Manganese is a
chemical element
A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...
with the
symbol
A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different conc ...
Mn and
atomic number
The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei, this is equal to the proton number (''n''p) or the number of protons found in the nucleus of every ...
25. It is a hard, brittle, silvery metal, often found in
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...
s in combination with
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
. Manganese is a
transition metal
In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. They are the elements that can ...
with a multifaceted array of industrial
alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...
uses, particularly in
stainless steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
s. It improves strength, workability, and resistance to wear. Manganese oxide is used as an oxidising agent; as a rubber additive; and in glass making, fertilisers, and ceramics. Manganese sulfate can be used as a fungicide.
Manganese is also an essential human dietary element, important in macronutrient metabolism, bone formation, and
free radical
A daughter category of ''Ageing'', this category deals only with the biological aspects of ageing.
Ageing
Ailments of unknown cause
Biogerontology
Biological processes
Causes of death
Cellular processes
Gerontology
Life extension
Metabo ...
defense systems. It is a critical component in dozens of proteins and enzymes.
It is found mostly in the bones, but also the liver, kidneys, and brain.
In the human brain, the manganese is bound to manganese
metalloprotein
Metalloprotein is a generic term for a protein that contains a metal ion Cofactor (biochemistry), cofactor. A large proportion of all proteins are part of this category. For instance, at least 1000 human proteins (out of ~20,000) contain zinc-bi ...
s, most notably
glutamine synthetase
Glutamine synthetase (GS) () is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine:
Glutamate + Adenosine triphosphate, ATP + NH3 → Glutamine + Ad ...
in
astrocyte
Astrocytes (from Ancient Greek , , "star" + , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of endo ...
s.
Manganese was first isolated in 1774. It is familiar in the laboratory in the form of the deep violet salt
potassium permanganate
Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline salt, that dissolves in water as K+ and , an intensely pink to purple solution.
Potassium permanganate is widely used in the c ...
. It occurs at the
active site
In biology and biochemistry, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of amino acid residues that form temporary bonds with the substrate (binding site) a ...
s in some
enzymes
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
. Of particular interest is the use of a Mn-O
cluster
may refer to:
Science and technology Astronomy
* Cluster (spacecraft), constellation of four European Space Agency spacecraft
* Asteroid cluster, a small asteroid family
* Cluster II (spacecraft), a European Space Agency mission to study t ...
, the
oxygen-evolving complex
The oxygen-evolving complex (OEC), also known as the water-splitting complex, is the portion of photosystem II where photo-oxidation of water occurs during the light reactions of photosynthesis. The OEC is surrounded by four core protein subuni ...
, in the production of oxygen by plants.
Characteristics
Physical properties
Manganese is a silvery-gray
metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
that resembles iron. It is hard and very brittle, difficult to fuse, but easy to oxidize.
Manganese metal and its common ions are
paramagnetic
Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, d ...
.
Manganese tarnishes slowly in air and oxidizes ("rusts") like iron in water containing dissolved oxygen.
Isotopes
Naturally occurring manganese is composed of one stable
isotope
Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) ...
,
55Mn. Several
radioisotope
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...
s have been isolated and described, ranging in
atomic weight
Relative atomic mass (symbol: ''A''; sometimes abbreviated RAM or r.a.m.), also known by the deprecated synonym atomic weight, is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a giv ...
from 44
u (
44Mn) to 69 u (
69Mn). The most stable are
53Mn with a
half-life
Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ato ...
of 3.7 million years,
54Mn with a half-life of 312.2 days, and
52Mn with a half-life of 5.591 days. All of the remaining
radioactive
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consid ...
isotopes have half-lives of less than three hours, and the majority of less than one minute. The primary
decay mode
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consid ...
in isotopes lighter than the most abundant stable isotope,
55Mn, is
electron capture
Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. Thi ...
and the primary mode in heavier isotopes is
beta decay
In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...
.
Manganese also has three
meta state
A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy higher energy levels than in the ground state of the same nucleus. "Metastable" describes nuclei whose excited states have ha ...
s.
Manganese is part of the
iron group
In chemistry and physics, the iron group refers to elements that are in some way related to iron; mostly in period (row) 4 of the periodic table. The term has different meanings in different contexts.
In chemistry, the term is largely obsolete, ...
of elements, which are thought to be synthesized in large
star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
s shortly before the
supernova
A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...
explosion.
53Mn decays to
53Cr with a half-life of 3.7 million years. Because of its relatively short half-life,
53Mn is relatively rare, produced by
cosmic rays
Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...
impact on
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
. Manganese isotopic contents are typically combined with
chromium
Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal.
Chromium metal is valued for its high corrosion resistance and hardne ...
isotopic contents and have found application in
isotope geology
Isotope geochemistry is an aspect of geology based upon the study of natural variations in the relative abundances of isotopes of various Chemical element, elements. Variations in isotopic abundance are measured by isotope ratio mass spectrometry, ...
and
radiometric dating
Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...
. Mn–Cr isotopic ratios reinforce the evidence from
26Al and
107Pd for the early history of the
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...
. Variations in
53Cr/
52Cr and Mn/Cr ratios from several
meteorite
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the ...
s suggest an initial
53Mn/
55Mn ratio, which indicate that Mn–Cr isotopic composition must result from ''in situ'' decay of
53Mn in differentiated planetary bodies. Hence,
53Mn provides additional evidence for
nucleosynthetic
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons (protons and neutrons) and nuclei. According to current theories, the first nuclei were formed a few minutes after the Big Bang, through nuclear reactions in ...
processes immediately before coalescence of the Solar System.
Chemical compounds
![Chlorid manganatý](https://upload.wikimedia.org/wikipedia/commons/c/c1/Chlorid_manganat%C3%BD.JPG)
Common
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
s of manganese are +2, +3, +4, +6, and +7, although all oxidation states from −3 to +7 have been observed. Manganese in oxidation state +7 is represented by salts of the intensely purple permanganate anion MnO
4−.
Potassium permanganate
Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline salt, that dissolves in water as K+ and , an intensely pink to purple solution.
Potassium permanganate is widely used in the c ...
is a commonly used laboratory
reagent
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...
because of its oxidizing properties; it is used as a topical medicine (for example, in the treatment of fish diseases). Solutions of potassium permanganate were among the first stains and fixatives to be used in the preparation of biological cells and tissues for electron microscopy.
Aside from various permanganate salts, Mn(VII) is represented by the unstable, volatile derivative Mn
2O
7.
Oxyhalide
In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula , where X = fluorine (F), chlor ...
s (MnO
3F and MnO
3Cl) are powerful
oxidizing agents
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxid ...
.
The most prominent example of Mn in the +6 oxidation state is the green anion
manganate
In inorganic nomenclature, a manganate is any negatively charged molecular entity with manganese as the central atom.. However, the name is usually used to refer to the tetraoxidomanganate(2−) anion, MnO, also known as manganate(VI) because it c ...
,
4">nO4sup>2-. Manganate salts are intermediates in the extraction of manganese from its ores. Compounds with oxidation states +5 are somewhat elusive, one example is the blue anion
hypomanganate
In chemistry, hypomanganate, also called manganate(V) or tetraoxidomanganate(3−), is a trivalent anion ( negative ion) composed of manganese and oxygen, with formula .
Hypomanganates are usually bright blue.D. Reinen, W. Rauw, U. Kesper, M. A ...
4">nO4sup>3-.
Compounds with Mn in oxidation state +5 are rarely encountered and often found associated with an oxide (O
2-) or
nitride
In chemistry, a nitride is an inorganic compound of nitrogen. The "nitride" anion, N3- ion, is very elusive but compounds of nitride are numerous, although rarely naturally occuring. Some nitrides have a find applications, such as wear-resistant ...
(N
3-) ligand.
Mn(IV) is somewhat enigmatic because it is common in nature but far rarer in synthetic chemistry. The most common Mn ore,
pyrolusite
Pyrolusite is a mineral consisting essentially of manganese dioxide ( Mn O2) and is important as an ore of manganese.. It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform ...
, is MnO
2. It is the dark brown pigment of many
cave drawing
In archaeology, Cave paintings are a type of parietal art (which category also includes petroglyphs, or engravings), found on the wall or ceilings of caves. The term usually implies prehistoric origin, and the oldest known are more than 40,000 ye ...
s but is also a common ingredient in
dry cell
upLine art drawing of a dry cell: 1. brass cap, 2. plastic seal, 3. expansion space, 4. porous cardboard, 5. zinc can, 6. carbon rod, 7. chemical mixture
A dry cell is a type of electric battery, commonly used for portable electrical devices. Un ...
batteries. Complexes of Mn(IV) are well known, but they require elaborate ligands. Mn(IV)-OH complexes are an intermediate in some
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s, including the oxygen evolving center (OEC) in plants.
Simple derivatives Mn
+3 are rarely encountered but can be stabilized by suitably basic ligands.
Manganese(III) acetate
Manganese(III) acetate describes a family of materials with the approximate formula Mn(O2CCH3)3. These materials are brown solids that are soluble in acetic acid and water. They are used in organic synthesis as oxidizing agents.
Structure
Altho ...
is an oxidant useful in
organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
. Solid compounds of manganese(III) are characterized by its strong purple-red color and a preference for distorted octahedral coordination resulting from the
Jahn-Teller effect.
![KMnO4 in H2O](https://upload.wikimedia.org/wikipedia/commons/4/42/KMnO4_in_H2O.jpg)
A particularly common oxidation state for manganese in aqueous solution is +2, which has a pale pink color. Many manganese(II) compounds are known, such as the
aquo complex
In chemistry, metal aquo complexes are coordination compounds containing metal ions with only water as a ligand. These complexes are the predominant species in aqueous solutions of many metal salts, such as metal nitrates, sulfates, and perchlorat ...
es derived from
manganese(II) sulfate
Manganese(II) sulfate usually refers to the inorganic compound with the formula MnSO4·H2O. This pale pink deliquescent solid is a commercially significant manganese(II) salt. Approximately 260,000 tonnes of manganese(II) sulfate were produced w ...
(MnSO
4) and
manganese(II) chloride
Manganese(II) chloride is the dichloride salt of manganese, MnCl2. This inorganic chemical exists in the anhydrous form, as well as the dihydrate (MnCl2·2H2O) and tetrahydrate (MnCl2·4H2O), with the tetrahydrate being the most common form. Like ...
(MnCl
2). This oxidation state is also seen in the mineral rhodochrosite (
manganese(II) carbonate
Manganese carbonate is a compound with the chemical formula Mn CO3. Manganese carbonate occurs naturally as the mineral rhodochrosite but it is typically produced industrially. It is a pale pink, water-insoluble solid. Approximately 20,000 metr ...
). Manganese(II) commonly exists with a high spin, S = 5/2 ground state because of the high pairing energy for manganese(II). There are no spin-allowed d–d transitions in manganese(II), which explain its faint color.
Organomanganese compounds
Manganese forms a large variety of organometallic derivatives, i.e., compounds with Mn-C bonds. The organometallic derivatives include numerous examples of Mn in its lower oxidation states, i.e. Mn(-III) up through Mn(I). This area of organometallic chemistry is attractive because Mn is inexpensive and of relatively low toxicity.
Of greatest commercial interest is "MMT",
methylcyclopentadienyl manganese tricarbonyl
Methylcyclopentadienyl manganese tricarbonyl (MMT or MCMT) is an organomanganese compound with the formula (C5H4CH3)Mn(CO)3. Initially marketed as a supplement for use in leaded gasoline, MMT was later used in unleaded gasoline to increase the o ...
, which is used as an
anti-knock
An antiknock agent is a gasoline additive used to reduce engine knocking and increase the fuel's octane rating by raising the temperature and pressure at which auto-ignition occurs. The mixture known as gasoline or petrol, when used in high comp ...
compound added to gasoline (petrol) in some countries. It features Mn(I). Consistent with other aspects of Mn(II) chemistry,
manganocene
Manganocene or bis(cyclopentadienyl)manganese(II) is an organomanganese compound with the formula n(C5H5)2sub>n. It is a thermochromic solid that degrades rapidly in air. Although the compound is of little utility, it is often discussed as an ...
() is high-spin. In contrast, its neighboring metal iron forms an air-stable, low-spin derivative in the form of
ferrocene
Ferrocene is an organometallic compound with the formula . The molecule is a complex consisting of two cyclopentadienyl rings bound to a central iron atom. It is an orange solid with a camphor-like odor, that sublimes above room temperature, a ...
(). When conducted under an atmosphere of
carbon monoxide
Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
, reduction of Mn(II) salts gives
dimanganese decacarbonyl
Dimanganese decacarbonyl is the chemical compound with the formula Mn2(CO)10. This metal carbonyl is an important reagent in the organometallic chemistry of manganese.
Synthesis
The compound was first prepared in low yield by the reduction of ...
, an orange and volatile solid. The air-stability of this Mn(0) compound (and its many derivatives) reflects the powerful electron-acceptor properties of carbon monoxide. Many
alkene complex
In organometallic chemistry, a transition metal alkene complex is a coordination compound containing one or more alkene ligands. Such compounds are intermediates in many catalytic reactions that convert alkenes to other organic products.Elschenbro ...
es and
alkyne complex In organometallic chemistry, a transition metal alkyne complex is a coordination compound containing one or more alkyne ligands. Such compounds are intermediates in many catalytic reactions that convert alkynes to other organic products, e.g. hydro ...
es are derived from .
In Mn(CH
3)
2(dmpe)
2, Mn(II) is low spin, which contrasts with the high spin character of its precursor, MnBr
2(dmpe)
2 (
dmpe
1,2-Bis(dimethylphosphino)ethane (dmpe) is a diphosphine ligand in coordination chemistry. It is a colorless, air-sensitive liquid that is soluble in organic solvents. With the formula (CHPMe), dmpe is used as a compact strongly basic spectator l ...
= (CH
3)
2PCH
2CH
2P(CH
3)
2). Polyalkyl and polyaryl derivatives of manganese often exist in higher oxidation states, reflecting the electron-releasing properties of alkyl and aryl ligands. One example is
3)6">n(CH3)6sup>2-.
History
The origin of the name manganese is complex. In ancient times, two black minerals were identified from the regions of the
Magnetes
The Magnetes (Greek: ) were an ancient Greek tribe. In book 2 of the ''Iliad,'' Homer includes them in the Greek Army that is besieging Troy, and identifies their homeland in Thessaly, in a part that is still known as Magnesia. They later also con ...
(either
Magnesia, located within modern Greece, or
Magnesia ad Sipylum
Magnesia Sipylum ( el, Mαγνησία ἡ πρὸς Σιπύλῳ or ; modern Manisa, Turkey) was a city of Lydia, situated about 65 km northeast of Smyrna (now İzmir) on the river Hermus (now Gediz) at the foot of Mount Sipylus. The cit ...
, located within modern Turkey).
They were both called ''magnes'' from their place of origin, but were considered to differ in sex. The male ''magnes'' attracted iron, and was the iron ore now known as
lodestone
Lodestones are naturally magnetized pieces of the mineral magnetite. They are naturally occurring magnets, which can attract iron. The property of magnetism was first discovered in antiquity through lodestones. Pieces of lodestone, suspen ...
or
magnetite
Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the ...
, and which probably gave us the term
magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, ...
. The female ''magnes'' ore did not attract iron, but was used to decolorize glass. This female ''magnes'' was later called ''magnesia'', known now in modern times as
pyrolusite
Pyrolusite is a mineral consisting essentially of manganese dioxide ( Mn O2) and is important as an ore of manganese.. It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform ...
or
manganese dioxide
Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell ...
. Neither this mineral nor elemental manganese is magnetic. In the 16th century, manganese dioxide was called ''manganesum'' (note the two Ns instead of one) by glassmakers, possibly as a corruption and concatenation of two words, since alchemists and glassmakers eventually had to differentiate a ''magnesia nigra'' (the black ore) from ''magnesia alba'' (a white ore, also from Magnesia, also useful in glassmaking).
Michele Mercati
Michele Mercati (8 April 1541 – 25 June 1593) was a physician who was superintendent of the Vatican Botanical Garden under Popes Pius V, Gregory XIII, Sixtus V, and Clement VIII. He was one of the first scholars to recognise prehistoric ston ...
called magnesia nigra ''manganesa'', and finally the metal isolated from it became known as ''manganese'' (German: ''Mangan''). The name ''magnesia'' eventually was then used to refer only to the white
magnesia alba
Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions ...
(magnesium oxide), which provided the name
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
for the free element when it was isolated much later.
Manganese dioxide
Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell ...
, which is abundant in nature, has long been used as a pigment. The cave paintings in
Gargas that are 30,000 to 24,000 years old are made from the mineral form of MnO
2 pigments.
Manganese compounds were used by Egyptian and Roman glassmakers, either to add to, or remove, color from glass. Use as "glassmakers soap" continued through the
Middle Ages
In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
until modern times and is evident in 14th-century glass from
Venice
Venice ( ; it, Venezia ; vec, Venesia or ) is a city in northeastern Italy and the capital of the Veneto Regions of Italy, region. It is built on a group of 118 small islands that are separated by canals and linked by over 400 ...
.
![Gahn Johan Gottlieb](https://upload.wikimedia.org/wikipedia/commons/f/f6/Gahn_Johan_Gottlieb.jpg)
Because it was used in glassmaking,
manganese dioxide
Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell ...
was available for experiments by alchemists, the first chemists.
Ignatius Gottfried Kaim
Ignatius Gottfried Kaim was an Austrian chemist.
In his dissertation ''De metallis dubiis'' published in 1770 Kaim describes the reduction of manganese oxide with carbon and the formation of a brittle metal. This is the first description of mangan ...
(1770) and
Johann Glauber
Johann Rudolf Glauber (10 March 1604 – 16 March 1670) was a German-Dutch alchemy, alchemist and chemist. Some historians of science have described him as one of the first chemical engineers. His discovery of sodium sulfate in 1625 led to t ...
(17th century) discovered that manganese dioxide could be converted to
permanganate
A permanganate () is a chemical compound containing the manganate(VII) ion, , the conjugate base of permanganic acid. Because the manganese atom is in the +7 oxidation state, the permanganate(VII) ion is a strong oxidizing agent. The ion is a tra ...
, a useful laboratory reagent. By the mid-18th century, the Swedish chemist
Carl Wilhelm Scheele
Carl Wilhelm Scheele (, ; 9 December 1742 – 21 May 1786) was a Swedish German pharmaceutical chemist.
Scheele discovered oxygen (although Joseph Priestley published his findings first), and identified molybdenum, tungsten, barium, hydrog ...
used manganese dioxide to produce
chlorine
Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...
. First,
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid
Acid strength is the tendency of an acid, symbol ...
, or a mixture of dilute
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
and
sodium chloride
Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...
was made to react with manganese dioxide, and later hydrochloric acid from the
Leblanc process
The Leblanc process (pronounced leh-blaank) was an early industrial process for making ''soda ash'' (sodium carbonate) used throughout the 19th century, named after its inventor, Nicolas Leblanc. It involved two stages: making sodium sulfate from ...
was used and the manganese dioxide was recycled by the
Weldon process The Weldon process is a process developed in 1866 by Walter Weldon for recovering manganese dioxide for re-use in chlorine manufacture. Commercial operations started at the Gamble works in St. Helens in 1869. The process is described in considera ...
. The production of chlorine and
hypochlorite
In chemistry, hypochlorite is an anion with the chemical formula ClO−. It combines with a number of cations to form hypochlorite salts. Common examples include sodium hypochlorite (household bleach) and calcium hypochlorite (a component of ble ...
bleach
Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...
ing agents was a large consumer of manganese ores.
Scheele and others were aware that pyrolusite (mineral form of
manganese dioxide
Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell ...
) contained a new element.
Johan Gottlieb Gahn
Johan Gottlieb Gahn (19 August 1745 – 8 December 1818) was a Swedish chemist and metallurgist who isolated manganese in 1774.
Gahn studied in Uppsala 1762 – 1770 and became acquainted with chemists Torbern Bergman and Carl Wilhelm Scheele. 177 ...
was the first to isolate an impure sample of manganese metal in 1774, which he did by
reducing the dioxide with
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...
.
The manganese content of some iron ores used in Greece led to speculations that steel produced from that ore contains additional manganese, making the
Sparta
Sparta ( Doric Greek: Σπάρτα, ''Spártā''; Attic Greek: Σπάρτη, ''Spártē'') was a prominent city-state in Laconia, in ancient Greece. In antiquity, the city-state was known as Lacedaemon (, ), while the name Sparta referre ...
n steel exceptionally hard. Around the beginning of the 19th century, manganese was used in steelmaking and several patents were granted. In 1816, it was documented that iron alloyed with manganese was harder but not more brittle. In 1837, British academic
James Couper noted an association between miners' heavy exposure to manganese and a form of
Parkinson's disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
.
In 1912, United States patents were granted for protecting firearms against rust and corrosion with manganese phosphate electrochemical conversion coatings, and the process has seen widespread use ever since.
The invention of the
Leclanché cell
The Leclanché cell is a battery invented and patented by the French scientist Georges Leclanché in 1866. The battery contained a conducting solution (electrolyte) of ammonium chloride, a cathode (positive terminal) of carbon, a depolarizer of m ...
in 1866 and the subsequent improvement of batteries containing manganese dioxide as cathodic
depolarizer
A depolarizer or depolariser, in electrochemistry, according to an IUPAC definition, is a synonym of electroactive substance, i.e., a substance which changes its oxidation state, or partakes in a formation or breaking of chemical bonds, in a ch ...
increased the demand for manganese dioxide. Until the development of batteries with
nickel-cadmium and lithium, most batteries contained manganese. The
zinc–carbon battery
A zinc–carbon battery (or carbon zinc battery in U.S. English) is a dry cell primary battery that provides direct electric current from the electrochemical reaction between zinc and manganese dioxide (MnO2) in the presence of an electrolyte. It ...
and the
alkaline battery
An alkaline battery (IEC code: L) is a type of primary battery where the electrolyte (most commonly potassium hydroxide) has a pH value above 7. Typically these batteries derive energy from the reaction between zinc metal and manganese dioxide, ...
normally use industrially produced manganese dioxide because naturally occurring manganese dioxide contains impurities. In the 20th century,
manganese dioxide
Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell ...
was widely used as the cathodic for commercial disposable dry batteries of both the standard (zinc–carbon) and alkaline types.
Occurrence
Manganese comprises about 1000
ppm (0.1%) of the
Earth's crust
Earth's crust is Earth's thin outer shell of rock, referring to less than 1% of Earth's radius and volume. It is the top component of the lithosphere, a division of Earth's layers that includes the crust and the upper part of the mantle. The ...
, the 12th most abundant of the crust's elements.
Soil contains 7–9000 ppm of manganese with an average of 440 ppm.
The atmosphere contains 0.01 μg/m
3.
Manganese occurs principally as
pyrolusite
Pyrolusite is a mineral consisting essentially of manganese dioxide ( Mn O2) and is important as an ore of manganese.. It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform ...
(
MnO2),
braunite
Braunite is a silicate mineral containing both di- and tri- valent manganese with the chemical formula:
Mn2+Mn3+6 SiO4 Common impurities include iron, calcium, boron, barium, titanium, aluminium, and magnesium.
Braunite forms grey/black tetragon ...
(Mn
2+Mn
3+6)SiO
12),
psilomelane
Psilomelane is a group name for hard black manganese oxides including hollandite and romanechite. Psilomelane consists of hydrous manganese oxide with variable amounts of barium and potassium. Psilomelane is erroneously, and uncommonly, known as ...
, and to a lesser extent as
rhodochrosite
Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its (rare) pure form, it is typically a rose-red color, but impure specimens can be shades of pink to pale brown. It streaks white, and its Mohs hardness varies bet ...
(
MnCO3).
![World Manganese Production 2006](https://upload.wikimedia.org/wikipedia/commons/2/24/World_Manganese_Production_2006.svg)
The most important manganese ore is pyrolusite (
MnO2). Other economically important manganese ores usually show a close spatial relation to the iron ores, such as
sphalerite
Sphalerite (sometimes spelled sphaelerite) is a sulfide mineral with the chemical formula . It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in Sedimentary exhalative deposits, sedimen ...
.
Land-based resources are large but irregularly distributed. About 80% of the known world manganese resources are in South Africa; other important manganese deposits are in Ukraine, Australia, India, China,
Gabon
Gabon (; ; snq, Ngabu), officially the Gabonese Republic (french: République gabonaise), is a country on the west coast of Central Africa. Located on the equator, it is bordered by Equatorial Guinea to the northwest, Cameroon to the north ...
and Brazil.
According to 1978 estimate, the
ocean floor
The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'.
The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
has 500 billion tons of
manganese nodule
Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, de ...
s. Attempts to find economically viable methods of harvesting manganese nodules were abandoned in the 1970s.
In South Africa, most identified deposits are located near
Hotazel
Hotazel is a town in John Taolo Gaetsewe District Municipality in the Northern Cape province of South Africa.
The town serves the manganese mines, 147 km (91 mi) north of Postmasburg and 46 km (28.6 mi) north-west of Kuruman
...
in the
Northern Cape Province
The Northern Cape is the largest and most sparsely populated province of South Africa. It was created in 1994 when the Cape Province was split up. Its capital is Kimberley, South Africa, Kimberley. It includes the Kalahari Gemsbok National Park, ...
, with a 2011 estimate of 15 billion tons. In 2011 South Africa produced 3.4 million tons, topping all other nations.
Manganese is mainly mined in South Africa, Australia, China, Gabon, Brazil, India, Kazakhstan, Ghana, Ukraine and Malaysia.
Production
For the production of
ferromanganese
Ferromanganese is a ferroalloy with high manganese content (high-carbon ferromanganese can contain as much as 80% Mn by weight). It is made by heating a mixture of the oxides MnO2 and Fe2O3, with carbon (usually as coal and coke) in either a bla ...
, the manganese ore is mixed with iron ore and carbon, and then reduced either in a blast furnace or in an electric arc furnace.
The resulting
ferromanganese
Ferromanganese is a ferroalloy with high manganese content (high-carbon ferromanganese can contain as much as 80% Mn by weight). It is made by heating a mixture of the oxides MnO2 and Fe2O3, with carbon (usually as coal and coke) in either a bla ...
has a manganese content of 30 to 80%.
Pure manganese used for the production of iron-free alloys is produced by
leaching
Leaching is the loss or extraction of certain materials from a carrier into a liquid (usually, but not always a solvent). and may refer to:
* Leaching (agriculture), the loss of water-soluble plant nutrients from the soil; or applying a small amou ...
manganese ore with
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
and a subsequent
electrowinning
Electrowinning, also called electroextraction, is the electrodeposition of metals from their ores that have been put in solution via a process commonly referred to as leaching. Electrorefining uses a similar process to remove impurities from a ...
process.
![Manganese Process Flow Diagram](https://upload.wikimedia.org/wikipedia/commons/8/81/Manganese_Process_Flow_Diagram.jpg)
A more progressive extraction process involves directly reducing (a low grade) manganese ore by
heap leaching
Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical reactions that absorb specific minerals and re-separate them after their division from other e ...
. This is done by
percolating
Percolation (from Latin ''percolare'', "to filter" or "trickle through"), in physics, chemistry and materials science, refers to the movement and filtering of fluids through porous materials.
It is described by Darcy's law.
Broader application ...
natural gas through the bottom of the heap; the natural gas provides the heat (needs to be at least 850 °C) and the reducing agent (carbon monoxide). This reduces all of the manganese ore to manganese oxide (MnO), which is a leachable form. The ore then travels through a
grinding
Grind is the cross-sectional shape of a blade.
Grind, grinds, or grinding may also refer to:
Grinding action
* Grinding (abrasive cutting), a method of crafting
* Grinding (dance), suggestive club dancing
* Grinding (video gaming), repetitive and ...
circuit to reduce the particle size of the ore to between 150 and 250 μm, increasing the surface area to aid leaching. The ore is then added to a leach tank of
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
and
ferrous iron
In chemistry, iron(II) refers to the element iron in its +2 oxidation state. In ionic compounds (salts), such an atom may occur as a separate cation (positive ion) denoted by Fe2+.
The adjective ferrous or the prefix ferro- is often used to spe ...
(Fe
2+) in a 1.6:1 ratio. The iron reacts with the
manganese dioxide
Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell ...
(MnO
2) to form
iron hydroxide
Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. All are black magnetic solids. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of which ...
(FeO(OH)) and elemental manganese (Mn):
This process yields approximately 92% recovery of the manganese. For further purification, the manganese can then be sent to an electrowinning facility.
In 1972 the
CIA
The Central Intelligence Agency (CIA ), known informally as the Agency and historically as the Company, is a civilian intelligence agency, foreign intelligence service of the federal government of the United States, officially tasked with gat ...
's
Project Azorian
Project Azorian (also called "Jennifer" by the press after its Top Secret Security Compartment) was a U.S. Central Intelligence Agency (CIA) project to recover the sunken Soviet submarine ''K-129'' from the Pacific Ocean floor in 1974, using th ...
, through billionaire
Howard Hughes
Howard Robard Hughes Jr. (December 24, 1905 – April 5, 1976) was an American business magnate, record-setting pilot, engineer, film producer, and philanthropist, known during his lifetime as one of the most influential and richest people in th ...
, commissioned the ship ''
Hughes Glomar Explorer
''GSF Explorer'', formerly USNS ''Hughes Glomar Explorer'' (T-AG-193), was a deep-sea drillship platform built for Project Azorian, the secret 1974 effort by the United States Central Intelligence Agency's Special Activities Division to recover ...
'' with the cover story of harvesting manganese nodules from the sea floor. That triggered a rush of activity to collect manganese nodules, which was not actually practical. The real mission of ''Hughes Glomar Explorer'' was to raise a sunken
Soviet
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
submarine, the
K-129
''K-129'' (Russian: К–129) was a Project 629A (Russian: проект 629А ''Projekt 629A'', NATO reporting name Golf II–class) diesel-electric- powered ballistic-missile submarine that served in the Pacific Fleet of the Soviet Navy ...
, with the goal of retrieving Soviet code books.
An abundant resource of manganese in the form of
Mn nodules found on the ocean floor. These nodules, which are composed of 29% manganese, are located along the
ocean floor
The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'.
The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
and the potential impact of mining these nodules is being researched. Physical, chemical, and biological environmental impacts can occur due to this nodule mining disturbing the seafloor and causing sediment plumes to form. This suspension includes metals and inorganic nutrients, which can lead to contamination of the near-bottom waters from dissolved toxic compounds. Mn nodules are also the grazing grounds, living space, and protection for endo- and epifaunal systems. When theses nodules are removed, these systems are directly affected. Overall, this can cause species to leave the area or completely die off. Prior to the commencement of the mining itself, research is being conducted by
United Nations
The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and international security, security, develop friendly relations among nations, achieve international cooperation, and be ...
affiliated bodies and state-sponsored companies in an attempt to fully understand
environmental impacts
Environmental issues are effects of human activity on the biophysical environment, most often of which are harmful effects that cause environmental degradation. Environmental protection is the practice of protecting the natural environment on t ...
in the hopes of mitigating these impacts.
Oceanic environment
Many trace elements in the ocean come from metal-rich hydrothermal particles from hydrothermal vents.
Dissolved manganese (dMn) is found throughout the world's oceans, 90% of which originates from hydrothermal vents.
Particulate Mn develops in buoyant plumes over an active vent source, while the dMn behaves conservatively.
Mn concentrations vary between the water columns of the ocean. At the surface, dMn is elevated due to input from external sources such as rivers, dust, and shelf sediments. Coastal sediments normally have lower Mn concentrations, but can increase due to anthropogenic discharges from industries such as mining and steel manufacturing, which enter the ocean from river inputs. Surface dMn concentrations can also be elevated biologically through photosynthesis and physically from coastal upwelling and wind-driven surface currents. Internal cycling such as photo-reduction from UV radiation can also elevate levels by speeding up the dissolution of Mn-oxides and oxidative scavenging, preventing Mn from sinking to deeper waters.
Elevated levels at mid-depths can occur near mid-ocean ridges and hydrothermal vents. The hydrothermal vents release dMn enriched fluid into the water. The dMn can then travel up to 4,000 km due to the microbial capsules present, preventing exchange with particles, lowing the sinking rates. Dissolved Mn concentrations are even higher when oxygen levels are low. Overall, dMn concentrations are normally higher in coastal regions and decrease when moving offshore.
Soils
Manganese occurs in soils in three oxidation states: the divalent cation, Mn
2+ and as brownish-black oxides and hydroxides containing Mn (III,IV), such as MnOOH and MnO
2. Soil pH and oxidation-reduction conditions affect which of these three forms of Mn is dominant in a given soil. At pH values less than 6 or under anaerobic conditions, Mn(II) dominates, while under more alkaline and aerobic conditions, Mn(III,IV) oxides and hydroxides predominate. These effects of soil acidity and aeration state on the form of Mn can be modified or controlled by microbial activity. Microbial respiration can cause both the oxidation of Mn
2+ to the oxides, and it can cause reduction of the oxides to the divalent cation.
The Mn(III,IV) oxides exist as brownish-black stains and small nodules on sand, silt, and clay particles. These surface coatings on other soil particles have high surface area and carry negative charge. The charged sites can adsorb and retain various cations, especially heavy metals (e.g., Cr
3+, Cu
2+, Zn
2+, and Pb
2+). In addition, the oxides can adsorb organic acids and other compounds. The adsorption of the metals and organic compounds can then cause them to be oxidized while the Mn(III,IV) oxides are reduced to Mn
2+ (e.g., Cr
3+ to Cr(VI) and colorless hydroquinone to tea-colored quinone polymers).
Applications
Manganese has no satisfactory substitute in its major applications in metallurgy.
In minor applications (e.g., manganese phosphating),
zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
and sometimes
vanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer ( pas ...
are viable substitutes.
Steel
![M1917helmet](https://upload.wikimedia.org/wikipedia/commons/8/89/M1917helmet.jpg)
Manganese is essential to iron and
steel production
Steelmaking is the process of producing steel from iron ore and carbon/or scrap. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon (the most important impurity) are removed from the sourced iron, and ...
by virtue of its sulfur-fixing,
deoxidizing
Deoxidization is a method used in metallurgy to remove the oxygen content during steel manufacturing. In contrast, antioxidants are used for stabilization, such as in the storage of food. Deoxidation is important in the steelmaking process as o ...
, and
alloying
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility ...
properties, as first recognized by the British metallurgist
Robert Forester Mushet
Robert Forester Mushet (8 April 1811 – 29 January 1891) was a British metallurgist and businessman, born on 8 April 1811, in Coleford, in the Forest of Dean, Gloucestershire, England. He was the youngest son of Scottish parents, Agnes Wilson ...
(1811–1891) who, in 1856, introduced the element, in the form of
Spiegeleisen
Spiegeleisen (literally "mirror-iron", —mirror or specular; —iron) is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon. Spiegeleisen is sometimes also referred to as ''specular pig iron' ...
, into steel for the specific purpose of removing excess dissolved oxygen, sulfur, and phosphorus in order to improve its malleability.
Steelmaking
Steelmaking is the process of producing steel from iron ore and carbon/or scrap. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon (the most important impurity) are removed from the sourced iron, and all ...
, including its ironmaking component, has accounted for most manganese demand, presently in the range of 85% to 90% of the total demand.
Manganese is a key component of low-cost
stainless steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
.
[Manganese USGS 2006] Often
ferromanganese
Ferromanganese is a ferroalloy with high manganese content (high-carbon ferromanganese can contain as much as 80% Mn by weight). It is made by heating a mixture of the oxides MnO2 and Fe2O3, with carbon (usually as coal and coke) in either a bla ...
(usually about 80% manganese) is the intermediate in modern processes.
Small amounts of manganese improve the workability of steel at high temperatures by forming a high-melting sulfide and preventing the formation of a liquid
iron sulfide
Iron sulfide or Iron sulphide can refer to range of chemical compounds composed of iron and sulfur.
Minerals
By increasing order of stability:
* Iron(II) sulfide, FeS
* Greigite, Fe3S4 (cubic)
* Pyrrhotite, Fe1−xS (where x = 0 to 0.2) (monoclin ...
at the grain boundaries. If the manganese content reaches 4%, the embrittlement of the steel becomes a dominant feature. The embrittlement decreases at higher manganese concentrations and reaches an acceptable level at 8%. Steel containing 8 to 15% of manganese has a high
tensile strength
Ultimate tensile strength (UTS), often shortened to tensile strength (TS), ultimate strength, or F_\text within equations, is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials t ...
of up to 863 MPa. Steel with 12% manganese was discovered in 1882 by
Robert Hadfield
Sir Robert Abbott Hadfield, 1st Baronet FRS (28 November 1858 in Sheffield – 30 September 1940 in Surrey) was an English metallurgist, noted for his 1882 discovery of manganese steel, one of the first steel alloys. He also invented silicon s ...
and is still known as
Hadfield steel (mangalloy). It was used for British military
steel helmets and later by the U.S. military.
Aluminium alloys
Manganese is used in production of alloys with aluminium. Aluminium with roughly 1.5% manganese has increased resistance to corrosion through grains that absorb impurities which would lead to
galvanic corrosion
Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion) is an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, in the presence of an electrolyte. A sim ...
. The corrosion-resistant
aluminium alloy
An aluminium alloy (or aluminum alloy; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principal ...
s 3004 and 3104 (0.8 to 1.5% manganese) are used for most
beverage can
A drink can (or beverage can) is a metal container designed to hold a fixed portion of liquid such as carbonated soft drinks, alcoholic drinks, fruit juices, teas, herbal teas, energy drinks, etc. Drink cans are made of aluminum (75% of w ...
s.
Before 2000, more than 1.6 million
tonne
The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
s of those alloys were used; at 1% manganese, this consumed 16,000 tonnes of manganese.
Batteries
Manganese(IV) oxide
Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cel ...
was used in the original type of dry cell
battery
Battery most often refers to:
* Electric battery, a device that provides electrical power
* Battery (crime), a crime involving unlawful physical contact
Battery may also refer to:
Energy source
*Automotive battery, a device to provide power t ...
as an electron acceptor from zinc, and is the blackish material in carbon–zinc type flashlight cells. The manganese dioxide is reduced to the manganese oxide-hydroxide MnO(OH) during discharging, preventing the formation of hydrogen at the anode of the battery.
:MnO
2 + H
2O + e
− → MnO(OH) +
The same material also functions in newer
alkaline batteries
An alkaline battery (IEC code: L) is a type of primary battery where the electrolyte (most commonly potassium hydroxide) has a pH value above 7. Typically these batteries derive energy from the reaction between zinc metal and manganese dioxi ...
(usually battery cells), which use the same basic reaction, but a different electrolyte mixture. In 2002, more than 230,000 tons of manganese dioxide was used for this purpose.
Resistors
Copper alloys of manganese, such as
Manganin
Manganin is a trademarked name for an alloy of typically 84.2% copper, 12.1% manganese, and 3.7% nickel. It was first developed by Edward Weston in 1892, improving upon his Constantan (1887).
Manganin foil and wire is used in the manufacture of ...
, are commonly found in metal element
shunt resistor
In electronics, a shunt is a device that creates a low- resistance path for electric current, to allow it to pass around another point in the circuit.Rudolf F. Graf, ''Modern dictionary of Electronics'', Mc-Graw Hill, 1968 Library of Congress 68- ...
s used for measuring relatively large amounts of current. These alloys have very low
temperature coefficient of resistance
A temperature coefficient describes the relative change of a physical property that is associated with a given change in temperature. For a property ''R'' that changes when the temperature changes by ''dT'', the temperature coefficient α is def ...
and are resistant to sulfur. This makes the alloys particularly useful in harsh automotive and industrial environments.
Niche
Methylcyclopentadienyl manganese tricarbonyl
Methylcyclopentadienyl manganese tricarbonyl (MMT or MCMT) is an organomanganese compound with the formula (C5H4CH3)Mn(CO)3. Initially marketed as a supplement for use in leaded gasoline, MMT was later used in unleaded gasoline to increase the o ...
is an additive in some
unleaded gasoline
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most Spark-ignition engine, spark-ignited internal combustion engines (also known as petrol engines). It consists ...
to boost
octane rating
An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating ...
and reduce
engine knocking
In spark ignition internal combustion engines, knocking (also knock, detonation, spark knock, pinging or pinking) occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignite ...
.
Manganese(IV) oxide
Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cel ...
(manganese dioxide, MnO
2) is used as a reagent in
organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; ...
for the
oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
of benzylic
alcohol
Alcohol most commonly refers to:
* Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom
* Alcohol (drug), an intoxicant found in alcoholic drinks
Alcohol may also refer to:
Chemicals
* Ethanol, one of sev ...
s (where the
hydroxyl
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...
group is adjacent to an
aromatic ring
In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to saturat ...
). Manganese dioxide has been used since antiquity to oxidize and neutralize the greenish tinge in glass from trace amounts of iron contamination.
MnO
2 is also used in the manufacture of oxygen and chlorine and in drying black paints. In some preparations, it is a brown
pigment
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...
for
paint
Paint is any pigmented liquid, liquefiable, or solid mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture. Paint can be made in many ...
and is a constituent of natural
umber
Umber is a natural brown earth pigment that contains iron oxide and manganese oxide. In its natural form, it is called raw umber. When Calcination, calcined, the color becomes warmer and it becomes known as burnt umber.
Its name derives from '' ...
.
Tetravalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules.
Description
The combining capacity, or affinity of an ...
manganese is used as an
activator in red-emitting
phosphor
A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or vi ...
s. While many compounds are known which show
luminescence
Luminescence is spontaneous emission of light by a substance not resulting from heat; or "cold light".
It is thus a form of cold-body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions or stress on a cryst ...
, the majority are not used in commercial application due to low efficiency or deep red emission. However, several Mn
4+ activated fluorides were reported as potential red-emitting phosphors for warm-white LEDs. But to this day, only K
2SiF
6:Mn
4+ is commercially available for use in warm-white
LED
A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
s.
The metal is occasionally used in coins; until 2000, the only United States coin to use manganese was the
"wartime" nickel from 1942 to 1945. An alloy of 75% copper and 25% nickel was traditionally used for the production of nickel coins. However, because of shortage of nickel metal during the war, it was substituted by more available silver and manganese, thus resulting in an alloy of 56% copper, 35% silver and 9% manganese. Since 2000,
dollar coins, for example the
Sacagawea dollar
The Sacagawea dollar (also known as the "golden dollar") is a United States dollar coin introduced in 2000, although not minted for general circulation between 2002 to 2008 and again from 2012 onward because of its general unpopularity with th ...
and the
Presidential $1 coins, are made from a brass containing 7% of manganese with a pure copper core. In both cases of nickel and dollar, the use of manganese in the coin was to duplicate the electromagnetic properties of a previous identically sized and valued coin in the mechanisms of vending machines. In the case of the later U.S. dollar coins, the manganese alloy was intended to duplicate the properties of the copper/nickel alloy used in the previous
Susan B. Anthony dollar
The Susan B. Anthony dollar is a United States dollar coin minted from 1979 to 1981 when production was suspended due to poor public acceptance, and then again in 1999. Intended as a replacement for the larger Eisenhower dollar, the new smalle ...
.
Manganese compounds have been used as pigments and for the coloring of ceramics and glass. The brown color of ceramic is sometimes the result of manganese compounds. In the glass industry, manganese compounds are used for two effects.
Manganese(III) reacts with
iron(II)
In chemistry, iron(II) refers to the element iron in its +2 oxidation state. In ionic compounds (salts), such an atom may occur as a separate cation (positive ion) denoted by Fe2+.
The adjective ferrous or the prefix ferro- is often used to spe ...
to reduce strong green color in glass by forming less-colored iron(III) and slightly pink manganese(II), compensating for the residual color of the iron(III).
Larger quantities of manganese are used to produce pink colored glass. In 2009, Professor
Mas Subramanian
Mas Subramanian, (born 1954), is a solid-state materials scientist at Oregon State University in Corvallis, Oregon. He is a University Distinguished Professor and the Milton Harris Chair of Materials Science in the university's Department of ...
and associates at
Oregon State University
Oregon State University (OSU) is a public land-grant, research university in Corvallis, Oregon. OSU offers more than 200 undergraduate-degree programs along with a variety of graduate and doctoral degrees. It has the 10th largest engineering co ...
discovered that manganese can be combined with
yttrium
Yttrium is a chemical element with the symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element". Yttrium is almost always found in com ...
and
indium
Indium is a chemical element with the symbol In and atomic number 49. Indium is the softest metal that is not an alkali metal. It is a silvery-white metal that resembles tin in appearance. It is a post-transition metal that makes up 0.21 parts p ...
to form an intensely
blue
Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when obs ...
, non-toxic, inert, fade-resistant
pigment
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...
,
YInMn blue, the first new blue pigment discovered in 200 years.
Biological role
Biochemistry
The classes of
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s that have manganese
cofactors
Cofactor may also refer to:
* Cofactor (biochemistry), a substance that needs to be present in addition to an enzyme for a certain reaction to be catalysed
* A domain parameter in elliptic curve cryptography, defined as the ratio between the order ...
include
oxidoreductase
In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually ut ...
s,
transferase
A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of di ...
s,
hydrolase
Hydrolase is a class of enzyme that commonly perform as biochemical catalysts that use water to break a chemical bond, which typically results in dividing a larger molecule into smaller molecules. Some common examples of hydrolase enzymes are este ...
s,
lyase
In biochemistry, a lyase is an enzyme that catalyzes the breaking (an elimination reaction) of various chemical bonds by means other than hydrolysis (a substitution reaction) and oxidation, often forming a new double bond or a new ring structure. ...
s,
isomerase
Isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which bonds are broken and formed. The general form of such a reaction is as follows:
A–B ...
s and
ligase
In biochemistry, a ligase is an enzyme that can catalyze the joining (ligation) of two large molecules by forming a new chemical bond. This is typically via hydrolysis of a small pendant chemical group on one of the larger molecules or the enzym ...
s. Other enzymes containing manganese are
arginase
Arginase (, ''arginine amidinase'', ''canavanase'', ''L-arginase'', ''arginine transamidinase'') is a manganese-containing enzyme. The reaction catalyzed by this enzyme is:
: arginine + H2O → ornithine + urea
It is the final enzyme of the ure ...
and Mn-containing
superoxide dismutase
Superoxide dismutase (SOD, ) is an enzyme that alternately catalyzes the dismutation (or partitioning) of the superoxide () radical into ordinary molecular oxygen (O2) and hydrogen peroxide (). Superoxide is produced as a by-product of oxygen me ...
(
Mn-SOD). Also the enzyme class of
reverse transcriptase
A reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription. Reverse transcriptases are used by viruses such as HIV and hepatitis B to replicate their genomes, ...
s of many
retrovirus
A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. Once inside the host cell's cytoplasm, the virus uses its own reverse transcriptase ...
es (though not
lentivirus
''Lentivirus'' is a genus of retroviruses that cause chronic and deadly diseases characterized by long incubation periods, in humans and other mammalian species. The genus includes the human immunodeficiency virus (HIV), which causes AIDS. Lent ...
es such as
HIV
The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...
) contains manganese. Manganese-containing
polypeptides
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides.
A p ...
are the
diphtheria toxin
Diphtheria toxin is an exotoxin secreted by '' Corynebacterium diphtheriae'', the pathogenic bacterium that causes diphtheria. The toxin gene is encoded by a prophageA prophage is a virus that has inserted itself into the genome of the host ...
,
lectin
Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in rec ...
s and
integrin
Integrins are transmembrane receptors that facilitate cell-cell and cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, ...
s.
Biological role in humans
Manganese is an essential human dietary element. It is present as a
coenzyme
A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's role as a catalyst (a catalyst is a substance that increases the rate of a chemical reaction). Cofactors can be considered "helper molecules" that ass ...
in several biological processes, which include macronutrient metabolism, bone formation, and
free radical
A daughter category of ''Ageing'', this category deals only with the biological aspects of ageing.
Ageing
Ailments of unknown cause
Biogerontology
Biological processes
Causes of death
Cellular processes
Gerontology
Life extension
Metabo ...
defense systems. It is a critical component in dozens of proteins and enzymes.
[
] The human body contains about 12 mg of manganese, mostly in the bones. The soft tissue remainder is concentrated in the liver and kidneys.
In the human brain, the manganese is bound to manganese
metalloprotein
Metalloprotein is a generic term for a protein that contains a metal ion Cofactor (biochemistry), cofactor. A large proportion of all proteins are part of this category. For instance, at least 1000 human proteins (out of ~20,000) contain zinc-bi ...
s, most notably
glutamine synthetase
Glutamine synthetase (GS) () is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine:
Glutamate + Adenosine triphosphate, ATP + NH3 → Glutamine + Ad ...
in
astrocyte
Astrocytes (from Ancient Greek , , "star" + , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of endo ...
s.
Nutrition
The
U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for minerals in 2001. For manganese there was not sufficient information to set EARs and RDAs, so needs are described as estimates for
Adequate Intake
The Dietary Reference Intake (DRI) is a system of nutrition recommendations from the National Academy of Medicine (NAM) of the National Academies (United States). It was introduced in 1997 in order to broaden the existing guidelines known as Reco ...
s (AIs). As for safety, the IOM sets
Tolerable upper intake level
The Dietary Reference Intake (DRI) is a system of nutrition recommendations from the National Academy of Medicine (NAM) of the National Academies (United States). It was introduced in 1997 in order to broaden the existing guidelines known as Reco ...
s (ULs) for vitamins and minerals when evidence is sufficient. In the case of manganese the adult UL is set at 11 mg/day. Collectively the EARs, RDAs, AIs and ULs are referred to as
Dietary Reference Intake
The Dietary Reference Intake (DRI) is a system of nutrition recommendations from the National Academy of Medicine (NAM) of the National Academies (United States). It was introduced in 1997 in order to broaden the existing guidelines known as Reco ...
s (DRIs).
Manganese deficiency is rare.
The
European Food Safety Authority
The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002, ...
(EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. For people ages 15 and older the AI is set at 3.0 mg/day. AIs for pregnancy and lactation is 3.0 mg/day. For children ages 1–14 years the AIs increase with age from 0.5 to 2.0 mg/day. The adult AIs are higher than the U.S. RDAs. The EFSA reviewed the same safety question and decided that there was insufficient information to set a UL.
For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For manganese labeling purposes 100% of the Daily Value was 2.0 mg, but as of 27 May 2016 it was revised to 2.3 mg to bring it into agreement with the RDA.
A table of the old and new adult daily values is provided at
Reference Daily Intake
The Reference Daily Intake (RDI) used in nutrition labeling on food and dietary supplement products in the U.S. and Canada is the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97–98% of health ...
.
Excessive exposure or intake may lead to a condition known as
manganism
Manganism or manganese poisoning is a toxic condition resulting from chronic exposure to manganese. It was first identified in 1837 by James Couper.
Signs and symptoms
Chronic exposure to excessive manganese levels can lead to a variety of psyc ...
, a
neurodegenerative
A neurodegenerative disease is caused by the progressive loss of structure or function of neurons, in the process known as neurodegeneration. Such neuronal damage may ultimately involve cell death. Neurodegenerative diseases include amyotrophic ...
disorder that causes
dopamine
Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic compound, organic chemical of the catecholamine and phenethylamine families. Dopamine const ...
rgic neuronal death and symptoms similar to
Parkinson's disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
.
Deficiency
Manganese deficiency in humans, which is rare, results in a number of medical problems. A deficiency of manganese causes skeletal deformation in animals and inhibits the production of collagen in wound healing.
Toxicity in marine life
Many enzymatic systems need Mn to function, but in high levels, Mn can become toxic. One environmental reason Mn levels can increase in seawater is when hypoxic periods occur. Since 1990 there have been reports of Mn accumulation in marine organisms including fish, crustaceans, mollusks, and echinoderms. Specific tissues are targets in different species, including the gills, brain, blood, kidney, and liver/hepatopancreas. Physiological effects have been reported in these species. Mn can affect the renewal of immunocytes and their functionality, such as phagocytosis and activation of pro-phenoloxidase, suppressing the organisms' immune systems. This causes the organisms to be more susceptible to infections. As climate change occurs, pathogen distributions increase, and in order for organisms to survive and defend themselves against these pathogens, they need a healthy, strong immune system. If their systems are compromised from high Mn levels, they will not be able to fight off these pathogens and die.
Biological role in bacteria
Mn-SOD is the type of SOD present in
eukaryotic
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...
mitochondria
A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...
, and also in most bacteria (this fact is in keeping with the bacterial-origin theory of mitochondria). The Mn-SOD enzyme is probably one of the most ancient, for nearly all organisms living in the presence of oxygen use it to deal with the toxic effects of
superoxide
In chemistry, a superoxide is a compound that contains the superoxide ion, which has the chemical formula . The systematic name of the anion is dioxide(1−). The reactive oxygen ion superoxide is particularly important as the product of the ...
(), formed from the 1-electron reduction of dioxygen. The exceptions, which are all bacteria, include ''
Lactobacillus plantarum
''Lactiplantibacillus plantarum'' (formerly ''Lactobacillus arabinosus'' and ''Lactobacillus plantarum'') is a widespread member of the genus ''Lactiplantibacillus'' and commonly found in many fermented food products as well as anaerobic plant ma ...
'' and related
lactobacilli
The ''Lactobacillaceae'' are a family of lactic acid bacteria. It is the only family in the lactic acid bacteria which includes homofermentative and heterofermentative organisms; in the ''Lactobacillaceae,'' the pathway used for hexose fermentati ...
, which use a different nonenzymatic mechanism with manganese (Mn
2+) ions complexed with polyphosphate, suggesting a path of evolution for this function in aerobic life.
Biological role in plants
Manganese is also important in photosynthetic
oxygen evolution
Oxygen evolution is the process of generating molecular oxygen (O2) by a chemical reaction, usually from water. Oxygen evolution from water is effected by oxygenic photosynthesis, electrolysis of water, and thermal decomposition of various oxides. ...
in
chloroplast
A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in ...
s in plants. The
oxygen-evolving complex
The oxygen-evolving complex (OEC), also known as the water-splitting complex, is the portion of photosystem II where photo-oxidation of water occurs during the light reactions of photosynthesis. The OEC is surrounded by four core protein subuni ...
(OEC) is a part of photosystem II contained in the thylakoid membranes of chloroplasts; it is responsible for the terminal
photooxidation of water during the
light reactions
Light-dependent reactions is jargon for certain photochemical reactions that are involved in photosynthesis, the main process by which plants acquire energy. There are two light dependent reactions, the first occurs at photosystem II (PSII) and ...
of
photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
, and has a metalloenzyme core containing four atoms of manganese. To fulfill this requirement, most broad-spectrum plant fertilizers contain manganese.
Precautions
Manganese compounds are less toxic than those of other widespread metals, such as
nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...
and
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
. However, exposure to manganese dusts and fumes should not exceed the ceiling value of 5 mg/m
3 even for short periods because of its toxicity level. Manganese poisoning has been linked to impaired motor skills and cognitive disorders.
Permanganate exhibits a higher toxicity than manganese(II) compounds. The fatal dose is about 10 g, and several fatal intoxications have occurred. The strong oxidative effect leads to
necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...
of the
mucous membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...
. For example, the
esophagus
The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the ...
is affected if the permanganate is swallowed. Only a limited amount is absorbed by the intestines, but this small amount shows severe effects on the kidneys and on the liver.
Manganese exposure in
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
is regulated by the
Occupational Safety and Health Administration
The Occupational Safety and Health Administration'' (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agenc ...
(OSHA).
People can be exposed to manganese in the workplace by breathing it in or swallowing it. OSHA has set the legal limit (
permissible exposure limit
The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits are established by the Occupational S ...
) for manganese exposure in the workplace as 5 mg/m
3 over an 8-hour workday. The
National Institute for Occupational Safety and Health
The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the C ...
(NIOSH) has set a
recommended exposure limit
A recommended exposure limit (REL) is an occupational exposure limit that has been recommended by the United States National Institute for Occupational Safety and Health. The REL is a level that NIOSH believes would be protective of worker safety ...
(REL) of 1 mg/m
3 over an 8-hour workday and a short term limit of 3 mg/m
3. At levels of 500 mg/m
3, manganese is
immediately dangerous to life and health
The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent advers ...
.
Generally, exposure to ambient Mn air concentrations in excess of 5 μg Mn/m3 can lead to Mn-induced symptoms. Increased
ferroportin
Ferroportin-1, also known as solute carrier family 40 member 1 (SLC40A1) or iron-regulated transporter 1 (IREG1), is a protein that in humans is encoded by the ''SLC40A1'' gene, and is part of the Ferroportin (Fpn) FamilyTC# 2.A.100. Ferroportin i ...
protein expression in human embryonic kidney (HEK293) cells is associated with decreased intracellular Mn concentration and attenuated
cytotoxicity
Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are an immune cell or some types of venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa'').
Cell physiology
Treating cells ...
, characterized by the reversal of Mn-reduced
glutamate
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...
uptake and diminished
lactate dehydrogenase
Lactate dehydrogenase (LDH or LD) is an enzyme found in nearly all living cells. LDH catalyzes the conversion of lactate to pyruvate and back, as it converts NAD+ to NADH and back. A dehydrogenase is an enzyme that transfers a hydride from on ...
leakage.
Environmental health concerns
In drinking water
Waterborne manganese has a greater
bioavailability
In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation.
By definition, when a medication is administered intravenously, its bioavailability is 100%. H ...
than dietary manganese. According to results from a 2010 study,
higher levels of exposure to manganese in
drinking water
Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...
are associated with increased
intellectual impairment
Developmental disability is a diverse group of chronic conditions, comprising mental or physical impairments that arise before adulthood. Developmental disabilities cause individuals living with them many difficulties in certain areas of life, espe ...
and reduced
intelligence quotient
An intelligence quotient (IQ) is a total score derived from a set of standardized tests or subtests designed to assess human intelligence. The abbreviation "IQ" was coined by the psychologist William Stern for the German term ''Intelligenzqu ...
s in school-age children. It is hypothesized that long-term exposure due to inhaling the naturally occurring manganese in shower water puts up to 8.7 million Americans at risk. However, data indicates that the human body can recover from certain adverse effects of overexposure to manganese if the exposure is stopped and the body can clear the excess.
In gasoline
Methylcyclopentadienyl manganese tricarbonyl
Methylcyclopentadienyl manganese tricarbonyl (MMT or MCMT) is an organomanganese compound with the formula (C5H4CH3)Mn(CO)3. Initially marketed as a supplement for use in leaded gasoline, MMT was later used in unleaded gasoline to increase the o ...
(MMT) is a
gasoline
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic co ...
additive used to replace lead compounds for unleaded gasolines to improve the
octane rating
An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating ...
of low octane petroleum distillates. It reduces
engine knock
In spark ignition internal combustion engines, knocking (also knock, detonation, spark knock, pinging or pinking) occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignite ...
agent through the action of the
carbonyl groups. Fuels containing manganese tend to form manganese carbides, which damage
exhaust valve
A poppet valve (also called mushroom valve) is a valve typically used to control the timing and quantity of gas or vapor flow into an engine.
It consists of a hole or open-ended chamber, usually round or oval in cross-section, and a plug, usual ...
s. Compared to 1953, levels of manganese in air have dropped.
In tobacco smoke
The
tobacco plant
''Nicotiana'' () is a genus of herbaceous plants and shrubs in the family Solanaceae, that is indigenous to the Americas, Australia, Southwestern Africa and the South Pacific. Various ''Nicotiana'' species, commonly referred to as tobacco plants ...
readily absorbs and accumulates
heavy metals
upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead
Heavy metals are generally defined as ...
such as manganese from the surrounding soil into its leaves. These are subsequently inhaled during
tobacco smoking
Tobacco smoking is the practice of burning tobacco and ingesting the resulting smoke. The smoke may be inhaled, as is done with cigarettes, or simply released from the mouth, as is generally done with pipes and cigars. The practice is believed ...
. While manganese is a constituent of
tobacco smoke
Tobacco smoke is a sooty aerosol produced by the incomplete combustion of tobacco during the tobacco smoking, smoking of cigarettes and other tobacco products. Temperatures in burning cigarettes range from about 400 °C between puffs to abo ...
,
studies have largely concluded that concentrations are not hazardous for human health.
Role in neurological disorders
Manganism
Manganese overexposure is most frequently associated with
manganism
Manganism or manganese poisoning is a toxic condition resulting from chronic exposure to manganese. It was first identified in 1837 by James Couper.
Signs and symptoms
Chronic exposure to excessive manganese levels can lead to a variety of psyc ...
, a rare neurological disorder associated with excessive manganese ingestion or inhalation. Historically, persons employed in the production or processing of manganese alloys have been at risk for developing manganism; however, current health and safety regulations protect workers in developed nations.
The disorder was first described in 1837 by British academic John Couper, who studied two patients who were m.
Manganism is a biphasic disorder. In its early stages, an intoxicated person may experience depression, mood swings, compulsive behaviors, and psychosis. Early neurological symptoms give way to late-stage manganism, which resembles
Parkinson's disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
. Symptoms include weakness, monotone and slowed speech, an expressionless face, tremor, forward-leaning gait, inability to walk backwards without falling, rigidity, and general problems with dexterity, gait and balance.
Unlike
Parkinson's disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
, manganism is not associated with loss of the sense of smell and patients are typically unresponsive to treatment with
L-DOPA
-DOPA, also known as levodopa and -3,4-dihydroxyphenylalanine, is an amino acid that is made and used as part of the normal biology of some plants and animals, including humans. Humans, as well as a portion of the other animals that utilize -DOPA ...
. Symptoms of late-stage manganism become more severe over time even if the source of exposure is removed and brain manganese levels return to normal.
Chronic manganese exposure has been shown to produce a parkinsonism-like illness characterized by movement abnormalities.
This condition is not responsive to
typical therapies used in the treatment of PD, suggesting an alternative pathway than the typical
dopamine
Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic compound, organic chemical of the catecholamine and phenethylamine families. Dopamine const ...
rgic loss within the
substantia nigra
The substantia nigra (SN) is a basal ganglia structure located in the midbrain that plays an important role in reward and movement. ''Substantia nigra'' is Latin for "black substance", reflecting the fact that parts of the substantia nigra app ...
.
Manganese may accumulate in the
basal ganglia
The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an extern ...
, leading to the abnormal movements.
A mutation of the SLC30A10 gene, a manganese efflux transporter necessary for decreasing intracellular Mn, has been linked with the development of this Parkinsonism-like disease.
The
Lewy bodies
Lewy bodies are the inclusion bodies – abnormal aggregations of protein – that develop inside nerve cells affected by Parkinson's disease (PD), the Lewy body dementias ( Parkinson's disease dementia and dementia with Lewy bodies (DLB)), and ...
typical to PD are not seen in Mn-induced parkinsonism.
Animal experiments have given the opportunity to examine the consequences of manganese overexposure under controlled conditions. In (non-aggressive) rats, manganese induces mouse-killing behavior.
Childhood developmental disorders
Several recent studies attempt to examine the effects of chronic low-dose manganese overexposure on
child development
Child development involves the Human development (biology), biological, developmental psychology, psychological and emotional changes that occur in human beings between birth and the conclusion of adolescence. Childhood is divided into 3 stages o ...
. The earliest study was conducted in the Chinese province of Shanxi. Drinking water there had been contaminated through improper sewage irrigation and contained 240–350 μg Mn/L. Although Mn concentrations at or below 300 μg Mn/L were considered safe at the time of the study by the US EPA and 400 μg Mn/L by the
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
, the 92 children sampled (between 11 and 13 years of age) from this province displayed lower performance on tests of manual dexterity and rapidity, short-term memory, and visual identification, compared to children from an uncontaminated area. More recently, a study of 10-year-old children in Bangladesh showed a relationship between Mn concentration in well water and diminished IQ scores. A third study conducted in Quebec examined school children between the ages of 6 and 15 living in homes that received water from a well containing 610 μg Mn/L; controls lived in homes that received water from a 160 μg Mn/L well. Children in the experimental group showed increased hyperactive and oppositional behavior.
The current maximum safe concentration under EPA rules is 50 μg Mn/L.
Neurodegenerative diseases
A protein called
DMT1
Natural resistance-associated macrophage protein 2 (NRAMP 2), also known as divalent metal transporter 1 (DMT1) and divalent cation transporter 1 (DCT1), is a protein that in humans is encoded by the ''SLC11A2'' (solute carrier family 11, member 2) ...
is the major transporter in manganese absorption from the intestine, and may be the major transporter of manganese across the
blood–brain barrier
The blood–brain barrier (BBB) is a highly selective semipermeable membrane, semipermeable border of endothelium, endothelial cells that prevents solutes in the circulating blood from ''non-selectively'' crossing into the extracellular fluid of ...
. DMT1 also transports inhaled manganese across the nasal epithelium. The proposed mechanism for manganese toxicity is that dysregulation leads to oxidative stress, mitochondrial dysfunction, glutamate-mediated
excitotoxicity
In excitotoxicity, nerve cells suffer damage or death when the levels of otherwise necessary and safe neurotransmitters such as glutamate become pathologically high, resulting in excessive stimulation of receptors. For example, when glutamate re ...
, and aggregation of proteins.
See also
*
Manganese exporter, membrane transport protein
*
List of countries by manganese production
*
Parkerizing
Phosphate conversion coating is a chemical treatment applied to steel parts that creates a thin adhering layer of iron, zinc, or manganese phosphates, to achieve corrosion resistance, lubrication, or as a foundation for subsequent coatings or p ...
References
External links
National Pollutant Inventory – Manganese and compounds Fact SheetInternational Manganese InstituteNIOSH Manganese Topic Pageat ''
The Periodic Table of Videos
''Periodic Videos'' (also known as ''The Periodic Table of Videos'') is a video project and YouTube channel on chemistry. It consists of a series of videos about chemical elements and the periodic table, with additional videos on other topics i ...
'' (University of Nottingham)
All about Manganese Dendrites
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Chemical elements
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Chemical elements with body-centered cubic structure
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