Naturally occurring
manganeseManganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...
(
Mn) is composed of 1 stable
isotopeIsotopes are different types of atoms of the same chemical element, each having a different number of neutrons. Correspondingly, isotopes differ in mass number but not in atomic number. The difference in the number of nucleons comes from a difference how many neutrons are in the atomic nucleus...
;
55Mn. 18 radioisotopes have been characterized with the most stable being
53Mn with a
half-lifeHalf-life is the period of time, for a substance undergoing decay, to decrease by half. The name originally was used to describe a characteristic of unstable atoms , but may apply to any quantity which follows a set-rate decay....
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 1 minute. This element also has 3 meta states.
Manganese is part of the
ironIron is a metallic chemical element with the symbol Fe and atomic number 26. Iron is a group 8 and period 4 element and is therefore classified as a transition metal. Iron and iron alloys are by far the most common metals and the most common ferromagnetic materials in everyday use...
group of elements which are thought to be synthesized in large
starA star is a massive, luminous ball of plasma that is held together by gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun...
s shortly before
supernovaA supernova is a stellar explosion. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months. During this short interval, a supernova can radiate as much energy as the Sun could emit over...
explosion.
53Mn decays to
53CrChromium is a chemical element which has the symbol Cr and atomic number 24, first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odourless, tasteless, and malleable...
with a
half-lifeHalf-life is the period of time, for a substance undergoing decay, to decrease by half. The name originally was used to describe a characteristic of unstable atoms , but may apply to any quantity which follows a set-rate decay....
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
ironIron is a metallic chemical element with the symbol Fe and atomic number 26. Iron is a group 8 and period 4 element and is therefore classified as a transition metal. Iron and iron alloys are by far the most common metals and the most common ferromagnetic materials in everyday use...
in rocks . Manganese isotopic contents are typically combined with
chromiumChromium is a chemical element which has the symbol Cr and atomic number 24, first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odourless, tasteless, and malleable...
isotopic contents and have found application in isotope geology and
radiometric datingRadiometric dating is a technique used to date materials, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates...
. Mn-Cr isotopic ratios reinforce the evidence from
26AlAluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13. It is not soluble in water under normal circumstances....
and
107PdPalladium is a chemical element with the chemical symbol Pd and an atomic number of 46. Palladium is a rare and lustrous silvery-white metal that was discovered in 1803 by William Hyde Wollaston, who named it after the asteroid Pallas, which in turn, was named after the epithet of the Greek...
for the early history of the
solar systemThe Solar System consists of the Sun and those celestial objects bound to it by gravity, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago...
. Variations in
53Cr/
52Cr and Mn/Cr ratios from several
meteoriteA meteorite is a natural object originating in outer space that survives an impact with the Earth's surface. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...
s 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
nucleosyntheticNucleosynthesis is the process of creating new atomic nuclei from preexisting nucleons . It is thought that the primordial nucleons themselves were formed from the quark-gluon plasma from the Big Bang as it cooled below two trillion degrees...
processes immediately before coalescence of the
solar systemThe Solar System consists of the Sun and those celestial objects bound to it by gravity, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago...
.
The isotopes of manganese range in
atomic weightAtomic weight is a dimensionless physical quantity, the ratio of the average mass of atoms of an element to 1/12 of the mass of an atom of carbon-12...
from 46
uThe unified atomic mass unit or atomic mass unit , or dalton or, sometimes, universal mass unit , is a unit of mass used to express atomic and molecular masses...
(
46Mn) to 65 u (
65Mn). The primary decay mode before the most abundant stable isotope,
55Mn, is
electron captureElectron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom and insufficient energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron emission...
and the primary mode after is
beta decayIn nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted. In the case of electron emission, it is referred to as beta minus , while in the case of a positron emission as beta plus...
.
Standard atomic mass: 54.938045(5) u
Table
nuclide
symbol |
Z(pThe proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H +...
) |
N(nThe neutron is a subatomic particle with no net electric charge and a mass slightly larger than that of a proton.Neutron are usually found in atomic nuclei. The nuclei of most atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of protons in a...
) |
isotopic mass (u)
|
half-life |
nuclear
spin |
representative
isotopic
composition
(mole fraction) |
range of natural
variation
(mole fraction) |
| excitation energy |
| 44Mn |
25 |
19 |
44.00687(54)# |
<105 ns |
(2-)# |
|
|
| 45Mn |
25 |
20 |
44.99451(32)# |
<70 ns |
(7/2-)# |
|
|
| 46Mn |
25 |
21 |
45.98672(12)# |
37(3) ms |
(4+) |
|
|
| 46mMn |
150(100)# keV |
1# ms |
1-# |
|
|
| 47Mn |
25 |
22 |
46.97610(17)# |
100(50) ms |
5/2-# |
|
|
| 48Mn |
25 |
23 |
47.96852(12) |
158.1(22) ms |
4+ |
|
|
| 49Mn |
25 |
24 |
48.959618(26) |
382(7) ms |
5/2- |
|
|
| 50Mn |
25 |
25 |
49.9542382(11) |
283.29(8) ms |
0+ |
|
|
| 50mMn |
229(7) keV |
1.75(3) min |
5+ |
|
|
| 51Mn |
25 |
26 |
50.9482108(11) |
46.2(1) min |
5/2- |
|
|
| 52Mn |
25 |
27 |
51.9455655(21) |
5.591(3) d |
6+ |
|
|
| 52mMn |
377.749(5) keV |
21.1(2) min |
2+ |
|
|
| 53Mn |
25 |
28 |
52.9412901(9) |
3.74(4)E+6 a |
7/2- |
|
|
| 54Mn |
25 |
29 |
53.9403589(14) |
312.03(3) d |
3+ |
|
|
| 55Mn |
25 |
30 |
54.9380451(7) |
STABLE |
5/2- |
1.0000 |
|
| 56Mn |
25 |
31 |
55.9389049(7) |
2.5789(1) h |
3+ |
|
|
| 57Mn |
25 |
32 |
56.9382854(20) |
85.4(18) s |
5/2- |
|
|
| 58Mn |
25 |
33 |
57.93998(3) |
3.0(1) s |
1+ |
|
|
| 58mMn |
71.78(5) keV |
65.2(5) s |
(4)+ |
|
|
| 59Mn |
25 |
34 |
58.94044(3) |
4.59(5) s |
(5/2)- |
|
|
| 60Mn |
25 |
35 |
59.94291(9) |
51(6) s |
0+ |
|
|
| 60mMn |
271.90(10) keV |
1.77(2) s |
3+ |
|
|
| 61Mn |
25 |
36 |
60.94465(24) |
0.67(4) s |
(5/2)- |
|
|
| 62Mn |
25 |
37 |
61.94843(24) |
671(5) ms |
(3+) |
|
|
| 62mMn |
0(150)# keV |
92(13) ms |
(1+) |
|
|
| 63Mn |
25 |
38 |
62.95024(28) |
275(4) ms |
5/2-# |
|
|
| 64Mn |
25 |
39 |
63.95425(29) |
88.8(25) ms |
(1+) |
|
|
| 64mMn |
135(3) keV |
>100 µs |
|
|
|
| 65Mn |
25 |
40 |
64.95634(58) |
92(1) ms |
5/2-# |
|
|
| 66Mn |
25 |
41 |
65.96108(43)# |
64.4(18) ms |
|
|
|
| 67Mn |
25 |
42 |
66.96414(54)# |
45(3) ms |
5/2-# |
|
|
| 68Mn |
25 |
43 |
67.96930(64)# |
28(4) ms |
|
|
|
| 69Mn |
25 |
44 |
68.97284(86)# |
14(4) ms |
5/2-# |
|
|