1) | 3.5(5) s | β− | 107Tc | (7/2−) | ||||||||||||
107mMo | 66.3(2) keV | 470(30) ns | (5/2−) | ||||||||||||||||
108Mo | 42 | 66 | 107.924048(10) | 1.09(2) s | β− | 108Tc | 0+ | ||||||||||||
109Mo | 42 | 67 | 108.928438(12) | 0.53(6) s | β− | 109Tc | (7/2−)# | ||||||||||||
110Mo | 42 | 68 | 109.930718(26) | 0.27(1) s | β− (>99.9%) | 110Tc | 0+ | ||||||||||||
β−, n (<.1%) | 109Tc | ||||||||||||||||||
111Mo | 42 | 69 | 110.935652(14) | 200# ms [>300 ns] |
β− | 111Tc | |||||||||||||
112Mo | 42 | 70 | 111.93829(22)# | 150# ms [>300 ns] |
β− | 112Tc | 0+ | ||||||||||||
113Mo | 42 | 71 | 112.94348(32)# | 100# ms [>300 ns] |
β− | 113Tc | |||||||||||||
114Mo | 42 | 72 | 113.94667(32)# | 80# ms [>300 ns] |
0+ | ||||||||||||||
115Mo | 42 | 73 | 114.95217(43)# | 60# ms [>300 ns] |
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116Mo | 42 | 74 | 115.95576(54)# | 32(4) ms | β− | 116Tc | 0+ | ||||||||||||
117Mo | 42 | 75 | 116.96169(54)# | 22(5) ms | β− | 117Tc | 3/2+# | ||||||||||||
118Mo | 42 | 76 | 117.96525(54)# | 21(6) ms | β− | 118Tc | 0+ | ||||||||||||
119Mo | 42 | 77 | 118.97147(32)# | 12# ms | β−? | 119Tc | 3/2+# | ||||||||||||
β−, n? | 118Tc | ||||||||||||||||||
β−, 2n? | 117Tc | ||||||||||||||||||
This table header & footer: |
- ^ mMb – 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).
- age of universe.
- ^
Modes of decay:
EC: Electron capture IT: Isomeric transitionn: Neutron emission p: Proton emission - ^ Bold symbol as daughter – Daughter product is stable.
- ^ ( ) spin value – Indicates spin with weak assignment arguments.
- ^ # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
- ^ Believed to decay by β+β+ to 92Zr with a half-life over 1.9×1020 years
- ^ Fission product
- ^ Believed to decay by β−β− to 98Ru with a half-life of over 1×1014 years
- ^ Used to produce the medically useful radioisotope technetium-99m
- ^ Primordial radionuclide
Molybdenum-99
Molybdenum-99 is produced commercially by intense neutron-bombardment of a highly purified uranium-235 target, followed rapidly by extraction.[7] It is used as a parent radioisotope in technetium-99m generators to produce the even shorter-lived daughter isotope technetium-99m, which is used in approximately 40 million medical procedures annually. A common misunderstanding or misnomer is that 99Mo is used in these diagnostic medical scans, when actually it has no role in the imaging agent or the scan itself. In fact, 99Mo co-eluted with the 99mTc (also known as breakthrough) is considered a contaminant and is minimised to adhere to the appropriate USP (or equivalent) regulations and standards. The IAEA recommends that 99Mo concentrations exceeding more than 0.15 µCi/mCi 99mTc or 0.015% should not be administered for usage in humans.[8] Typically, quantification of 99Mo breakthrough is performed for every elution when using a 99Mo/99mTc generator during QA-QC testing of the final product.
There are alternative routes for generating 99Mo that do not require a fissionable target, such as high or low enriched uranium (i.e., HEU or LEU). Some of these include accelerator-based methods, such as proton bombardment or
In the last decade, cooperative agreements between the US government and private capital entities have resurrected neutron capture production for commercially distributed 99Mo/99mTc in the United States of America.[11] The return to neutron-capture-based 99Mo has also been accompanied by the implementation of novel separation methods that allow for low-specific activity 99Mo to be utilized.
References
- .
- ^ PMID 34611245.
- ^ "Standard Atomic Weights: Molybdenum". CIAAW. 2013.
- ISSN 1365-3075.
- ^ ISBN 978-0-8493-0487-3.
- .
- S2CID 122507063.
- ^ Ibrahim I, Zulkifli H, Bohari Y, Zakaria I, Wan Hamirul BWK. Minimizing Molybdenum-99 Contamination In Technetium-99m Pertechnetate From The Elution Of 99Mo/99mTc Generator (PDF) (Report).
- OSTI 5612212.
- OSTI 4589063.
- ^ "Emerging leader with new solutions in the field of nuclear medicine technology". NorthStar Medical Radioisotopes, LLC. Retrieved 2020-01-23.
- Isotopic compositions and standard atomic masses from:
- .
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". .
- "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;
- 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.). ISBN 978-0-8493-0485-9.