Isotopes of molybdenum
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Standard atomic weight Ar°(Mo) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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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
[edit]Nuclide [n 1] |
Z | N | Isotopic mass (Da)[6] [n 2][n 3] |
Half-life [n 4] |
Decay mode [n 5] |
Daughter isotope [n 6] |
Spin and parity [n 7][n 8] |
Natural abundance (mole fraction) | |||||||||||
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Excitation energy | Normal proportion | Range of variation | |||||||||||||||||
81Mo | 42 | 39 | 80.96623(54)# | 1# ms [>400 ns] |
β+? | 81Nb | 5/2+# | ||||||||||||
β+, p? | 80Zr | ||||||||||||||||||
82Mo | 42 | 40 | 81.95666(43)# | 30# ms [>400 ns] |
β+? | 82Nb | 0+ | ||||||||||||
β+, p? | 81Zr | ||||||||||||||||||
83Mo | 42 | 41 | 82.95025(43)# | 23(19) ms | β+ | 83Nb | 3/2−# | ||||||||||||
β+, p? | 82Zr | ||||||||||||||||||
84Mo | 42 | 42 | 83.94185(32)# | 2.3(3) s | β+ | 84Nb | 0+ | ||||||||||||
β+, p? | 83Zr | ||||||||||||||||||
85Mo | 42 | 43 | 84.938261(17) | 3.2(2) s | β+ (99.86%) | 85Nb | (1/2+) | ||||||||||||
β+, p (0.14%) | 84Zr | ||||||||||||||||||
86Mo | 42 | 44 | 85.931174(3) | 19.1(3) s | β+ | 86Nb | 0+ | ||||||||||||
87Mo | 42 | 45 | 86.928196(3) | 14.1(3) 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 | 89Mo | (1/2−) | ||||||||||||||
90Mo | 42 | 48 | 89.913931(4) | 5.56(9) h | β+ | 90Nb | 0+ | ||||||||||||
90mMo | 2874.73(15) keV | 1.14(5) μs | IT | 90Mo | 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 (50.0%) | 91Mo | 1/2− | ||||||||||||||
β+ (50.0%) | 91Nb | ||||||||||||||||||
92Mo | 42 | 50 | 91.90680715(17) | Observationally Stable[n 9] | 0+ | 0.14649(106) | |||||||||||||
92mMo | 2760.52(14) keV | 190(3) ns | IT | 92Mo | 8+ | ||||||||||||||
93Mo | 42 | 51 | 92.90680877(19) | 4839(63) y[2] | EC (95.7%) | 93mNb | 5/2+ | ||||||||||||
EC (4.3%) | 93Nb | ||||||||||||||||||
93m1Mo | 2424.95(4) keV | 6.85(7) h | IT (99.88%) | 93Mo | 21/2+ | ||||||||||||||
β+ (0.12%) | 93Nb | ||||||||||||||||||
93m2Mo | 9695(17) keV | 1.8(10) μs | IT | 93Mo | (39/2−) | ||||||||||||||
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(8) | |||||||||||||
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) | 65.932(5) h | β− | 99mTc | 1/2+ | ||||||||||||
99m1Mo | 97.785(3) keV | 15.5(2) μs | IT | 99Mo | 5/2+ | ||||||||||||||
99m2Mo | 684.10(19) keV | 760(60) ns | IT | 99Mo | 11/2− | ||||||||||||||
100Mo[n 13][n 10] | 42 | 58 | 99.9074680(3) | 7.07(14)×1018 a | β−β− | 100Ru | 0+ | 0.09744(65) | |||||||||||
101Mo | 42 | 59 | 100.9103376(3) | 14.61(3) min | β− | 101Tc | 1/2+ | ||||||||||||
101m1Mo | 13.497(9) keV | 226(7) ns | IT | 101Mo | 3/2+ | ||||||||||||||
101m2Mo | 57.015(11) keV | 133(70) ns | IT | 101Mo | 5/2+ | ||||||||||||||
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 | 104.9169798(23)[7] | 36.3(8) 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).
- ^ Bold half-life – nearly stable, half-life longer than age of universe.
- ^
Modes of decay:
EC: Electron capture 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.
- ^ # – 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 y
- ^ a b c d e 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
[edit]Molybdenum-99 is produced commercially by intense neutron-bombardment of a highly purified uranium-235 target, followed rapidly by extraction.[8] 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.[9] 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 photoneutron reactions on enriched 100Mo targets. Historically, 99Mo generated by neutron capture on natural isotopic molybdenum or enriched 98Mo targets was used for the development of commercial 99Mo/99mTc generators.[10][11] The neutron-capture process was eventually superseded by fission-based 99Mo that could be generated with much higher specific activities. Implementing feed-stocks of high specific activity 99Mo solutions thus allowed for higher quality production and better separations of 99mTc from 99Mo on small alumina column using chromatography. Employing low-specific activity 99Mo under similar conditions is particularly problematic in that either higher Mo loading capacities or larger columns are required for accommodating equivalent amounts of 99Mo. Chemically speaking, this phenomenon occurs due to other Mo isotopes present aside from 99Mo that compete for surface site interactions on the column substrate. In turn, low-specific activity 99Mo usually requires much larger column sizes and longer separation times, and usually yields 99mTc accompanied by unsatisfactory amounts of the parent radioisotope when using γ-alumina as the column substrate. Ultimately, the inferior end-product 99mTc generated under these conditions makes it essentially incompatible with the commercial supply-chain.
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.[12] 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
[edit]- ^ a b 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.
- ^ a b Kajan, I.; Heinitz, S.; Kossert, K.; Sprung, P.; Dressler, R.; Schumann, D. (2021-10-05). "First direct determination of the 93Mo half-life". Scientific Reports. 11 (1). doi:10.1038/s41598-021-99253-5. ISSN 2045-2322. PMC 8492754. PMID 34611245.
- ^ "Standard Atomic Weights: Molybdenum". CIAAW. 2013.
- ^ 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.
- ^ a b Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press. Section 11. ISBN 978-0-8493-0487-3.
- ^ 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.
- ^ Jaries, A.; Stryjczyk, M.; Kankainen, A.; Ayoubi, L. Al; Beliuskina, O.; Canete, L.; de Groote, R. P.; Delafosse, C.; Delahaye, P.; Eronen, T.; Flayol, M.; Ge, Z.; Geldhof, S.; Gins, W.; Hukkanen, M.; Imgram, P.; Kahl, D.; Kostensalo, J.; Kujanpää, S.; Kumar, D.; Moore, I. D.; Mougeot, M.; Nesterenko, D. A.; Nikas, S.; Patel, D.; Penttilä, H.; Pitman-Weymouth, D.; Pohjalainen, I.; Raggio, A.; Ramalho, M.; Reponen, M.; Rinta-Antila, S.; de Roubin, A.; Ruotsalainen, J.; Srivastava, P. C.; Suhonen, J.; Vilen, M.; Virtanen, V.; Zadvornaya, A. "Physical Review C - Accepted Paper: Isomeric states of fission fragments explored via Penning trap mass spectrometry at IGISOL". journals.aps.org. arXiv:2403.04710.
- ^ Frank N. Von Hippel; Laura H. Kahn (December 2006). "Feasibility of Eliminating the Use of Highly Enriched Uranium in the Production of Medical Radioisotopes". Science & Global Security. 14 (2 & 3): 151–162. Bibcode:2006S&GS...14..151V. doi:10.1080/08929880600993071. 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).
- ^ Richards, P. (1989). Technetium-99m: The early days. 3rd International Symposium on Technetium in Chemistry and Nuclear Medicine, Padova, Italy, 5-8 Sep 1989. OSTI 5612212.
- ^ Richards, P. (1965-10-14). The Technetium-99m Generator (Report). doi:10.2172/4589063. 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:
- 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.