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Manganese (Mn)

QUICK REFERENCE

  • Symbol: Mn
  • Atomic Number: 25
  • Atomic Weight: 54.938044
  • Element Classification: Transition Metal
  • Discovered By: Johan Gottlieb Gahn
  • Discovery Date: 1774
  • Name Origin: From the Latin ‘magnes’, meaning magnet; derived from Magnesia, a region in Greece
  • Density(g/cc): 7.44
  • Melting Point: 1246°C
  • Boiling Point: 2061°C
  • Appearance: Silvery metallic
  • Atomic Radius(pm): 127

Discovery

Manganese was recognized as an element by the Swedish chemist Johan Gottlieb Gahn in 1774, though compounds containing manganese, such as pyrolusite, were used by ancient civilizations thousands of years prior. Gahn was able to isolate manganese by reducing the dioxide (pyrolusite) with carbon. The recognition of manganese as a distinct element helped to further understand its role in steelmaking and various chemical processes.

Relation to Other Elements

Manganese is a transition metal, placed in group 7 of the periodic table, between chromium and iron. It shares many properties with these neighboring transition metals, including the formation of various oxidation states, ranging from -3 to +7, which is more varied than most transition metals. This versatility in oxidation states allows manganese to form a wide range of compounds with different properties. Manganese is most commonly found in nature in its +2 oxidation state, which is a pale pink color in aqueous solutions.

Natural Occurrence

Manganese is the 12th most abundant element in the Earth’s crust and is found in many minerals, with pyrolusite (manganese dioxide) being the most significant ore. It is also found in nodules on the ocean floor and in iron ores, from which it is often extracted as a byproduct. Manganese is essential to iron and steel production and is also important in plant and animal life, serving as a necessary trace element for various biological processes.

Uses

Manganese has numerous industrial and biological applications:

  • Steel Production: The most significant use of manganese is in steel production, where it is added to improve strength, toughness, and wear resistance. Manganese steel, containing around 13% manganese, is exceptionally resistant to wear and is used in railway tracks, safes, and prison bars.
  • Aluminum Alloys: Manganese is added to aluminum alloys to improve their strength and corrosion resistance.
  • Chemical Industry: Various manganese compounds are used in fertilizers, pigments (such as manganese dioxide for brown coloring), batteries (like disposable alkaline and zinc-carbon batteries), and as catalysts in chemical reactions.
  • Biological Role: Manganese is essential for the functioning of many enzymes in living organisms, playing a critical role in photosynthesis in plants and in the metabolism of amino acids, cholesterol, and carbohydrates in animals.

The discovery of manganese significantly impacted the development of durable materials and the chemical industry, highlighting the importance of this versatile element in modern technology and biological systems.

 

Chromium (Cr)

Iron (Fe)