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Manganese is a chemical element; it has symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in in combination with iron. Manganese was first isolated in the 1770s. It is a transition metal with a multifaceted array of industrial alloy uses, particularly in . 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 defense systems. It is a critical component in dozens of and . It is found mostly in the bones, but also the liver, kidneys, and brain. In the human brain, the manganese is bound to manganese , most notably glutamine synthetase in .
Manganese is commonly found in laboratories in the form of the deep violet salt potassium permanganate where it is used as an Oxidizing agent. Potassium permanganate is also used as a biocide in water treatment.
It occurs at the in some enzymes. (2025). 9789400755604, Springer. ISBN 9789400755604 Electronic-book . Of particular interest is the use of a Mn–O atom cluster, the oxygen-evolving complex, in the production of oxygen by plants.
Manganese is part of the iron group of elements, which are thought to be synthesized in large shortly before the supernova explosion. 53Mn decays to 53Cr with a half-life of 3.7 million years. Because of its short half-life, 53Mn is relatively rare; it is produced by the impact of cosmic rays on iron. Manganese isotopic contents are typically combined with chromium isotopic contents and have found application in isotope geology and radiometric dating. Mn–Cr isotopic ratios reinforce the evidence from 26Al and 107Pd for the early history of the Solar System. Variations in 53Cr/52Cr and Mn/Cr ratios from several 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 nucleosynthesis processes immediately before the coalescence of the Solar System.
Alpha manganese (α-Mn) is the equilibrium phase at room temperature. It has a body-centered cubic lattice and is unusual among elemental metals in that it has a very complex unit cell, with 58 atoms per cell (29 atoms per primitive unit cell) with manganese atoms in four different types of surroundings (sites). It is paramagnetic at room temperature and antiferromagnetic at temperatures below .
Beta manganese (β-Mn) forms when heated above the transition temperature of . It has a primitive cubic structure with 20 atoms per unit cell at two types of sites, which is as complex as that of any other elemental metal. It is easily obtained as a metastable phase at room temperature by rapid quenching of manganese at in ice water. It does not show Magnetism, remaining paramagnetic down to the lowest temperature measured (1.1 K).
Gamma manganese (γ-Mn) forms when heated above . It has a simple face-centered cubic structure (four atoms per unit cell). When quenched to room temperature it converts to β-Mn, but it can be stabilized at room temperature by alloying it with at least 5 percent of other elements (such as C, Fe, Ni, Cu, Pd or Au). These solute-stabilized alloys distort into a face-centered tetragonal structure.
Delta manganese (δ-Mn) forms when heated above and is stable up to the manganese melting point of . It has a body-centered cubic structure (two atoms per cubic unit cell).
Aside from various permanganate salts, Mn(VII) is represented by the unstable, volatile derivative Mn2O7. (MnO3F and MnO3Cl) are powerful oxidation. The most prominent example of Mn in the +6 oxidation state is the green anion manganate, MnO42−. Manganate salts are intermediates in the extraction of manganese from its ores. Compounds with oxidation states +5 are somewhat elusive, and often found associated to an oxide (O2−) or nitride (N3−) ligand. One example is the blue anion hypomanganate MnO43−.
Mn(IV) is somewhat enigmatic because it is common in nature but far rarer in synthetic chemistry. The most common Mn ore, pyrolusite, is MnO2. It is the dark brown pigment of many and is also a common ingredient in dry cell batteries. Complexes of Mn(IV), such as in K2MnF6, are known but are rarer than those of manganese in the lower oxidation states. Mn(IV)-OH complexes are an intermediate in some , including the oxygen-evolving center (OEC) in plants.
Simple derivatives of Mn3+ are rarely encountered but can be stabilized by suitably alkaline ligands. Manganese(III) acetate is an oxidant useful in organic synthesis. Solid compounds of manganese(III) are characterized by a strong purple-red color and a preference for distorted octahedral coordination resulting from the Jahn-Teller effect.
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 derived from manganese(II) sulfate (MnSO4) and manganese(II) chloride (MnCl2). This oxidation state is also seen in the mineral rhodochrosite (manganese(II) carbonate). Manganese(II) commonly exists with a high-spin ground state, with 5 unpaired electrons, because of its high pairing energy. There are no spin-allowed d–d transitions in manganese(II), which explain its faint color. (2025). 9780716746201, Macmillan. ISBN 9780716746201.
| Mn(1,5-COD)22− | |
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| Common oxidation states are in bold. | |
Of greatest commercial interest is methylcyclopentadienyl manganese tricarbonyl (MMT), which is used as an anti-knock compound added to gasoline in some countries, featuring Mn(I). Consistent with other aspects of Mn(II) chemistry, manganocene () is high-spin. In contrast, its neighboring metal, iron, forms an air-stable, low-spin derivative in the form of ferrocene (). When conducted under an atmosphere of carbon monoxide, reduction of Mn(II) salts gives dimanganese decacarbonyl , 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 and are derived from .
In Mn(CH3)2(dmpe)2, Mn(II) is low spin, which contrasts with the high spin character of its precursor, MnBr2(dmpe)2 (dmpe = (CH3)2PCH2CH2P(CH3)2). PolyAlkyl group and polyAryl group derivatives of manganese often exist in higher oxidation states, reflecting the electron-releasing properties of alkyl and aryl ligands. One example is Mn(CH3)62−.
Manganese dioxide, 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 MnO2 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 until modern times and is evident in 14th-century glass from Venice.
Because it was used in glassmaking, manganese dioxide was available for experiments by alchemists, the first chemists. Ignatius Gottfried Kaim (1770) and Johann Glauber (17th century) discovered that manganese dioxide could be converted to permanganate, a useful laboratory reagent. By the mid-18th century, the Swedish chemist Carl Wilhelm Scheele used manganese dioxide to produce chlorine. First, hydrochloric acid, or a mixture of dilute sulfuric acid and sodium chloride was made to react with manganese dioxide, and later hydrochloric acid from the Leblanc process was used and the manganese dioxide was recycled by the Weldon process. (2025). 9783527306732 ISBN 9783527306732
Scheele and others were aware that pyrolusite (mineral form of manganese dioxide) contained a new element. Johan Gottlieb Gahn isolated an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon. Ignatius Gottfried Kaim also may have reduced manganese dioxide to isolate the metal, but that is uncertain.
The manganese content of some iron ores used in Greece led to speculations that steel produced from that ore contains additional manganese, making the 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. 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 in 1866 and the subsequent improvement of batteries containing manganese dioxide as cathodic depolarizer increased the demand for manganese dioxide. Until the development of batteries with nickel–cadmium and lithium, most batteries contained manganese. The zinc–carbon battery and the alkaline battery normally use industrially produced manganese dioxide because naturally occurring manganese dioxide contains impurities. In the 20th century, manganese dioxide was widely used as the cathode for commercial disposable dry batteries of both the standard (zinc–carbon) and alkaline types.
Manganese is essential to iron and steelmaking by virtue of its sulfur-fixing, deoxidized steel, and alloying properties. This application was first recognized by the British metallurgist Robert Forester Mushet (1811–1891), who introduced the element to the steel manufacture process in 1856 in the form of spiegeleisen.
| Manganese ore | Psilomelane (manganese ore) | Spiegeleisen is an iron alloy with a manganese content of approximately 15%. | Manganese oxide dendrites on limestone from Solnhofen, Germany – a kind of pseudofossil. Scale is in mm | Mineral rhodochrosite (manganese(II) carbonate) |
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. 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 and Brazil.
Manganese is mainly mined in South Africa, Australia, China, Gabon, Brazil, India, Kazakhstan, Ghana, Ukraine and Malaysia. In South Africa, most identified deposits are located near Hotazel in the Northern Cape Province, (Kalahari manganese fields), with a 2011 estimate of 15 billion tons. In 2011 South Africa produced 3.4 million tons, topping all other nations.
In 1972, the CIA's Project Azorian, through billionaire Howard Hughes, commissioned the ship Hughes Glomar Explorer with the cover story of harvesting manganese nodules from the sea floor. This cover story triggered a rush of activity to collect manganese nodules. The real mission of Hughes Glomar Explorer was to raise a sunken Soviet submarine, the K-129, with the goal of retrieving Soviet code books.
Manganese also occurs in the oceanic environment, as dissolved manganese (dMn), which 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.
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., Cr3+, Cu2+, Zn2+, and Pb2+). 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 Mn2+ (e.g., Cr3+ to Cr(VI) and colorless hydroquinone to tea-colored quinone polymers).
A more progressive extraction process involves directly reducing (a low grade) manganese ore by heap leaching. This is done by Percolation 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 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 and ferrous iron (Fe2+) in a 1.6:1 ratio. The iron reacts with the manganese dioxide (MnO2) to form iron hydroxide (FeO(OH)) and elemental manganese (Mn).
This process yields greater than 90% recovery of the manganese. For further purification, the manganese can then be sent to an electrowinning facility.
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 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 of up to 863 MPa. Steel with 12% manganese was discovered in 1882 by Robert Hadfield and is still known as mangalloy. It was used for British military Brodie helmet and later by the U.S. military.
The same material also functions in newer Alkaline battery (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.
Manganese(IV) oxide (manganese dioxide, MnO2) is used as a reagent in organic chemistry for the oxidation of benzylic alcohols (where the hydroxyl group is adjacent to an aromatic ring). (2025). 9780470842898 ISBN 9780470842898 Manganese dioxide has been used since antiquity to oxidize and neutralize the greenish tinge in glass from trace amounts of iron contamination. MnO2 is also used in the manufacture of oxygen and chlorine and in drying black paints. In some preparations, it is a brown pigment for paint and is a constituent of natural umber.
Tetravalence manganese is used as an activator in red-emitting . While many compounds are known which show luminescence, the majority are not used in commercial application due to low efficiency or deep red emission. However, several Mn4+ activated fluorides were reported as potential red-emitting phosphors for warm-white LEDs. But to this day, only K2SiF6:Mn4+ is commercially available for use in warm-white .
The metal is occasionally used in coins; until 2000, the only United States coin to use manganese was the 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 and the Presidential $1 coins, are made from a brass containing 7% of manganese with a pure copper core.
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) 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, Mas Subramanian and associates at Oregon State University discovered that manganese can be combined with yttrium and indium to form an intensely blue, non-toxic, inert, fade-resistant pigment, YInMn Blue, the first new blue pigment discovered in 200 years.
The oxygen-evolving complex (OEC), containing four atoms of manganese, is a part of photosystem II contained in the thylakoid membranes of chloroplasts. The OEC is responsible for the terminal Oxygen evolution during the light reactions of photosynthesis, i.e., it is the catalyst that makes the O2 produced by plants.
| +Current AIs of Mn by age group and sex !colspan="2" | Males !colspan="2" | Females | |
| 1–3 | 1.2 | 1–3 | 1.2 |
| 4–8 | 1.5 | 4–8 | 1.5 |
| 9–13 | 1.9 | 9–13 | 1.6 |
| 14–18 | 2.2 | 14–18 | 1.6 |
| 19+ | 2.3 | 19+ | 1.8 |
| pregnant: 2 | |||
| lactating: 2.6 |
The European Food Safety Authority (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 are defined the same as in the United States. For people ages 15 and older, the AI is set at 3.0 mg/day. AIs for pregnancy and lactation are 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.
Excessive exposure or intake may lead to a condition known as manganism, a neurodegenerative disorder that causes neuronal death and symptoms similar to Parkinson's disease. (2025). 9789400774995, Springer. ISBN 9789400774995
Mn levels can increase in seawater 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 and their functionality, such as phagocytosis and activation of Prophenoloxidase, 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.
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. 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, manganism is not associated with loss of the sense of smell and patients are typically unresponsive to treatment with L-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 to the typical loss within the substantia nigra. Manganese may accumulate in the basal ganglia, 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 body 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.
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