Element - Manganese (Mn)

Manganese is one of the chemical elements. The element manganese belongs to the “d” block of the periodic table. Manganese belongs to group number 7 and period number 4. The atomic number of manganese is 25.

Occurrence of manganese

Manganese is one of the naturally occurring chemical elements. This element is found in trace amounts in the environment. Among the most abundant element present in the earth’s crust, manganese is the 5th one. It is commonly found in rocks, food, soil, and water. However, manganese is not available in its pure form. It is usually available in combination with other substances such as oxides, silicates, and carbonates.

The minerals of manganese are widely distributed in nature. Rhodochrosite (manganese carbonate) and pyrolusite (manganese dioxide) are the most commonly found minerals of manganese. China, Gabon, Australia, and Africa are the primary areas for manganese mining.

Manganese nodules contain about 24% manganese along with other elements in trace amounts. They are usually seen on ocean floors.

Properties of manganese

The physical properties of manganese are as follows.

The electronic configuration of Manganese is [Ar] 3d⁵4s²
The oxidation states of Manganese are 7, 6, 4, 3, 2, 0, and -1.
It has an atomic mass of 54.938 g.mol -1.
The colour of manganese is usually pinkish to grey.
At 20°C, it exists in the solid-state.
Manganese is generally brittle and hard.
Pure manganese reacts easily.
Manganese is hard to melt. Its melting point is 1246°C.
The boiling point of manganese is 2061°C.
It has a density of 7 g cm−3.
In presence of air, manganese tarnishes.
In presence of heat, it gets oxidized.
Manganese gets diluted in acids easily.
In presence of water, it forms rust similar to iron.
The most common isotope of manganese is the ⁵⁵Mn. The atomic mass of ⁵⁵Mn is 54.938 g.mol -1 with 100% natural abundance.
The first ionization energy of manganese is 716 kJ.mol -1 whereas the second ionization energy is 1489 kJ.mol -1.
The electronegativity of manganese is 1.5.

Chemical reactions of manganese

Free manganese is very much reactive. Therefore, it exists in combination with other substances such as oxides, carbonates, and silicates. Pure manganese can be obtained from its oxide MnO2 either electrolytically or chemically. It has 7 oxidates states - 7, 6, 4, 3, 2, 0, and -1. Hence, it is seen with a wide range of other chemical elements.

Here are a few important chemical reactions of manganese.

1. Burning of manganese

In the presence of oxygen, pure manganese burns to form tri manganese tetraoxide.

3Mn(s)+2O₂(g)→Mn₃O₄(s)(1)

2. Dilution of manganese

Manganese dilutes in acidic solutions very easily.

3. The reaction of manganese with nitrogen

Manganese reacts with nitrogen to form

3Mn(s)+N₂(g)→Mn₃N₂(s)

4. The reaction of manganese with water

Manganese generally does not react with water under normal conditions.

5. The reaction of manganese with halogens

Manganese readily reacts with halogens such as chlorine, bromine, iodine, and fluorine. Compared to all halogens, it is highly reactive with chlorine.

The reaction of manganese with halogens is represented below.

Mn(s)+Cl₂(g)→MnCl₂(s)(3)

Mn(s)+Br₂(g)→MnBr₂(s)(4)

Mn(s)+I₂(g)→MnI₂(s)

Uses of manganese

The uses of manganese in our day-to-day life are as follows.

Manganese is widely used in the production of iron and steel.
Manganese is a critical part of economical stainless steel and many broadly utilized aluminium alloys.
Manganese dioxide is additionally utilized as a catalyzing agent.
Manganese is additionally utilized to decolourize glass and make violet-shaded glass.
Potassium permanganate is a powerful oxidizer and is utilized as a sanitiser.
The other significant manganese-containing compounds are manganese carbonate and manganese oxide. Manganese carbonate is used as a starting material for many other chemical compounds. Manganese oxide is widely used in ceramics and the preparation of fertilizers.
Manganese oxide is used in the quantitative analysis of various chemical compounds.
Manganese steel is used for prison bars, railway tracks, and rifle barrels.
Manganese forms magnetic alloys when combined with antimony, copper, and aluminium.
Manganese oxide (oxidation state is 4) is also used as a rubber additive.

The biological significance of manganese

Manganese is an essential component in most living organisms. The average amount of manganese present in humans is 12mg. Manganese is a vital component of bones, enzymes, ligaments, and other connective tissues. Manganese deficiency makes bones less flexible and may lead to frequent bone fractures. On the other hand, manganese is crucial for Vitamin B1 utilization.