Molybdenum Molybdenum is a chemical element; it has Symbol (chemistry), symbol Mo (from Neo-Latin ''molybdaenum'') and atomic number 42. The name derived from Ancient Greek ', meaning lead, since its ores were confused with lead ores. Molybdenum minerals hav ...

(₄₂Mo) has 39 known

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

s, ranging in

atomic mass Atomic mass ( or ) is the mass of a single atom. The atomic mass mostly comes from the combined mass of the protons and neutrons in the nucleus, with minor contributions from the electrons and nuclear binding energy. The atomic mass of atoms, ...

from 81 to 119, as well as four metastable

nuclear isomer A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy excited state levels (higher energy levels). "Metastable" describes nuclei whose excited states have Half-life, half-lives of ...

s. 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 Zirconium is a chemical element; it has Symbol (chemistry), symbol Zr and atomic number 40. First identified in 1789, isolated in impure form in 1824, and manufactured at scale by 1925, pure zirconium is a lustrous transition metal with a greyis ...

niobium Niobium is a chemical element; it has chemical symbol, symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility, ductile transition metal. Pure niobium has a Mohs scale of mineral hardness, Mohs h ...

technetium Technetium is a chemical element; it has Symbol (chemistry), symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive. Technetium and promethium are the only radioactive elements whose neighbours in the sense ...

, and

ruthenium Ruthenium is a chemical element; it has symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is unreactive to most chem ...

. Molybdenum-100, with a

half-life Half-life is a mathematical and scientific description of exponential or gradual decay. Half-life, half life or halflife may also refer to: Film * Half-Life (film), ''Half-Life'' (film), a 2008 independent film by Jennifer Phang * ''Half Life: ...

of 7.07 years, is the only naturally occurring radioisotope. It undergoes

double beta decay In nuclear physics, double beta decay is a type of radioactive decay in which two neutrons are simultaneously transformed into two protons, or vice versa, inside an atomic nucleus. As in single beta decay, this process allows the atom to move cl ...

into

-100. Molybdenum-98 is the most common isotope, comprising 24.14% of all molybdenum on Earth.

List of isotopes

, -id=Molybdenum-81 , rowspan=2, ⁸¹Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 39 , rowspan=2, 80.96623(54)# , rowspan=2, 1# ms
400 ns, β⁺? , ⁸¹Nb , rowspan=2, 5/2+# , rowspan=2, , rowspan=2, , - , β⁺, p? , ⁸⁰Zr , -id=Molybdenum-82 , rowspan=2, ⁸²Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 40 , rowspan=2, 81.95666(43)# , rowspan=2, 30# ms
400 ns, β⁺? , ⁸²Nb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p? , ⁸¹Zr , -id=Molybdenum-83 , rowspan=2, ⁸³Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 41 , rowspan=2, 82.95025(43)# , rowspan=2, 23(19) ms , β⁺ , ⁸³Nb , rowspan=2, 3/2−# , rowspan=2, , rowspan=2, , - , β⁺, p? , ⁸²Zr , -id=Molybdenum-84 , rowspan=2, ⁸⁴Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 42 , rowspan=2, 83.94185(32)# , rowspan=2, 2.3(3) s , β⁺ , ⁸⁴Nb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p? , ⁸³Zr , -id=Molybdenum-85 , rowspan=2, ⁸⁵Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 43 , rowspan=2, 84.938261(17) , rowspan=2, 3.2(2) s , β⁺ (99.86%) , ⁸⁵Nb , rowspan=2, (1/2+) , rowspan=2, , rowspan=2, , - , β⁺, p (0.14%) , ⁸⁴Zr , -id=Molybdenum-86 , ⁸⁶Mo , style="text-align:right" , 42 , style="text-align:right" , 44 , 85.931174(3) , 19.1(3) s , β⁺ , ⁸⁶Nb , 0+ , , , -id=Molybdenum-87 , rowspan=2, ⁸⁷Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 45 , rowspan=2, 86.928196(3) , rowspan=2, 14.1(3) s , β⁺ (85%) , ⁸⁷Nb , rowspan=2, 7/2+# , rowspan=2, , rowspan=2, , - , β⁺, p (15%) , ⁸⁶Zr , -id=Molybdenum-88 , ⁸⁸Mo , style="text-align:right" , 42 , style="text-align:right" , 46 , 87.921968(4) , 8.0(2) min , β⁺ , ⁸⁸Nb , 0+ , , , -id=Molybdenum-89 , ⁸⁹Mo , style="text-align:right" , 42 , style="text-align:right" , 47 , 88.919468(4) , 2.11(10) min , β⁺ , ⁸⁹Nb , (9/2+) , , , -id=Molybdenum-89m , style="text-indent:1em" , ^89mMo , colspan="3" style="text-indent:2em" , 387.5(2) keV , 190(15) ms , IT , ⁸⁹Mo , (1/2−) , , , -id=Molybdenum-90 , ⁹⁰Mo , style="text-align:right" , 42 , style="text-align:right" , 48 , 89.913931(4) , 5.56(9) h , β⁺ , ⁹⁰Nb , 0+ , , , -id=Molybdenum-90m , style="text-indent:1em" , ^90mMo , colspan="3" style="text-indent:2em" , 2874.73(15) keV , 1.14(5) μs , IT , ⁹⁰Mo , 8+ , , , -id=Molybdenum-91 , ⁹¹Mo , style="text-align:right" , 42 , style="text-align:right" , 49 , 90.911745(7) , 15.49(1) min , β⁺ , ⁹¹Nb , 9/2+ , , , -id=Molybdenum-91m , rowspan=2 style="text-indent:1em" , ^91mMo , rowspan=2 colspan="3" style="text-indent:2em" , 653.01(9) keV , rowspan=2, 64.6(6) s , IT (50.0%) , ⁹¹Mo , rowspan=2, 1/2− , rowspan=2, , rowspan=2, , - , β⁺ (50.0%) , ⁹¹Nb , -id=Molybdenum-92 , ⁹²Mo , style="text-align:right" , 42 , style="text-align:right" , 50 , 91.90680715(17) , colspan=3 align=center,

Observationally Stable Stable nuclides are isotopes of a chemical element whose nucleons are in a configuration that does not permit them the surplus energy required to produce a radioactive emission. The nuclei of such isotopes are not radioactive and unlike radionuc ...

Believed to decay by β⁺β⁺ to ⁹²Zr with a half-life over 1.9×10²⁰ y , 0+ , 0.14649(106) , , -id=Molybdenum-92m , style="text-indent:1em" , ^92mMo , colspan="3" style="text-indent:2em" , 2760.52(14) keV , 190(3) ns , IT , ⁹²Mo , 8+ , , , -id=Molybdenum-93 , rowspan=2, ⁹³Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 51 , rowspan=2, 92.90680877(19) , rowspan=2, 4839(63) y , EC (95.7%) , ^93mNb , rowspan=2, 5/2+ , rowspan=2, , rowspan=2, , - , EC (4.3%) , ⁹³Nb , -id=Molybdenum-93m1 , rowspan=2 style="text-indent:1em" , ^93m1Mo , rowspan=2 colspan="3" style="text-indent:2em" , 2424.95(4) keV , rowspan=2, 6.85(7) h , IT (99.88%) , ⁹³Mo , rowspan=2, 21/2+ , rowspan=2, , rowspan=2, , - , β⁺ (0.12%) , ⁹³Nb , -id=Molybdenum-93m2 , style="text-indent:1em" , ^93m2Mo , colspan="3" style="text-indent:2em" , 9695(17) keV , 1.8(10) μs , IT , ⁹³Mo , (39/2−) , , , -id=Molybdenum-94 , ⁹⁴Mo , style="text-align:right" , 42 , style="text-align:right" , 52 , 93.90508359(15) , colspan=3 align=center, Stable , 0+ , 0.09187(33) , , -id=Molybdenum-95 , ⁹⁵Mo Fission product , style="text-align:right" , 42 , style="text-align:right" , 53 , 94.90583744(13) , colspan=3 align=center, Stable , 5/2+ , 0.15873(30) , , -id=Molybdenum-96 , ⁹⁶Mo , style="text-align:right" , 42 , style="text-align:right" , 54 , 95.90467477(13) , colspan=3 align=center, Stable , 0+ , 0.16673(8) , , -id=Molybdenum-97 , ⁹⁷Mo , style="text-align:right" , 42 , style="text-align:right" , 55 , 96.90601690(18) , colspan=3 align=center, Stable , 5/2+ , 0.09582(15) , , -id=Molybdenum-98 , ⁹⁸Mo , style="text-align:right" , 42 , style="text-align:right" , 56 , 97.90540361(19) , colspan=3 align=center, Observationally StableBelieved to decay by β⁻β⁻ to ⁹⁸Ru with a half-life of over 1×10¹⁴ years , 0+ , 0.24292(80) , , - , ⁹⁹MoUsed to produce the medically useful radioisotope

technetium-99m Technetium-99m (99mTc) is a metastable nuclear isomer of technetium-99 (itself an isotope of technetium), symbolized as 99mTc, that is used in tens of millions of medical diagnostic procedures annually, making it the most commonly used Radiophar ...

, style="text-align:right" , 42 , style="text-align:right" , 57 , 98.90770730(25) , 65.932(5) h , β⁻ , ^99mTc , 1/2+ , , , -id=Molybdenum-99m1 , style="text-indent:1em" , ^99m1Mo , colspan="3" style="text-indent:2em" , 97.785(3) keV , 15.5(2) μs , IT , ⁹⁹Mo , 5/2+ , , , -id=Molybdenum-99m2 , style="text-indent:1em" , ^99m2Mo , colspan="3" style="text-indent:2em" , 684.10(19) keV , 760(60) ns , IT , ⁹⁹Mo , 11/2− , , , -id=Molybdenum-100 , ¹⁰⁰Mo Primordial

radionuclide A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ...

, style="text-align:right" , 42 , style="text-align:right" , 58 , 99.9074680(3) , 7.07(14)×10¹⁸ y , β⁻β⁻ , ¹⁰⁰Ru , 0+ , 0.09744(65) , , -id=Molybdenum-101 , ¹⁰¹Mo , style="text-align:right" , 42 , style="text-align:right" , 59 , 100.9103376(3) , 14.61(3) min , β⁻ , ¹⁰¹Tc , 1/2+ , , , -id=Molybdenum-101m1 , style="text-indent:1em" , ^101m1Mo , colspan="3" style="text-indent:2em" , 13.497(9) keV , 226(7) ns , IT , ¹⁰¹Mo , 3/2+ , , , -id=Molybdenum-101m2 , style="text-indent:1em" , ^101m2Mo , colspan="3" style="text-indent:2em" , 57.015(11) keV , 133(70) ns , IT , ¹⁰¹Mo , 5/2+ , , , -id=Molybdenum-102 , ¹⁰²Mo , style="text-align:right" , 42 , style="text-align:right" , 60 , 101.910294(9) , 11.3(2) min , β⁻ , ¹⁰²Tc , 0+ , , , -id=Molybdenum-103 , ¹⁰³Mo , style="text-align:right" , 42 , style="text-align:right" , 61 , 102.913092(10) , 67.5(15) s , β⁻ , ¹⁰³Tc , 3/2+ , , , -id=Molybdenum-104 , ¹⁰⁴Mo , style="text-align:right" , 42 , style="text-align:right" , 62 , 103.913747(10) , 60(2) s , β⁻ , ¹⁰⁴Tc , 0+ , , , -id=Molybdenum-105 , ¹⁰⁵Mo , style="text-align:right" , 42 , style="text-align:right" , 63 , 104.9169798(23) , 36.3(8) s , β⁻ , ¹⁰⁵Tc , (5/2−) , , , -id=Molybdenum-106 , ¹⁰⁶Mo , style="text-align:right" , 42 , style="text-align:right" , 64 , 105.9182732(98) , 8.73(12) s , β⁻ , ¹⁰⁶Tc , 0+ , , , -id=Molybdenum-107 , ¹⁰⁷Mo , style="text-align:right" , 42 , style="text-align:right" , 65 , 106.9221198(99) , 3.5(5) s , β⁻ , ¹⁰⁷Tc , (1/2+) , , , -id=Molybdenum-107m , style="text-indent:1em" , ^107mMo , colspan="3" style="text-indent:2em" , 65.4(2) keV , 445(21) ns , IT , ¹⁰⁷Mo , (5/2+) , , , -id=Molybdenum-108 , rowspan=2, ¹⁰⁸Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 66 , rowspan=2, 107.9240475(99) , rowspan=2, 1.105(10) s , β⁻ (>99.5%) , ¹⁰⁸Tc , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n (<0.5%) , ¹⁰⁷Tc , -id=Molybdenum-109 , rowspan=2, ¹⁰⁹Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 67 , rowspan=2, 108.928438(12) , rowspan=2, 700(14) ms , β⁻ (98.7%) , ¹⁰⁹Tc , rowspan=2, (1/2+) , rowspan=2, , rowspan=2, , - , β⁻, n (1.3%) , ¹⁰⁸Tc , -id=Molybdenum-109m , style="text-indent:1em" , ^109mMo , colspan="3" style="text-indent:2em" , 69.7(5) keV , 210(60) ns , IT , ¹⁰⁹Mo , 5/2+# , , , -id=Molybdenum-110 , rowspan=2, ¹¹⁰Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 68 , rowspan=2, 109.930718(26) , rowspan=2, 292(7) ms , β⁻ (98.0%) , ¹¹⁰Tc , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n (2.0%) , ¹⁰⁹Tc , -id=Molybdenum-111 , rowspan=2, ¹¹¹Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 69 , rowspan=2, 110.935652(14) , rowspan=2, 193.6(44) ms , β⁻ (>88%) , ¹¹¹Tc , rowspan=2, 1/2+# , rowspan=2, , rowspan=2, , - , β⁻, n (<12%) , ¹¹⁰Tc , -id=Molybdenum-111m , rowspan=2 style="text-indent:1em" , ^111mMo , rowspan=2 colspan="3" style="text-indent:2em" , 100(50)# keV , rowspan=2, ~200 ms , β⁻ , ¹¹¹Tc , rowspan=2, 7/2−# , rowspan=2, , rowspan=2, , - , β⁻, n? , ¹¹⁰Tc , -id=Molybdenum-112 , rowspan=2, ¹¹²Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 70 , rowspan=2, 111.93829(22)# , rowspan=2, 125(5) ms , β⁻ , ¹¹²Tc , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n? , ¹¹¹Tc , -id=Molybdenum-113 , rowspan=2, ¹¹³Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 71 , rowspan=2, 112.94348(32)# , rowspan=2, 80(2) ms , β⁻ , ¹¹³Tc , rowspan=2, 5/2+# , rowspan=2, , rowspan=2, , - , β⁻, n? , ¹¹²Tc , -id=Molybdenum-114 , rowspan=2, ¹¹⁴Mo , rowspan=2 style="text-align:right" , 42 , rowspan=2 style="text-align:right" , 72 , rowspan=2, 113.94667(32)# , rowspan=2, 58(2) ms , β⁻ , ¹¹⁴Tc , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n? , ¹¹³Tc , -id=Molybdenum-115 , rowspan=3, ¹¹⁵Mo , rowspan=3 style="text-align:right" , 42 , rowspan=3 style="text-align:right" , 73 , rowspan=3, 114.95217(43)# , rowspan=3, 45.5(20) ms , β⁻ , ¹¹⁵Tc , rowspan=3, 3/2+# , rowspan=3, , rowspan=3, , - , β⁻, n? , ¹¹⁴Tc , - , β⁻, 2n? , ¹¹³Tc , -id=Molybdenum-116 , rowspan=3, ¹¹⁶Mo , rowspan=3 style="text-align:right" , 42 , rowspan=3 style="text-align:right" , 74 , rowspan=3, 115.95576(54)# , rowspan=3, 32(4) ms , β⁻ , ¹¹⁶Tc , rowspan=3, 0+ , rowspan=3, , rowspan=3, , - , β⁻, n? , ¹¹⁵Tc , - , β⁻, 2n? , ¹¹⁴Tc , -id=Molybdenum-117 , rowspan=3, ¹¹⁷Mo , rowspan=3 style="text-align:right" , 42 , rowspan=3 style="text-align:right" , 75 , rowspan=3, 116.96169(54)# , rowspan=3, 22(5) ms , β⁻ , ¹¹⁷Tc , rowspan=3, 3/2+# , rowspan=3, , rowspan=3, , - , β⁻, n? , ¹¹⁶Tc , - , β⁻, 2n? , ¹¹⁵Tc , -id=Molybdenum-118 , rowspan=3, ¹¹⁸Mo , rowspan=3 style="text-align:right" , 42 , rowspan=3 style="text-align:right" , 76 , rowspan=3, 117.96525(54)# , rowspan=3, 21(6) ms , β⁻ , ¹¹⁸Tc , rowspan=3, 0+ , rowspan=3, , rowspan=3, , - , β⁻, n? , ¹¹⁷Tc , - , β⁻, 2n? , ¹¹⁶Tc , -id=Molybdenum-119 , rowspan=3, ¹¹⁹Mo , rowspan=3 style="text-align:right" , 42 , rowspan=3 style="text-align:right" , 77 , rowspan=3, 118.97147(32)# , rowspan=3, 12# ms
550 ns, β⁻? , ¹¹⁹Tc , rowspan=3, 3/2+# , rowspan=3, , rowspan=3, , - , β⁻, n? , ¹¹⁸Tc , - , β⁻, 2n? , ¹¹⁷Tc

Molybdenum-99

Molybdenum-99 is produced commercially by intense neutron-bombardment of a highly purified

uranium-235 Uranium-235 ( or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nat ...

target, followed rapidly by extraction. It is used as a parent radioisotope in

technetium-99m generator A technetium-99m generator, or colloquially a technetium cow or moly cow, is a device used to extract the metastable isotope 99mTc of technetium from a decaying sample of molybdenum-99. 99Mo has a half-life of 66 hours and can be easily tran ...

s to produce the even shorter-lived daughter isotope

, 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. 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. 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 In chemical analysis, chromatography is a laboratory technique for the Separation process, separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it ...

. 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. 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

* Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Navbox element isotopes Molybdenum

List of isotopes

Molybdenum-99

See also

References