Manganese is a silvery-gray metal and is part of the group known as the transition metals. It is similar to iron. It is hard to melt, but easy to oxidize. Manganese forms chemical compounds in several oxidation states: +2, +4, and +7 are the most common. Manganese compounds can be black, brown, pink, red, green, blue, and purple. Manganese(II) compounds are pink or light brown. They are unreactive. Manganese(II) chloride is a common example. Manganese(III) compounds are weak oxidizing agents. Manganese(IV) compounds are stronger oxidizing agents, but they are rarer. They are normally black in colour. Manganese(IV) oxide is an example.
Manganese(V) compounds are not stable and disproportionate easily. They are bright blue. They are very rare. Hypomanganates are the most common manganese(V) compounds. Manganese(VI) compounds are made in the process used to make permanganates. They disproportionate too. Manganates are weak reducing agents and moderate oxidizing agents. They are bright green.
Manganese(VII) compounds are purple-black and are powerful oxidizing agents. Permanganates contain the MnO4- ion. They are normally purple-black and strong oxidizing agents. Potassium permanganate is an example.
Manganese is sometimes found alloyed with iron naturally. These rocks, called meteorites, came from space. Pyrolusite is one of the main sources of manganese. It also occurs as manganese carbonate. Some silicates have manganese in them.
Manganese is normally made in an alloy with steel. This is made by mixing manganese ore and iron ore in a furnace and reducing it with carbon. This forms an alloy called ferromanganese. Pure manganese is made by reacting the manganese ore with sulfuric acid and electrolyzing it.
Manganese is used a lot in steel to make it stronger. This is the main use for manganese metal. Manganese compounds, particularly manganese(IV) oxide, are used in alkaline cells and Leclanche cells. Manganese metal is also alloyed with aluminium.
Our bodies and plants need manganese to work right. If we do not get enough manganese, we can get sick. We get manganese from our food and vitamins also have some manganese to make sure that we get enough.
Manganese dust can irritate lungs. Some manganese compounds cause toxicity when ingested. Manganese is less toxic than nickel or copper. Permanganates are the most toxic manganese compounds. When someone is exposed to manganese for a long time it can cause a problem with the nervous system.
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