Manganese (II) chloride Formula – Structure, Properties, Uses, Sample Questions

Manganese (Mn) is a chemical compound with atomic number 25 in the periodic table. It is a mineral found in several foods like nuts, and seeds while grains, tea, and green leafy vegetables. It is a silvery-white metal with hard, brittle. Chlorine (Cl) is a greenish-yellow gas with atomic number 17 in the periodic table. It has a pungent odor-like smell. This gas is harmful to nature, it is 2-5 times denser than air. It is the 2nd lightest halogen among all the elements. It has two isotopes, that are stable.

Manganese (II) Chloride

Manganese(II) chloride is an inorganic compound, it is a dichloride salt of manganese. It is an important nutrient and is used as food for many plants and animals origin. Let’s learn more about Manganese (II) chloride by understanding its formula, structure, properties,

Formula Manganese (II) Chloride

The Chemical formula of  Manganese (II) Chloride is,

• In anhydrous form: MnCl₂.
• In Dihydrate Form: MnCl₂·2H₂O.
• In Tetrahydrate Form: MnCl₂·4H₂O.

Structure of Manganese (II) chloride

It has anhydrous, dihydrate, and tetrahydrate forms.

Anhydrous form

Tetrahydrate form

Preparation of Manganese (II) Chloride

Manganese chloride’s preparation is usually done in the laboratory,

• Manganese metal when treated with HCl acid, we get Manganese (II) Chloride in tetrahydrate form.

Mn + 2HCl + 4H₂O → MnCl₂(H₂O)₄ + H₂.

• When Manganese (II) Carbonate is treated with HCl acid, we get Manganese (II) Chloride in tetrahydrate form.                      

MnCO₃ + 2HCl + H₂O → MnCl₂(H₂O)₄ + CO₂.

• When Manganese(IV) oxide is treated with concentrated acid like HCl we get, manganese (II) chloride.

MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂.

Physical Properties of Manganese (II) Chloride

• The molar weight of Manganese (II) Chloride is 125.844 g/mol in anhydrous form,161.874 g/mol in dihydrate form, and 197.91 g/mol in tetrahydrate form.
• The Density of Manganese (II) Chloride is  2.977 g/cm³ (anhydrous), 2.27 g/cm³ (dihydrate) and2.01 g/cm³ (tetrahydrate).
• The Melting point of Manganese (II) Chloride is  654 °C (anhydrous), 135 °C (dihydrate) and 58 °C (tetrahydrate).
• The Boiling point of Manganese (II) Chloride is  1,225 °C.
• It is a pink solid in its tetrahydrate form.
• It is soluble in water and slightly soluble in ethanol and insoluble in ether.

Chemical Properties of Manganese (II) Chloride

• Manganese (II) Chloride dissolves in water, it gives mildly acidic solutions with a pH of 4. Acids solutions contain the metal aquo complex [Mn(H₂O)₆]₂+. It’s a weak Lewis acid. 

MnCl₂(aq) + K₂CO₃(aq) → MnCO₃(s) + 2 KCl. 

In these equations, “MnCl₂(aq)” refers to [Mn(H₂O)₆]²⁺, which is the principal form of manganese in aqueous solutions of any manganese chloride.

• It reacts with chloride ions to get a series of solids containing the subsequent ions [MnCl₃]−, [MnCl4]^2-, and [MnCl₆]^4-. 
• It reacts with typical organic ligands, it undergoes oxidation by air to allow Mn(III) complexes, like [Mn(CN)₆]^3-, and [Mn(acetylacetonate)3].

MnCl₂ + 2Ph₃P → [MnCl₂(Ph₃P)₂]. MnCl₂ + 2 NaC₅H₅→ Mn(C₅H₅)₂ +    2NaCl.

Uses of Manganese(II) chloride

• It is used in the assembly of Leclanche cell batteries.
• Aqueous solutions of these are used in P-NMR. 
• It is also used to determine the dimensions.
• Manganese chloride is paramagnetic, this is used when MnCl₂ is used as a contrast agent in MRI scanning.

Sample Questions

Question 1: Is Manganese(II) Chloride soluble in water?

Answer:

Manganese Chloride is soluble in water. Manganese source for uses compatible with chlorides. Hydrate or anhydrous forms may be purchased.

Question 2: Is Manganese (II) chloride ionic or covalent?

Answer: 

It is an inorganic compound in which manganese(II) is coordinated to 2 chloride ions. In its state manganese(II) chloride may be a polymeric solid. And it adopts a layered cadmium chloride-like structure.

Question 3: What are the hazards of Manganese (II) Chloride?

Answer: 

It may Causes eye burns, severe eye damage. It is Non-combustible. Thermal decomposition can lead to release of irritating gases and vapours. May be harmful if inhaled. May cause respiratory tract irritation, may cause skin irritation. It’s poisoning, can be caused by long-term exposure to manganese dust or fumes.

Question 5: How is Manganese (II) Chloride prepared?

Answer:

When manganese metal is reacted with acid like HCl we get MnCl₂.

Mn + 2HCl → MnCl₂ + H₂.

Question 6: What are the uses of Manganese (II) Chloride?

Answer:

1. It is used in the assembly of Leclanche cell batteries.
2. Aqueous solutions of these  are used in P-NMR. 
3. It is also used to determine the dimensions.
4. It is paramagnetic, this is used when MnCl₂ is used as a contrast agent in MRI scanning.

Question 7: What is the oxidation number of Manganese (II) Chloride?

Answer:

The oxidation number of MnCl₂ is +2, there are 2 chlorine atoms in MnCl₂. So the total oxidation number of Manganese (II) chloride will be 2.