{"id":98,"date":"2020-04-08T15:03:51","date_gmt":"2020-04-08T15:03:51","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=98"},"modified":"2023-08-16T09:28:54","modified_gmt":"2023-08-16T09:28:54","slug":"manganese","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/manganese\/","title":{"rendered":"Manganese (Mn)"},"content":{"rendered":"\n

Manganese is a chemical element with the atomic number 25 in the periodic table. It\u2019s the fifth most abundant metal that occurs in Earth\u2019s crust. A member of the transition metals family of elements, manganese has four allotropic forms which make it an extremely versatile element. Its most stable oxidation states are +2, +6, and +7. This chemical is mostly obtained from the manganese dioxide (MnO2) compound, i.e. the mineral ore labeled as <\/span>pyrolusite<\/span><\/i>.\u00a0<\/span><\/p>\n\n\n\n

Manganese participates in the highly significant photosynthesis of the plants, which produces the oxygen<\/a> we breathe in the atmosphere. As a trace element, this mineral also takes part in the enzyme processes in humans and animals. Additionally, it plays a significant role in the development of bones and the regulation of cellular mechanisms and metabolic processes.<\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Manganese<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>Mn<\/td><\/tr>
Name<\/td>Manganese<\/td><\/tr>
Atomic Number<\/td>25<\/td><\/tr>
Atomic Weight<\/td>54.938 g.mol-1<\/td><\/tr>
Group<\/td>7 (Transition metal)<\/td><\/tr>
Period<\/td>4 (d-block)<\/td><\/tr>
Color<\/td>A silvery-gray metal with a purple hue<\/td><\/tr>
Physical State<\/td>Solid at room temperature<\/td><\/tr>
Half-life<\/td>From less than 105 nanoseconds to 3.7 million years<\/td><\/tr>
Electronegativity<\/td>1.5<\/td><\/tr>
Density<\/td>7.3 g.cm-3 at 20\u00b0C<\/td><\/tr>
Melting Point<\/td>1246\u00b0C, 2275\u00b0F, 1519 K<\/td><\/tr>
Boiling Point<\/td>2061\u00b0C, 3742\u00b0F, 2334 K<\/td><\/tr>
Van der Waals Radius<\/td>0.126 nm<\/td><\/tr>
Ionic Radius<\/td>0.08 nm (+2) ; 0.046 nm (+7)<\/td><\/tr>
Isotopes<\/td>25<\/td><\/tr>
Most Characteristic Isotope<\/td>55Mn<\/td><\/tr>
Electronic Shell<\/td>[Ar] 3d\u20754s\u00b2<\/td><\/tr>
The Energy of the First Ionization<\/td>716 kJ.mol-1<\/td><\/tr>
The Energy of the Second Ionization<\/td>1489 kJ.mol-1<\/td><\/tr>
Discovery Date<\/td>1774<\/td><\/tr>
Discovered By<\/td>Carl Wilhelm Scheele and Johan Gottlieb Gahn<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
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With the periodic table symbol Mn, atomic number 25, atomic mass of 54.938 g.mol<\/span>-1<\/span>, and electron configuration [Ar] 3d<\/span>5<\/span>4s<\/span>2<\/span>, manganese is a very brittle and hard silvery-gray metal. It reaches its boiling point at 2061\u00b0C, 3742\u00b0F, 2334 K, while the melting point is achieved at 1246\u00b0C, 2275\u00b0F, 1519 K. <\/span><\/p>\n\n\n\n

This member of the transition metals family of elements in the periodic table has an electronegativity of 1.5 according to Pauling, whereas the atomic radius according to van der Waals is 0.126 nm. <\/span><\/p>\n\n\n\n

Manganese occurs in four allotropic forms. Among them, the alpha phase(\u03c3) is the most stable form of element 25. This complex cubic structure of Mn exists from room temperature to -725\u00b0C. The Beta(\u03b2) form of manganese occurs between 725 -1095\u00b0C. The tetragonal gamma (\u03b3) form of this chemical element forms in temperature between 1095-1135\u00b0C, while the delta (\u2206) form of manganese exists only above the temperature of 1134 -1245\u00b0C. <\/span><\/p>\n\n\n\n

Both the chemical and physical properties of manganese resemble the respective properties of iron<\/a>, except manganese metal is harder and more brittle as a substance than iron. Also, the metal form of manganese is susceptible to corrosion when exposed to moist air, while it oxidizes superficially when the air is dry. Manganese in oxidation state +7 is powerfully oxidizing, and similarly to titanium<\/a>, vanadium<\/a>, and chromium<\/a>, it corresponds to the total number of 3d and 4s electrons.<\/span><\/p>\n\n\n\n

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How Was Manganese Discovered?<\/span><\/h2>\n\n\n\n

Even since ancient times, the black ore pyrolusite (manganese dioxide, MnO<\/span>2<\/span>) was familiar to the people. The evidence for this claim originates from around 30,000 years ago when the prehistoric <\/span>cave painters of the Lascaux region<\/span><\/a> of France have been using black manganese dioxide to express their thoughts by drawing on the rock walls of the caves. <\/span><\/p>\n\n\n\n

In ancient Rome and Egypt, the glass-blowers were using this mineral to produce <\/span>clear and transparent glass<\/span><\/a>, removing the green hue by adding some minerals containing manganese(IV) oxide to the mixture.\u00a0<\/span><\/p>\n\n\n\n

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The Serendipitous Finding of Johann Heinrich Pott (1692 – 1777)<\/span><\/h3>\n\n\n\n

Surely, the ancient civilization did not know about manganese oxide. This substance was not recognized as a chemical until 1740 when the German chemist Johann Heinrich Pott observed a new earth metal in the composition of the pyrolusite mineral. Namely, he tried to investigate the existence of iron in the compound. <\/span><\/p>\n\n\n\n

By exposing a fusion of caustic potash (potassium<\/a> hydroxide) with pyrolusite to air, this professor of chemistry in the Collegium medicochirurgicum in Berlin, Germany, managed to produce one of the strongest oxidizing agents – potassium permanganate (KMnO<\/span>4<\/span>), nowadays widely used in medicine. <\/span><\/p>\n\n\n\n

The result of Pott\u2019s experiment which showed no iron in the compound triggered further interest in the new substance in his fellow chemists, but no one was able to isolate the pure metal form of manganese from the pyrolusite.<\/span><\/p>\n\n\n\n

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The Successful Discovery of Carl Wilhelm Scheele and Johan Gottlieb Gahn<\/span><\/h3>\n\n\n\n

In 1774, the discoverer of both chlorine<\/a>, molybdenum<\/a>, barium<\/a>, and oxygen, Carl Wilhelm Scheele (1742 – 1786) teamed with his Swedish colleague Johan Gottlieb Gahn (1745 – 1818) to use all their experience for successful isolation of the new dark-colored element from the mineral ore. <\/span><\/p>\n\n\n\n

By using charcoal as the reducing agent exposed to an increased temperature, these two chemists eventually achieved their revolutionary goal. The result of their chemical trial was a white, hard, and brittle manganese metal, recognized as a new chemical element.\u00a0\u00a0<\/span><\/p>\n\n\n\n

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How Did Manganese Get Its Name?<\/span><\/h2>\n\n\n\n

The first mineral ores that have been found in the region of Magnesia, Greece, contained both magnesium<\/a> and manganese. They were commonly known under the name <\/span>magnesia<\/span><\/i>. In the 1600s, the magnesium minerals were distinguished with the name  \u201c<\/span>magnesia alba\u201d<\/span><\/i> (or <\/span>white magnesia<\/span><\/i>), while the dark manganese oxides were given the name \u201c<\/span>magnesia nigra\u201d<\/span><\/i> (or black magnesia). <\/span><\/p>\n\n\n\n

The presently used name of the element comes from the Latin word <\/span>“magnes”<\/span><\/i>, which means <\/span>magnet<\/span><\/i>. Even though manganese does not possess any magnetic qualities in its pure elemental form, the element got this name after its compounds which have been used in glass-making. These compounds were called \u201c<\/span>magnes<\/span><\/i>\u201d in Latin.\u00a0<\/span><\/p>\n\n\n\n

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Where Can You Find Manganese?<\/span><\/h2>\n\n\n\n

This chemical element is widely distributed in Earth\u2019s crust. It\u2019s so common that it can be found almost everywhere on our Planet – in every plant, animal, or human being; in the soil or the ocean waters. It\u2019s one of the iron groups of elements that are believed to have been produced by supernova explosions of the aged stars in the Universe. <\/span><\/p>\n\n\n\n

It typically occurs as a part of the mineral ores and the minerals pyrolusite (alpha-manganese dioxide (MnO<\/span>2<\/span>)), romanechite, bixbyite, manganite, rhodochrosite (manganese carbonate), rhodonite, and wad. Gabon, South Africa, Australia, and Brazil are the locations of the biggest manganese ore mines in the world. <\/span><\/p>\n\n\n\n

Manganese also occurs in the hard, ovoid, or spherically formed compact masses of matter that have been created by the precipitation of mineral cement on the ocean floor. <\/span><\/p>\n\n\n\n

These manganese-rich concretions are also referred to as <\/span>polymetallic nodules<\/span><\/i>, because they contain other metals in their composition, such as iron, silicon<\/a>, and aluminum. It\u2019s estimated that there are larger quantities of manganese in these ocean nodules than in the mineral ores. <\/span><\/p>\n\n\n\n

This substance is produced by the electrolysis process directly from the ore, but it can also be synthetically prepared by decomposition of manganous nitrate or by electrolysis of an aqueous solution of manganese sulfate.\u00a0<\/span><\/p>\n\n\n\n

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Manganese in Everyday Life<\/span><\/h2>\n\n\n\n

This chemical element has a wide application in almost all spheres of our living, especially in the steel industry and medicine:<\/span><\/p>\n\n\n\n