MANGANESE





Manganese 3379
Photo by: Skv7774

Manganese

Overview

Manganese is a transition metal. The transition metals are the large block of elements in the middle of the periodic table. The periodic table is a chart that shows how chemical elements are related to each other. The transition metals make up Rows 4 through 7 in Groups 3 through 12 of the periodic table. Many of the best known and most widely used metals are in this group of elements.

It took chemists some time to discover the difference between manganese and iron. The two metals have very similar properties and often occur together in the Earth's crust. The first person to clearly identify the differences between the two elements was Swedish mineralogist Johann Gottlieb Gahn (1745-1818) in 1774.

SYMBOL
Mn

ATOMIC NUMBER
25

ATOMIC MASS
54.9380

FAMILY
Group 7 (VIIB)
Transition metal

PRONUNCIATION
MANG-guh-neez

Manganese plays an interesting role in the U.S. economy. It is absolutely essential in the production of iron and steel. No element has been found that can replace manganese is such applications. The United States has essentially no manganese supplies of its own, so it depends on imports from other nations.

Discovery and naming

One of the main ores of manganese is pyrolusite. Pyrolusite is made up primarily of the compound manganese dioxide (MnO 2 ). Early artists were familiar with pyrolusite. They used the mineral to give glass a beautiful purple color. They also used the mineral to remove color from a glass. When glass is made, it often contains impurities that give the glass an unwanted color. The presence of iron, for example, can give glass a yellowish tint. Adding pyrolusite to yellowish glass removes the color. The purple tint of pyrolusite balances out the yellow color of the glass. The glass ends up being clear and colorless.

By the mid-1700s, chemists began to suspect that pyrolusite might contain a new element. Some authorities credit German chemist Ignatius Gottfried Kaim with isolating the element in 1770. However, Kaim's report was not read by many chemists and was quickly lost.

During this period, some of the most famous chemists in Europe were trying to analyze pyrolusite, but none of them was successful. The problem was solved in 1774 when Gahn developed a method for removing the new element from pyrolusite. He heated pyrolusite with charcoal (pure carbon ). The carbon took oxygen away from manganese dioxide, leaving behind pure manganese:

The origin of manganese's name is a bit confusing. Early chemists associated the new element with a mineral called magnesia. That mineral got its name because it is magnetic. Magnesia does not contain manganese, but the name stuck.

Physical properties

Manganese is a steel-gray, hard, shiny, brittle metal. It is so brittle, in fact, that it cannot be machined in its pure form. Machining refers to the bending, cutting, and shaping of a metal by mechanical means. The melting point of manganese is 1,245°C (2,273°F) and its boiling point is about 2,100°C (3,800°F). Its density is 7.47 grams per cubic centimeter.

Manganese exists in four allotropic forms. Allotropes are forms of an element with different physical and chemical properties. The element changes from one form to another as the temperature rises. The form that exists from room temperature up to about 700°C (1,300°F) is the most common form.

Chemical properties

Manganese is a moderately active metal. It combines slowly with oxygen in the air to form manganese dioxide (MnO 2 ). At higher temperatures, it reacts more rapidly. It may even burn, giving off a bright white light. Manganese reacts slowly with cold water, but more rapidly with hot water or steam. It dissolves in most acids with the release of hydrogen gas. It also combines with fluorine and chloride to make manganese difluoride (MnF 2 ) and manganese dichloride (MnCl 2 ).

Occurrence in nature

Manganese never occurs as a pure element in nature. It always combines with oxygen or other elements. The most common ores of manganese are pyrolusite, manganite, psilomelane, and rhodochrosite. Manganese is also found mixed with iron ores. The largest producers of manganese ore in the world are China, South Africa, the Ukraine, Brazil, Australia, Gabon, and Kazakstan.

Manganese also occurs abundantly on the ocean floor in the form of nodules. These nodules are fairly large lumps of metallic ores. They usually contain cobalt, nickel, copper, and iron, as well as manganese. Scientists estimate that up to 1.5 trillion metric tons of manganese nodules may lie on the floors of the world's oceans and large lakes. Currently, there is no profitable method for removing these ores.

Manganese is the 12th most abundant element in the Earth's crust. Its abundance is estimated to be 0.085 to 0.10 percent. That makes it about as abundant as fluorine or phosphorus.

Up to 1.5 trillion metric tons of manganese nodules (large lumps of metallic ores) may lie on ocean floors.

Isotopes

Only one naturally occurring isotope of manganese exists, manganese-22. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope.

Men and machine lay railroad tracks. A common alloy of manganese, ferromanganese, is contained in the steel used to produce railroad tracks.
Men and machine lay railroad tracks. A common alloy of manganese, ferromanganese, is contained in the steel used to produce railroad tracks.

Nine radioactive isotopes of manganese are known also. A radioactive isotope is one that breaks apart and gives off some form of radiation. Radioactive isotopes are produced when very small particles are fired at atoms. These particles stick in the atoms and make them radioactive.

None of the radioactive isotopes of manganese has any important commercial uses.

Extraction

The usual method for producing pure manganese is to heat manganese dioxide (MnO 2 ) with carbon or aluminum. These elements remove the oxygen and leave pure metal:

Uses

Up to 90 percent of all manganese produced is made into steel alloys. An alloy is made by melting and mixing two or more metals. The mixture has properties different from those of the individual metals. The addition of manganese to steel makes the final product hard, as well as resistant to corrosion (rusting) and mechanical shock.

The heavy steel found in bank vaults contains ferromanganese, a manganese alloy.
The heavy steel found in bank vaults contains ferromanganese, a manganese alloy.

The most common alloy of manganese is ferromanganese. This alloy contains about 48 percent manganese combined with iron and carbon. Ferromanganese is the starting material for making a very large variety of steel products, including tools, heavy-duty machinery, railroad tracks, bank vaults, construction components, and automotive parts. About 60 percent of the manganese used in the United States in 1996 went to the manufacture of ferromanganese.

Another common alloy of manganese is silicomanganese. It contains manganese, silicon, and carbon in addition to iron. It is used for structural components and in springs. The production of silicomanganese accounted for about 33 percent of the manganese used in the United States in 1996.

Manganese is also used to make alloys with metals other than iron or steel. For example, the alloy known as manganin is 84 percent copper, 12 percent manganese, and 4 percent nickel. Manganin is used in electrical instruments.

Compounds

Less than 10 percent of all the manganese used in the United States goes to the production of manganese compounds. Perhaps the most important commercial use of these compounds is manganese dioxide (MnO 2 ). Manganese dioxide is used to make dry-cell batteries. These batteries are used in electronic equipment, flashlights, and pagers. Dry cell batteries hold a black pasty substance containing manganese dioxide. The use of manganese dioxide in a dry cell prevents hydrogen gas from collecting in the battery as electricity is produced.

Another manganese compound, manganous chloride (MnCl 2 ), is an additive in animal food for cows, horses, goats, and other domestic animals. Fertilizers also contain manganous chloride so that plants get all the manganese they need.

Finally, small amounts of manganese compounds are used as coloring agents in bricks, textiles, paints, inks, glass, and ceramics. Manganese compounds can be found in shades of pink, rose, red, yellow, green, purple, and brown.

Health effects

Manganese is one of the chemical elements that has both positive and negative effects on living organisms. A very small amount of the element is needed to maintain good health in plants and animals. The manganese is used by enzymes in an organism. An enzyme is a molecule that makes chemical reactions occur more quickly in cells. Enzymes are necessary to keep any cell operating properly. If manganese is missing from the diet, enzymes do not operate efficiently. Cells begin to die, and the organism becomes ill.

Fortunately, the amount of manganese needed by organisms is very small. It is not necessary to take extra manganese to meet the needs of cells.

Manganous chloride (MnCl 2 ) is an additive in animal food.

In fact, an excess of manganese can create health problems. These problems include weakness, sleepiness, tiredness, emotional disturbances, and even paralysis. The only way to receive such a large dose is in a factory or mine. Workers may inhale manganese dust in the air.



User Contributions:

Jennifer
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Aug 28, 2008 @ 6:18 pm
there's lots of useful informations on this article.
collin
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Dec 15, 2008 @ 6:18 pm
thanks for this article i needed it for a project!!
Lynn
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Jan 18, 2009 @ 10:22 pm
Wow, thanks so much! That really helped with my projuect
Christie
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Jan 19, 2009 @ 6:18 pm
very easy to understand information, written to be understood by normal people!!
Janae
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Jan 22, 2009 @ 7:19 pm
Thanks! I'm doing a project for school and I was looking for information like that!!
Lisa
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Feb 7, 2009 @ 12:00 am
thanks. this site helped much. when was this site last updated? oh well. ta.
Misha
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Apr 12, 2009 @ 11:11 am
This site is AMAZING i thought my project was going to take hours here it took less than 20 minutes!!!! Thank You!!! :)
Chalse
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May 6, 2009 @ 3:15 pm
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(:
mike
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Oct 19, 2009 @ 1:13 pm
best site ever thx alot!!! helped me out got me an a on my assignment
Galen Monroe
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Oct 28, 2009 @ 5:17 pm
Thank you. I am planning an alloy in a Casting at University. This was extremely helpful and informative.
Meagan
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Nov 2, 2009 @ 12:12 pm
wow ,,
thanks that helped so much for my science project :)
kaitlyn
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Nov 18, 2009 @ 5:17 pm
Thanks,this helped so much with my physical science project!
Evalina
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Nov 28, 2009 @ 10:22 pm
wow this really helped me for my science project
and i agree with Misha because i thought my project would take forever but it only took 30 minutes :)
violet
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Dec 7, 2009 @ 10:22 pm
this was very helpful. but i want to know who's the author?
Susan
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Dec 16, 2009 @ 2:14 pm
What would be the best maganese element to build for a science project
Rocky
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Dec 16, 2009 @ 5:17 pm
THIS WAS A GOOD WEBSITE BUT NOT MANY COOL FACTS. THAT WAS WHAT I WAS LOOKING FOR
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Mar 3, 2010 @ 11:23 pm
Thnks a bunch. . .im here doing my report for school and this site made it really easy for me to understand and it had all the info. i need.!
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Mar 11, 2010 @ 9:21 pm
USEFUL INFORMATION FOR CHEMISTRY PROJECT AND EXAM. THANKS A LOT
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Mar 25, 2010 @ 6:18 pm
thank soo much i had to look up 40 elements for school and this was the best website!
the berger
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May 9, 2010 @ 3:15 pm
This really helped for my science project!!!:) My project didn't take long at all.
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Aug 25, 2010 @ 1:13 pm
Thanks,
I had no idea that this went into dry cell production. Now I wonder why we didn't recycle batteries earlier. Are they recyclable or is the hydrogen gas somehow permanent?
Of course, this explains why we don't have a new national freight rail.
Elizabeth
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Sep 16, 2010 @ 7:19 pm
Thanks for the info... I couldn't seem to find where to buy Manganese though... Oh well, this will help with my paper. My entire grade had to pick an element to do a report over of around 500 to 1000 words, and, as you can see, I picked/ended up with Manganese... even though I have an unknown magnet with Krypton on it... which is extremely off topic. Thanks for the information!
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Feb 13, 2011 @ 3:15 pm
Thank you so much! this was really really helpful for my science project and made it much easier than i thought the project would be
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Apr 5, 2011 @ 6:06 am
this information is so use full and currently working on a mine project in Kenya and by
just having such information is a great thing and am going to make good use of it please
make more on this artical also on Iron Rock, and also Copper Plates we so much appreciate.


Great work keep it coming.

Eng: Edwin M Kumba
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Apr 18, 2011 @ 8:08 am
thanks but wat is mangenese made of? thx for the info by the way.
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Apr 19, 2011 @ 9:09 am
thanks i needed this info for my paper in chemistry because i couldnt find any of this anywhere and this site was a savior :)
tap
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Jun 18, 2011 @ 8:08 am
This site is awesome wtih a lot of information and contributes a lot towards studies.
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Jul 30, 2011 @ 4:04 am
Thanks, its very good information.I am working on the effect of manganese on steel properties.
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Oct 12, 2011 @ 10:22 pm
:] Thank you!!! Thank you so much, whoever did this, lol. This gave me alot of info for my element project, :)
Mack
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Nov 12, 2011 @ 9:21 pm
Thanks a bunch! It helped with many issues. Again, thanks.
Ambermarie Ellis
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Nov 15, 2011 @ 12:12 pm
Thank you sooo much!!! :) You have really helped me with my science project. I found all of the answers that I needed. Again thank you so much. :)
saiful kassim
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Jan 10, 2012 @ 5:05 am
nice info. by the way i would like to know about Mn which includes it biochemistry toward human,like it biological role,meabolism,clinical application?will you provide it?
vikas gupta
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Jan 16, 2012 @ 12:00 am
nice imformation & easy to understand. but i want to know how much percent of mangnese is suitable in carbon steel. what are bad effects of using more mangnese.
Brooke Leonard
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Mar 6, 2012 @ 9:21 pm
A TON OF INFO! COULDNT HAVE ASKED FOR A BETTER SITE TO COME ACROSS! THANKS! OMG SO USEFUL
Joey And Sara
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Apr 10, 2012 @ 2:14 pm
Thank you so much for the imformation it helped so much. We had to do it for our project and without all the imformation you guys gave us we would have probaly failed. Actually we havent turned it in but when we do we will propbably pass.
Wesley
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May 23, 2012 @ 12:12 pm
thanks for the help you helped me a lot with my science project
Lizzy
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Sep 26, 2012 @ 4:16 pm
I think there was a lot of good information. I would've like to have known more uses besides mostly alloys. :(
alexa
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Nov 9, 2012 @ 5:17 pm
this helped me so much on my 4 page single spaced chem report! thank you!
Zephry
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Dec 19, 2012 @ 9:21 pm
this helped me a lot on my science report i even got an A+ on it
Jenna
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Jan 1, 2013 @ 3:15 pm
Oh, my gosh. Thanks for all the great info! This helped a lot for my science project I had to do over winter break! I never thought it would be this easy to find such useful information! Once again, thank you.
Andy
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Jan 4, 2013 @ 10:10 am
Thank you for all of this! It really helped. My science teacher likes us to get information that dose not waste his time. He can be so picky. Once again, thank you this helped alot thank you much. :)
Grace
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Jan 29, 2013 @ 9:21 pm
You rock. You helped me with a school project
Thank you for the good help
I had trouble and you helped me
Lily
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Mar 15, 2013 @ 2:02 am
OMG!!! Awesome site!!! THANK YOU!!! This will help me a lot on my project! :)
Kathy
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Apr 18, 2013 @ 10:10 am
WOW! Thank you very much for this info. :) I doing an element project for Chem and this site has ALL the info that I need i appreciate it God Bless. ^_^
1Dwuvr
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May 16, 2013 @ 8:20 pm
They actually do use manganese as a medicine. You can get a deficiency and doctors will prescribe a small dose of it. There is research that suggests it might improve symptoms of PMS, anemia, and osteoarthritis. Given, it is a very small dose.
aComment
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Sep 30, 2013 @ 8:20 pm
This is the best article I have seen! Thank, DopeFreshNation :^)
Mahal
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Oct 7, 2013 @ 12:12 pm
This article was very informative and gave me almost all the info needed for my project.
farrin
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Oct 27, 2013 @ 7:19 pm
thanks for this great information!!! it helped me on my project. thanks again!!!
hiiiiii
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May 14, 2014 @ 6:18 pm
does it say how they find manganese before they dig it up?

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