Name: Manganese
Symbol: Mn
Atomic number: 25
Atomic weight: 54.938045 (5)
Standard state: solid at 298 K
Group in periodic table: 7
Group name: Transition Metals
Period in periodic table: 4
Block in periodic table: d block
Color: silvery-grey metal
Classification: Metallic
Manganese, whose name is a derivation from the Greek word for magic, is a silvery-gray metal resembling iron. It is part of the iron group of elements, which are thought to be synthesized in large stars shortly before their supernova explosion. Manganese is hard and very brittle, difficult to fuse, but easy to oxidize.
According to John Emsley, author of Nature’s Building Blocks: A-Z Guide to the Elements, “Manganese makes up about 1000 ppm (0.1%) of the Earth's crust, making it the 12th most abundant element there Abundance of elements in the universe.” Sources of this commonly occurring element are thought to be the sun, meteorites, the Earth's crust, the oceans (manganese is present in quantity in the ocean’s floor), as well as rivers and streams.
The Linus Pauling Institute states that “Manganese is a required trace mineral for all known living organisms and may be essential for utilization of vitamin B. As such, it plays an important role in a number of physiologic processes; as a constituent of some enzymes and an activator of other enzymes. Low dietary manganese and low levels of manganese in blood or tissue have been associated with several chronic diseases such as: Osteoporosis, Diabetes mellitus and Epilepsy”. http://lpi.oregonstate.edu/infocenter/minerals/manganese/
The human body contains about 10 mg of manganese, which is stored mainly in the liver and kidneys; and it’s also an important component in the process of photosynthesis for plants.
Several oxides of manganese, for example manganese dioxide, are abundant in nature and due to color these oxides have been used as since the Stone Age. The cave paintings in Gargas contain manganese as pigments and these cave paintings are 30,000 to 24,000 years old.
Manganese compounds were used by Egyptian and Roman glassmakers, to either remove color from glass or add color to it.
Manganese is essential to iron and steel production, since by its virtue it makes iron and steel hard, but not brittle. Steelmaking, and iron making, have accounted for most 80-90% of the manganese demand. Manganese phosphating is used as a preventative treatment against rust and corrosion on steel. The second largest application for manganese is as an alloying agent for aluminum. Among a variety of other uses, manganese is a key component of low-cost stainless steel formulations. It is also used for its sulfur-fixing, deoxidizing, and alloying properties. Manganese ions have various colors, depending on their oxidation state, and are used industrially as pigments.
Manganese oxidizes easily and forms halides, oxides, sulfides, hydrides, and complexes. In the 20th century, manganese dioxide has been widely used in commercial applications as material for commercial disposable dry cells and dry batteries.
While, manganese compounds are less toxic than those of other widespread metals such as nickel and copper; in larger amounts, and apparently with far greater activity by inhalation, manganese can be toxic in mammals, including causing neurological damage which is sometimes irreversible. Excesses of Manganese build up in the Liver and Kidneys, the organs of elimination, and are difficult to remove from the body. Manganese poisoning has been linked to impaired motor skills and cognitive disorders and all manganese compounds should be regarded as highly toxic as well as possibly carcinogenic and teratogenic (causes birth defects).
According to Science Daily, “Manganism, or manganese poisoning, is prevalent in such occupations as mining, welding, and steel manufacturing. It is caused by exposure to excessive levels of the metal manganese, which attacks the central nervous system, producing motor and dementia symptoms that resemble Parkinson's disease.” http://www.sciencedaily.com/releases/2009/02/090201141559.htm
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