Manganese [Mn]


An: 25 N: 30
Am: 54.938049 g/mol
Group No: 7
Group Name: Transition metals
Block: d-block Period: 4
State: solid at 298 K
Colour: silvery metallic Classification: Metallic
Boiling Point: 2234K (2061oC)
Melting Point: 1519K (1246oC)
Density: 7.21g/cm3

Discovery Information

Who: Johann Gahn
When: 1774
Where: Sweden

Name Origin

Latin: mangnes (magnet); Ital. manganese. "Manganese" in different languages.


Most abundant ores are pyrolusite (MnO2), braunite (Mn2+Mn3+6SiO12), psilomelane [(BaH2O)2Mn5O10] and rhodochrosite (MnCO3). Manganese is mined in South Africa, Russia, Ukraine, Georgia, Gabon and Australia. Vast quantities of manganese exist in manganese nodules on the ocean floor. Attempts to find economically viable methods of harvesting manganese nodules were abandoned in the 1970s.
Psilomelane is one of the most abundant manganese ores.

Pyrolusite is one of the most abundant manganese ores.
Annual production is around 6.2 million tons.


Universe: 8 ppm (by weight)
Sun: 10 ppm (by weight)
Carbonaceous meteorite: 2800 ppm
Earth’s Crust: 1100 ppm
Seawater: Atlantic surface: 1 x 10-4 ppm; Atlantic deep: 9.6 x 10-5 ppm; Pacific surface: 1 x 10-4 ppm; Pacific deep: 4 x 10-5 ppm
Human: 200 ppb by weight; 23 ppb by atoms


Manganese is essential to iron and steel production, it also used in some aluminium alloys. It is also used in making; batteries, axles, rail switches, safes, ploughs and ceramics.
Manganese is used to decolourize glass (removing the greenish tinge that presence of iron produces) and, in higher concentration, make violet-coloured glass.
Potassium permanganate (KMnO4) is a potent oxidizer and used in chemistry and in medicine as a disinfectant.


The origin of the name manganese is complex. In ancient times, two black minerals from Magnesia in what is now modern Greece were both called magnes, but were thought to differ in gender. The male magnes attracted iron, and was the iron ore we now know as loadstone or magnetite, and which probably gave us the term magnet. The female magnes ore did not attract iron, but was used to decolourize glass. This feminine magnes was later called magnesia, known now in modern times as Pyrolusite (MnO2) or manganese dioxide. This mineral is never magnetic (although manganese itself is paramagnetic). In the 16th century, it was called manganesum by glassmakers, possibly as a corruption of two words since alchemists and glassmakers eventually had to differentiate a magnesia negra (the black ore) from magnesia alba (a white ore, also from Magnesia, also useful in glassmaking). Mercati called magnesia negra 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), which provided the name magnesium for that free element, when it was eventually isolated,much later.
Manganese compounds were in use in prehistoric times; paints that were pigmented with manganese dioxide can be traced back 17,000 years. The Egyptians and Romans used manganese compounds in glass-making, to either remove colour from glass or add colour to it. Manganese can be found in the iron ores used by the Spartans. Some speculate that the exceptional hardness of Spartan steels derives from the inadvertent production of an iron-manganese alloy.


More than 25 million tonnes of manganese ores are mined every year, representing 5 million tons of the metal, reserves of manganese are estimated to exceed 3 billion tonnes.



Manganese Compounds

Manganese(II) carbonate MnCO3
It is widely used as an additive to plant fertilizers to cure manganese deficient crops. It is also used in many health foods. It is also used in ceramics as a glaze colourant and flux.
Manganese(IV) oxide MnO2

Reactions of Manganese

Reactions with water
Manganese does not react with water under normal conditions
Reactions with air
3Mn(s) + 2O2(g) --> Mn3O4(s)
3Mn(s) + N2(g) --> Mn3N2(s)

Reactions with halogens
Manganese burns in chlorine to form manganese(II) chloride.
Mn(s) + Cl2(g) --> MnCl2(s)
Manganese burns in bromine to form manganese(II) bromide.
Mn(s) + Br2(g) --> MnBr2(s)
Manganese burns in iodine to form manganese(II) iodide.
Mn(s) + I2(g) --> MnI2(s)

The corresponding reaction between the metal and fluorine yields the manganese(II) fluoride and manganese(III) fluoride.
Mn(s) + F2(g) --> MnF2(s)
2Mn(s) + 3F2(g) --> 2MnF3(s)

Reactions with acids
Mn(s) + H2SO4(aq) --> Mn2+(aq) + SO42-(aq) + H2(g)

Occurrence of Manganese

Manganese occurs principally as Pyrolusite (MnO2), and to a lesser extent as rhodochrosite (MnCO3). Land-based resources are large but irregularly distributed; those of the United States are very low grade and have potentially high extraction costs. Over 80% of the known world manganese resources are found in South Africa and Ukraine. Other important manganese deposits are in China, Australia, Brazil, Gabon, India, and Mexico. US Import Sources (1998-2001): Manganese ore: Gabon, 70%; South Africa, 10%; Australia, 9%; Mexico, 5%; and other, 6%. Ferromanganese: South Africa, 47%; France, 22%; Mexico, 8%; Australia, 8%; and other, 15%. Manganese contained in all manganese imports: South Africa, 31%; Gabon, 21%; Australia, 13%; Mexico, 8%; and other, 27%.
Vast quantities of manganese exist in manganese nodules on the ocean floor. Attempts to find economically viable methods of harvesting manganese nodules were abandoned in the 1970s. Manganese is mined in Burkina Faso and Gabon.

Isotopes of Manganese

52Mn [27 neutrons]
Abundance: Synthetic
Half life: 5.591 days [ Electron Capture ]
Decay Energy: ? MeV
Decays to 52Cr.
Half life: 5.591 days [ beta+ ]
Decay Energy: 0.575 MeV
Decays to 52Cr.
Half life: 5.591 days [ Gamma Radiation ]
Decay Energy: 0.7, 0.9, 1.4 MeV
Decays to ?. 

53Mn [28 neutrons]
Abundance: Synthetic
Half life: 3.74 x 106 years [ Electron Capture ]
Decay Energy: ? MeV
Decays to 53Cr.
54Mn [29 neutrons]
Abundance: Synthetic
Half life: 312.3 days [ Electron Capture ]
Decay Energy: ? MeV
Decays to 54Cr.
Half life: 312.3 days [ Gamma Radiation ]
Decay Energy: 0.834 MeV
Decays to ?. 

55Mn [30 neutrons]
Abundance: 100%
Stable with 30 neutrons

0 Response to "Manganese [Mn]"

Post a Comment



CB Blogger