Manganese

Manganese is a transition metal with the symbol Mn and atomic number 25. It plays a vital role in the human body, supporting bone growth, helping with the metabolism of nutrients, and protecting cells from damage caused by free radicals. Manganese is often found alongside iron and is vital to many proteins and enzymes.

1.0Introduction

Manganese is a solid metal with a crystal structure, positioned in Group 7 and Period 4 of the periodic table. As a d-block element, it is classified as a transition metal. The symbol Mn is derived from the Latin word magnes, meaning "magnet." Manganese is not a free element in nature; it commonly occurs in minerals such as pyrolusite (MnO₂).

Manganese is classified as a transition metal due to its unique electron structure, with one unpaired electron in a partially filled third orbital. It can exist in many oxidation states, including +7, +6, +4, +3, +2, and even -1, meaning its reactivity varies depending on the chemical process or molecule it’s in.

Additionally, manganese is paramagnetic, which means it is attracted to magnetic fields. It reacts with water oxygen, similar to iron rusts, causing it to oxidise.

2.0Physical Properties of Manganese 

3.0Chemical Properties of Manganese

1. Reaction with Oxygen: In the presence of oxygen, manganese burns to form tri-manganese tetraoxide:3Mn+2O₂​→Mn₃​O_4​ 
2. Reaction with Halogens: Manganese reacts readily with halogens, including chlorine, bromine, iodine, and fluorine:

• With chlorine:  Mn+Cl_2​→MnCl_2​
• With bromine: 2Mn+3Br_2​​→2MnBr_3​
• With iodine:    2Mn+3I_2​​→2MnI_3​
• With fluorine:  2Mn+3F_2​→2MnF₃

3. Reaction with Acids: Manganese dissolves quickly in acidic solutions, producing manganese(II) ions and releasing hydrogen gas:

Mn+2H⁺→Mn²⁺+H₂​

4. Reaction with Nitrogen: Manganese combines with nitrogen to form manganese nitride:

Mn+N→Mn₃N_2​

5. Reaction with Water: Manganese does not usually react with pure water, but it can rust in water that contains dissolved oxygen:

Mn +2H₂​O+O₂​→2MnO₂ ​+ 4H⁺

6. Oxidation States: Manganese exhibits multiple oxidation states, including +7, +6, +4, +3, +2, 0, and -1, depending on the chemical environment and reaction.

4.0Uses of Manganese

• Iron and Steel Production: Manganese is essential in the iron and steel industry, acting as a sulfur-fixing, deoxidising, and alloying agent.
• Manganese Steel: Manganese steel, with around 13% manganese content, is solid, making it ideal for applications such as railway tracks, rifle barrels, safes, and prison bars.
• Aluminium Alloys: Manganese is added to aluminium alloys to increase their strength and corrosion resistance.
• Batteries: Manganese is commonly used in batteries, especially as the cathode material in dry cell batteries.
• Pigment: Pigment is used as a pigment to colour glass and ceramics.
• Fungicide: Manganese sulfate is effective as a fungicide against various fungal diseases affecting crops.
• Catalyst in Chemical Processes: Manganese catalyses many chemical reactions, such as removing the green tint from glass caused by iron impurities.
• Nutritional Role: Manganese is vital for the body’s metabolism of amino acids, cholesterol, vitamins, and carbohydrates.
• Other Applications: Manganese is also used to dry black paints, reduce engine knocking, and produce oxygen, chlorine, and benzyl alcohol.