Manganese


Manganese is a chemical element represented by the symbol Mn. It is discovered by the Swedish scientist Johann Gahn. The word manganese is derived from the latin word magnes which means magnet. Since it is alloyed with metals like aluminium, antimony, and copper which gives the end product as magnet. Naturally occurring manganese is composed of one stable isotope. In the Earth, manganese is found in a number of minerals of different chemical and physical properties, but is never found as a free metal in nature. The most important mineral is pyrolusite, because it is the main ore mineral for manganese. Manganese is a reactive element which readily reacts with ions in water and air. Trace amounts of manganese are very important to good health. It makes bones strong yet flexible, and it aids the body in absorbing Vitamin B1. It also is an important activator for the body to use enzymes. As little as 0.00002% Mn in the human body is essential. Studies have shown that lack of manganese leads to infertility in animals.

Occurences and Geological deposits
Manganese makes up about 1000 ppm (0.1%) of the Earth's crust, making it the 12th most abundant element there. Soil contains 7–9000 ppm of manganese with an average of 440 ppm. Seawater has only 10 ppm manganese and the atmosphere contains 0.01 µg/m3.Manganese occurs principally as pyrolusite (MnO2), braunite, (Mn2+Mn3+6)(SiO12), psilomelane (Ba,H2O)2Mn5O10, and to a lesser extent as rhodochrosite (MnCO3).
About 80% of the manganese deposits are found in the region of South Africa and Ukraine and the remaining are found in parts of Australia, India, China, Brazil, Ghana, and Kazakhstan.

Properties
·Manganese has steel or silvery grey in color.
·It has isometric crystal system.
·Manganese is metallic in its luster.
·Its specific gravity is 7.44.
·It is opaque in nature.

Applications/ Uses
1.Manganese has useful in steel and iron production for sulphur fixing, deoxidising and alloying properties.
2.Steel becomes harder when it is alloyed with manganese.
3.Manganese dioxide is used to manufacture ferroalloys, manufacture dry cell batteries, to decolorize glass and to prepare some chemicals, like oxygen and chlorine.
4.Manganese metal is used as a brick and ceramic colorant, in copper and aluminum alloys, and as a chemical oxidizer and catalyst.
5.Potassium permanganate (KMnO4) is used as a bactericide and algicide in water and wastewater treatment, and as an oxidant in organic chemical synthesis.

Question and Answers
1.Which is the important ore of manganese?
Ans. Pyrolusite.

2.What quantity of manganese is present in earths crust?
Ans.1000 ppm i.e 0.1% of the earths crust.

3.Mention some properties of manganese?
Ans. Manganese has steel or silvery grey in color.
It has isometric crystal system.
Manganese is metallic in its luster.
4.Write few applications of manganese?
Ans.Manganese has useful in steel and iron production for sulphur fixing, deoxidising and alloying properties.
Manganese dioxide is used to manufacture ferroalloys, manufacture dry cell batteries, to decolorize glass and to prepare some chemicals, like oxygen and chlorine.

References:
www.wikipedia.com
www.mineralzone.com


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