Manganese 25

Where is manganese used--or where does it impact our everyday lives?

Manganese
Symbol: Mn

Atomic number 25

Atomic mass: 54.94

Solid at room temperature
Melting point: 1246°C (2275 oF)

Boiling point: 2061 °C (3742 oF)

Density (at room temperature) 7.21 g/cm3

Hazards: Mn dusts and fumes Mn poisoning

Reactions with air:

With oxygen, Mn burns to form Mn3O4.
3Mn(s)+2O2(g)→ Mn3O4 (s)

With nitrogen reacts to form Mn3N2.
3Mn(s)+N2(g)→ Mn3N2(s)

Manganese is not reactive with water - or soluble

Main uses of the element: metallurgical alloys

When discovered: 1770 by Torbern Bergman inSweden

It is not found as a free element in nature; it is often found in combination with iron, and in many minerals
Electron configuration 2, 8, 8, 7 1s2, 2s2 2p6, 3s2 3p6, 3d5 4s2

Researcher: Antoine L.

LANL.gov

Senior IB Chemistry student Isaac S working on his Independent Assessment, IA, with manganese dioxide. A catalyst used in the decomposition of hydrogen peroxide--where it speeds up the reaction

WIS Photographer

Class of 2015 students in IB Chemistry investigating the dissolved oxygen content in Tregaron's pond and creek using the Winkler method which uses manganese sulfate to fix the dissolved oxygen in the water sample and then add acidified iodide to liberate iodine, which in turn is measured accurately with a sodium thiosulfate titration

I2 + 2Na2S2O3 --> 2NaI + Na2S4O6

SEE the video of students performing the Winkler method for dissolved oxygen.

Manganese is used in many alloys including ones used in aircraft airframes. The airframe of the aircraft in the photograph--a World-War II Vicker's Wellington bomber--is made of an aluminum alloy, duralumin (94% aluminum,Al, 4% copper, Cu, 1% magnesium, Mg, 1% manganese, Mn.) Chemistry teacher Mrs. H's father was on the restoration team for this Wellington R for Robert viewed at the Brooklands Museum, Weybridge, Uk.

WIS Photographer

Manganese, Mn, found in Spessartine, Mn3Al2(SiO4)3 found in Gilgit, Northern Areas, Pakistan on display at the National Museum of Natural History, Washington DC and viewed during a Chemistry One field trip. Manganese’s abundance in Earth's crust = 0.11%,

Photographer: Ela K.

Fairfieldite, Ca2MnFe(PO4)2.2H2O, from the Foote Mineral Co., Kings Mountain, North Carolina, USA viewed during a Chemistry One field trip to the National Museum of Natural History in Washington, DC, USA

Physics teacher, Mr. J, holding a presidential dollar coin which is a manganese alloy: 88.5% copper, Cu, 6% zinc, Zn, 3.5% manganese, Mn, and 2% nickel, Ni.

WIS Photographer

Look at a video of pouring manganese powder in the lab

Class of 2019, Antoine L, Lulu M, and Lily S, photographed these manganese minerals during a Chemistry One field trip to the Smithsonian National Museum of Natural History. The mineral is rhodochrosite, MnCO3 from

Red Cloud Mine, Arizona, USA

Sweet Home Mine, Alma, Colorado, USA

3 samples from Hotazel, Cape Province, South Africa

and Catamara, Argentina