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Standard atomic weight Ar°(Mn) | |||||||||||||||||||||||||||||||||||
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Naturally occurring manganese (25Mn) is composed of one stable isotope, 55Mn. 26 radioisotopes have been characterized, with the most stable being 53Mn with a half-life of 3.7 million years, 54Mn with a half-life of 312.3 days, and 52Mn with a half-life of 5.591 days. All of the remaining radioactive isotopes have half-lives that are less than 3 hours and the majority of these have half-lives that are less than a minute. This element also has 3 meta states.
Manganese is part of the iron group of elements, which are thought to be synthesized in large stars shortly before supernova explosions. 53Mn decays to 53 Cr with a half-life of 3.7 million years. Because of its relatively short half-life, 53Mn occurs only in tiny amounts due to the action of cosmic rays on iron in rocks. [4] Manganese isotopic contents are typically combined with chromium isotopic contents and have found application in isotope geology and radiometric dating. Mn−Cr isotopic ratios reinforce the evidence from 26Al and 107 Pd for the early history of the Solar System. Variations in 53Cr/52Cr and Mn/Cr ratios from several meteorites indicate an initial 53Mn/55Mn ratio that suggests Mn−Cr isotopic systematics must result from in-situ decay of 53Mn in differentiated planetary bodies. Hence 53Mn provides additional evidence for nucleosynthetic processes immediately before coalescence of the Solar System.
The isotopes of manganese range in atomic weight from 46 u (46Mn) to 72 u (72Mn). The primary decay mode before the most abundant stable isotope, 55Mn, is electron capture and the primary mode after is beta decay.
Nuclide [n 1] | Z | N | Isotopic mass (Da) [n 2] [n 3] | Half-life | Decay mode [n 4] | Daughter isotope [n 5] | Spin and parity [n 6] [n 7] | Natural abundance (mole fraction) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Excitation energy [n 7] | Normal proportion | Range of variation | |||||||||||||||||
46Mn | 25 | 21 | 45.98672(12)# | 37(3) ms | β+ (78%) | 46Cr | (4+) | ||||||||||||
β+, p (22%) | 45V | ||||||||||||||||||
β+, α (<1%) | 42Ti | ||||||||||||||||||
β+, 2p (<1%) | 44Ti | ||||||||||||||||||
46mMn | 150(100)# keV | 1# ms | β+ | 46Cr | 1-# | ||||||||||||||
47Mn | 25 | 22 | 46.97610(17)# | 100(50) ms | β+ (96.6%) | 47Cr | 5/2−# | ||||||||||||
β+, p (3.4%) | 46V | ||||||||||||||||||
48Mn | 25 | 23 | 47.96852(12) | 158.1(22) ms | β+ (99.71%) | 48Cr | 4+ | ||||||||||||
β+, p (.027%) | 47V | ||||||||||||||||||
β+, α (6×10−4%) | 44Ti | ||||||||||||||||||
49Mn | 25 | 24 | 48.959618(26) | 382(7) ms | β+ | 49Cr | 5/2− | ||||||||||||
50Mn | 25 | 25 | 49.9542382(11) | 283.29(8) ms | β+ | 50Cr | 0+ | ||||||||||||
50mMn | 229(7) keV | 1.75(3) min | β+ | 50Cr | 5+ | ||||||||||||||
51Mn | 25 | 26 | 50.9482108(11) | 46.2(1) min | β+ | 51Cr | 5/2− | ||||||||||||
52Mn | 25 | 27 | 51.9455655(21) | 5.591(3) d | β+ | 52Cr | 6+ | ||||||||||||
52mMn | 377.749(5) keV | 21.1(2) min | β+ (98.25%) | 52Cr | 2+ | ||||||||||||||
IT (1.75%) | 52Mn | ||||||||||||||||||
53Mn | 25 | 28 | 52.9412901(9) | 3.7(4)×106 y | EC | 53Cr | 7/2− | trace | |||||||||||
54Mn | 25 | 29 | 53.9403589(14) | 312.03(3) d | EC 99.99% | 54Cr | 3+ | ||||||||||||
β− (2.9×10−4%) | 54Fe | ||||||||||||||||||
β+ (5.76×10−7%) | 54Cr | ||||||||||||||||||
55Mn | 25 | 30 | 54.9380451(7) | Stable | 5/2− | 1.0000 | |||||||||||||
56Mn | 25 | 31 | 55.9389049(7) | 2.5789(1) h | β− | 56Fe | 3+ | ||||||||||||
57Mn | 25 | 32 | 56.9382854(20) | 85.4(18) s | β− | 57Fe | 5/2− | ||||||||||||
58Mn | 25 | 33 | 57.93998(3) | 3.0(1) s | β− | 58Fe | 1+ | ||||||||||||
58mMn | 71.78(5) keV | 65.2(5) s | β− (>99.9%) | 58Fe | (4)+ | ||||||||||||||
IT (<.1%) | 58Mn | ||||||||||||||||||
59Mn | 25 | 34 | 58.94044(3) | 4.59(5) s | β− | 59Fe | (5/2)− | ||||||||||||
60Mn | 25 | 35 | 59.94291(9) | 51(6) s | β− | 60Fe | 0+ | ||||||||||||
60mMn | 271.90(10) keV | 1.77(2) s | β− (88.5%) | 60Fe | 3+ | ||||||||||||||
IT (11.5%) | 60Mn | ||||||||||||||||||
61Mn | 25 | 36 | 60.94465(24) | 0.67(4) s | β− | 61Fe | (5/2)− | ||||||||||||
62Mn | 25 | 37 | 61.94843(24) | 671(5) ms | β− (>99.9%) | 62Fe | (3+) | ||||||||||||
β−, n (<.1%) | 61Fe | ||||||||||||||||||
62mMn | 0(150)# keV | 92(13) ms | (1+) | ||||||||||||||||
63Mn | 25 | 38 | 62.95024(28) | 275(4) ms | β− | 63Fe | 5/2−# | ||||||||||||
64Mn | 25 | 39 | 63.95425(29) | 88.8(25) ms | β− (>99.9%) | 64Fe | (1+) | ||||||||||||
β−, n (<.1%) | 63Fe | ||||||||||||||||||
64mMn | 135(3) keV | >100 µs | |||||||||||||||||
65Mn | 25 | 40 | 64.95634(58) | 92(1) ms | β− (>99.9%) | 65Fe | 5/2−# | ||||||||||||
β−, n (<.1%) | 64Fe | ||||||||||||||||||
66Mn | 25 | 41 | 65.96108(43)# | 64.4(18) ms | β− (>99.9%) | 66Fe | |||||||||||||
β−, n (<.1%) | 65Fe | ||||||||||||||||||
67Mn | 25 | 42 | 66.96414(54)# | 45(3) ms | β− | 67Fe | 5/2−# | ||||||||||||
68Mn | 25 | 43 | 67.96930(64)# | 28(4) ms | |||||||||||||||
69Mn | 25 | 44 | 68.97284(86)# | 14(4) ms | 5/2−# | ||||||||||||||
70Mn [5] | 25 | 45 | 69.978050(540)# | 19.9(17) ms | β−=? | 70Fe | (4,5) | ||||||||||||
β−, n? [n 8] | 69Fe | ||||||||||||||||||
β−, 2n? [n 8] | 68Fe | ||||||||||||||||||
71Mn [6] | 25 | 46 | 70.982160(540)# | 16# ms (>400 ns) | β−? [n 8] | 71Fe | 5/2-# | ||||||||||||
β−, n? [n 8] | 70Fe | ||||||||||||||||||
β−, 2n? [n 8] | 69Fe | ||||||||||||||||||
72Mn [7] | 25 | 47 | 71.988010(640)# | 12# ms (>620 ns) | β−? [n 8] | 72Fe | |||||||||||||
β−, n? [n 8] | 71Fe | ||||||||||||||||||
β−, 2n? [n 8] | 70Fe | ||||||||||||||||||
73Mn [8] | 25 | 48 | 72.992810(640)# | 12# ms (>410 ns) | β−? [n 8] | 73Fe | 5/2−# | ||||||||||||
This table header & footer: |
EC: | Electron capture |
IT: | Isomeric transition |
n: | Neutron emission |
p: | Proton emission |
Francium (87Fr) has no stable isotopes. A standard atomic weight cannot be given. Its most stable isotope is 223Fr with a half-life of 22 minutes, occurring in trace quantities in nature as an intermediate decay product of 235U.
Thallium (81Tl) has 41 isotopes with atomic masses that range from 176 to 216. 203Tl and 205Tl are the only stable isotopes and 204Tl is the most stable radioisotope with a half-life of 3.78 years. 207Tl, with a half-life of 4.77 minutes, has the longest half-life of naturally occurring Tl radioisotopes. All isotopes of thallium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
Naturally occurring platinum (78Pt) consists of five stable isotopes (192Pt, 194Pt, 195Pt, 196Pt, 198Pt) and one very long-lived (half-life 6.50×1011 years) radioisotope (190Pt). There are also 34 known synthetic radioisotopes, the longest-lived of which is 193Pt with a half-life of 50 years. All other isotopes have half-lives under a year, most under a day. All isotopes of platinum are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. Platinum-195 is the most abundant isotope.
Naturally occurring gadolinium (64Gd) is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and 1 radioisotope, 152Gd, with 158Gd being the most abundant (24.84% natural abundance). The predicted double beta decay of 160Gd has never been observed; only a lower limit on its half-life of more than 1.3×1021 years has been set experimentally.
Promethium (61Pm) is an artificial element, except in trace quantities as a product of spontaneous fission of 238U and 235U and alpha decay of 151Eu, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. It was first synthesized in 1945.
Naturally occurring lanthanum (57La) is composed of one stable (139La) and one radioactive (138La) isotope, with the stable isotope, 139La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being 138La, with a half-life of 1.02×1011 years; 137La, with a half-life of 60,000 years and 140La, with a half-life of 1.6781 days. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these have half-lives that are less than 1 minute. This element also has 12 nuclear isomers, the longest-lived of which is 132mLa, with a half-life of 24.3 minutes.
Naturally occurring barium (56Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001. This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×1021 years (about 1011 times the age of the universe).
There are 39 known isotopes and 17 nuclear isomers of tellurium (52Te), with atomic masses that range from 104 to 142. These are listed in the table below.
Naturally occurring ruthenium (44Ru) is composed of seven stable isotopes. Additionally, 27 radioactive isotopes have been discovered. Of these radioisotopes, the most stable are 106Ru, with a half-life of 373.59 days; 103Ru, with a half-life of 39.26 days and 97Ru, with a half-life of 2.9 days.
Natural yttrium (39Y) is composed of a single isotope yttrium-89. The most stable radioisotopes are 88Y, which has a half-life of 106.6 days and 91Y with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except 87Y, which has a half-life of 79.8 hours, and 90Y, with 64 hours. The dominant decay mode below the stable 89Y is electron capture and the dominant mode after it is beta emission. Thirty-five unstable isotopes have been characterized.
The alkaline earth metal strontium (38Sr) has four stable, naturally occurring isotopes: 84Sr (0.56%), 86Sr (9.86%), 87Sr (7.0%) and 88Sr (82.58%). Its standard atomic weight is 87.62(1).
Bromine (35Br) has two stable isotopes, 79Br and 81Br, and 32 known radioisotopes, the most stable of which is 77Br, with a half-life of 57.036 hours.
Arsenic (33As) has 33 known isotopes and at least 10 isomers. Only one of these isotopes, 75As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is 73As with a half-life of 80 days. Arsenic has been proposed as a "salting" material for nuclear weapons. A jacket of 75As, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope 76As with a half-life of 1.0778 days and produce approximately 1.13 MeV gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several hours. Such a weapon is not known to have ever been built, tested, or used.
Germanium (32Ge) has five naturally occurring isotopes, 70Ge, 72Ge, 73Ge, 74Ge, and 76Ge. Of these, 76Ge is very slightly radioactive, decaying by double beta decay with a half-life of 1.78 × 1021 years (130 billion times the age of the universe).
Naturally occurring zinc (30Zn) is composed of the 5 stable isotopes 64Zn, 66Zn, 67Zn, 68Zn, and 70Zn with 64Zn being the most abundant. Twenty-five radioisotopes have been characterised with the most abundant and stable being 65Zn with a half-life of 244.26 days, and 72Zn with a half-life of 46.5 hours. All of the remaining radioactive isotopes have half-lives that are less than 14 hours and the majority of these have half-lives that are less than 1 second. This element also has 10 meta states.
Copper (29Cu) has two stable isotopes, 63Cu and 65Cu, along with 27 radioisotopes. The most stable radioisotope is 67Cu with a half-life of 61.83 hours, while the least stable is 54Cu with a half-life of approximately 75 ns. Most have half-lives under a minute. Unstable copper isotopes with atomic masses below 63 tend to undergo β+ decay, while isotopes with atomic masses above 65 tend to undergo β− decay. 64Cu decays by both β+ and β−.
Naturally occurring chromium (24Cr) is composed of four stable isotopes; 50Cr, 52Cr, 53Cr, and 54Cr with 52Cr being the most abundant (83.789% natural abundance). 50Cr is suspected of decaying by β+β+ to 50Ti with a half-life of (more than) 1.8×1017 years. Twenty-two radioisotopes, all of which are entirely synthetic, have been characterized, the most stable being 51Cr with a half-life of 27.7 days. All of the remaining radioactive isotopes have half-lives that are less than 24 hours and the majority of these have half-lives that are less than 1 minute. This element also has two meta states, 45mCr, the more stable one, and 59mCr, the least stable isotope or isomer.
Naturally occurring vanadium (23V) is composed of one stable isotope 51V and one radioactive isotope 50V with a half-life of 2.71×1017 years. 24 artificial radioisotopes have been characterized (in the range of mass number between 40 and 65) with the most stable being 49V with a half-life of 330 days, and 48V with a half-life of 15.9735 days. All of the remaining radioactive isotopes have half-lives shorter than an hour, the majority of them below 10 seconds, the least stable being 42V with a half-life shorter than 55 nanoseconds, with all of the isotopes lighter than it, and none of the heavier, have unknown half-lives. In 4 isotopes, metastable excited states were found (including 2 metastable states for 60V), which adds up to 5 meta states.
Naturally occurring scandium (21Sc) is composed of one stable isotope, 45Sc. Twenty-five radioisotopes have been characterized, with the most stable being 46Sc with a half-life of 83.8 days, 47Sc with a half-life of 3.35 days, and 48Sc with a half-life of 43.7 hours and 44Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound 39Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being 44m2Sc.
Berkelium (97Bk) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are 20 known radioisotopes, from 230Bk and 233Bk to 253Bk, and 6 nuclear isomers. The longest-lived isotope is 247Bk with a half-life of 1,380 years.