Zinc carbonate is an inorganic compound with the chemical formula ZnCO3ZnCO3. It is also known as zinc monocarbonate. Smithsonite (which is also known as turkey fat or zinc spar) is the naturally occurring mineral of zinc carbonate. Zinc carbonate appears as a white crystalline solid that contains zinc (Zn2+)(Zn2+) and carbonate (CO2–3)(CO32–) ions. This article focuses on discussing the basics related to zinc carbonate. There will be a discussion on the preparation, properties and uses of zinc carbonate.

Zinc Carbonate: Chemical Formula

The chemical formula of zinc carbonate is \({\rm{ZnC}}{{\rm{O}}_{\rm{3}}}\). It is a salt that contains zinc \(\left( {{\rm{Z}}{{\rm{n}}^{2 + }}} \right)\) and carbonate \(\left( {{\rm{CO}}_3^{2 – }} \right)\) ions. Since an ionic bond exists between the zinc and carbonate ions, it is considered as an ionic compound.

Zinc carbonate can be represented as:

or

In zinc carbonate, zinc is octahedral, and each carbonate is bonded to six zinc centres such that the oxygen atoms are three-coordinate. Zinc carbonate adopts a structure similar to that of calcium carbonate.

The molar mass of zinc carbonate is approximately equal to \(125.4\;{\rm{g}}/{\rm{mol}}\).

Zinc Carbonate Chemical Formula Derivation

The chemical formula of zinc carbonate can be derived using the criss-cross method.

Using this, the chemical formula of zinc carbonate can be written as:

Zinc carbonate contains zinc \(\left( {{\rm{Z}}{{\rm{n}}^{2 + }}} \right)\) and carbonate \(\left( {{\rm{CO}}_3^{2 – }} \right)\) radicals.  The valency of zinc radical is two and that of carbonate radical is also two. By criss-crossing these valency numbers, the chemical formula of zinc carbonate is \({\rm{ZnC}}{{\rm{O}}_{\rm{3}}}\). That is,

Zinc Carbonate: Preparation

 Zinc carbonate can be prepared using the following methods:

1. Naturally, zinc carbonate \(({\rm{ZnC}}{{\rm{O}}_{\rm{3}}})\) can be obtained as smithsonite.
2. Zinc carbonate can be produced in the laboratory by treating the cold solution of zinc sulphate with potassium bicarbonate.
3. Zinc carbonate is also produced when potassium carbonate reacts with zinc nitrate. The chemical equation for the reaction can be given as,
   \({{\rm{K}}_2}{\rm{C}}{{\rm{O}}_3} + {\rm{Zn}}{\left( {{\rm{N}}{{\rm{O}}_3}} \right)_2} \to {\rm{ZnC}}{{\rm{O}}_3} + 2{\rm{KN}}{{\rm{O}}_3}\)
4. Zinc carbonate is also precipitated from zinc sulphate solution by the addition of sodium bicarbonate or sodium carbonate to it. The chemical equations for such reactions can be given as,
   By the addition of sodium carbonate to zinc sulphate solution:
   \({\rm{ZnS}}{{\rm{O}}_4}({\rm{aq}}) + {\rm{N}}{{\rm{a}}_2}{\rm{C}}{{\rm{O}}_3}({\rm{aq}}) \to {\rm{N}}{{\rm{a}}_2}{\rm{S}}{{\rm{O}}_4}({\rm{aq}}) + {\rm{ZnC}}{{\rm{O}}_3}\left( {\rm{s}} \right)\)
   By the addition of sodium bicarbonate to zinc sulphate solution:
   \({\rm{ZnS}}{{\rm{O}}_4}({\rm{aq}}) + 2{\rm{NaHC}}{{\rm{O}}_3}({\rm{aq}}) \to {\rm{N}}{{\rm{a}}_2}{\rm{S}}{{\rm{O}}_4}({\rm{aq}}) + {\rm{ZnC}}{{\rm{O}}_3}({\rm{s}}) + {{\rm{H}}_2}{\rm{O}} + {\rm{C}}{{\rm{O}}_2}\)

Zinc Carbonate: Properties

Let us discuss the physical and chemical properties of zinc carbonate.

Zinc Carbonate: Physical Properties

1. Zinc carbonate appears as a white crystalline solid. It is an odourless compound.
2. It is insoluble in water, pyridine, acetone, alcohol, and ammonia.
3. Zinc carbonate is soluble in dilute acids and alkalis.
4. The density of zinc carbonate is approximately equal to \(4.4\;{\rm{g}}/{\rm{c}}{{\rm{m}}^3}\).

Zinc Carbonate: Chemical Properties

1. Decomposition of Zinc Carbonate: 

Zinc carbonate, on heating at higher temperatures, decomposes to form zinc oxide and carbon dioxide. The chemical equation for the reaction can be given as,

2. Reactions of Zinc Carbonate:

Reaction of Zinc Carbonate with Hydrochloric Acid

Zinc carbonate reacts with hydrochloric acid to form zinc chloride and water along with the liberation of carbon dioxide gas. The chemical equation for the reaction can be given as,

\({\rm{ZnC}}{{\rm{O}}_3} + 2{\rm{HCl}} \to {\rm{ZnC}}{{\rm{l}}_2} + {\rm{C}}{{\rm{O}}_2} + {{\rm{H}}_2}{\rm{O}}\)

Reaction of Zinc Carbonate with Nitric Acid

Zinc carbonate reacts with nitric acid to form zinc nitrate and water along with the release of carbon dioxide gas. The chemical equation for the reaction can be given as,

\({\rm{ZnC}}{{\rm{O}}_3} + 2{\rm{HN}}{{\rm{O}}_3} \to {\rm{Zn}}{\left( {{\rm{N}}{{\rm{O}}_3}} \right)_2} + {\rm{C}}{{\rm{O}}_2} + {{\rm{H}}_2}{\rm{O}}\)

Reaction of Zinc Carbonate with Sulphuric Acid

Zinc carbonate reacts with sulphuric acid to form zinc sulphate and water along with the liberation of carbon dioxide gas. The chemical equation for the reaction can be given as,

\({\rm{ZnC}}{{\rm{O}}_3} + {{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4} \to {\rm{C}}{{\rm{O}}_2} + {{\rm{H}}_2}{\rm{O}} + {\rm{ZnS}}{{\rm{O}}_4}\)

Zinc Carbonate: Uses

Zinc carbonate has got several uses. They include:

1. It is used in the manufacture of porcelain, pottery, and rubber.
2. Zinc carbonate is used as a pigment.
3. It is used as an antiseptic (An antimicrobial substance used to prevent the growth of disease-causing microorganisms) and astringents (They are the water-based skincare products used to remove excess oil from the skin, tighten pores, and remove leftover makeup).
4. Zinc carbonate is used for the extraction of zinc metal from the ore.
5. It is also used to prevent zinc deficiency diseases.
6. Zinc carbonate is used as a feed additive.
7. Smithsonite, the naturally occurring mineral of zinc carbonate has several uses in the field of metallurgy, electronics, and construction.
8. Zinc carbonate is used in toothpaste to recover dentin in teeth.
9. Zinc carbonate is sometimes used as a micronutrient to prevent disease in animals.
10. Zinc carbonate can be used for the preparation of other zinc compounds.

Frequently Asked Questions on Zinc Carbonate

Frequently asked questions related to zinc czrbonate are listed as follows:

Q. What is the formula of zinc carbonate?
Ans: Zinc carbonate is an inorganic compound with the chemical formula \({\rm{ZnC}}{{\rm{O}}_3}\). It is naturally found as smithsonite.

Q. How do you write the chemical formula of zinc carbonate?
Ans: The chemical formula of zinc carbonate can be written using the criss-cross method. Zinc carbonate contains zinc \(({\rm{Z}}{{\rm{n}}^{2 + }})\) and carbonate \(({\rm{C}}{{\rm{O}}_3}^{2 – })\) radicals.  The valency of zinc radical is two and that of carbonate radical is also two. By criss-crossing these valency numbers, the chemical formula of zinc carbonate is \({\rm{ZnC}}{{\rm{O}}_3}\).

Q. What is the use of zinc carbonate?
Ans: Zinc carbonate has got several uses. They include:
1. It is used in the manufacture of porcelain, pottery, and rubber.
2. Zinc carbonate is used as a pigment.
3. Zinc carbonate is used for the extraction of zinc metal from the ore.
4. It is also used to prevent zinc deficiency diseases.
5. Zinc carbonate is used as a feed additive.

Q. Is zinc carbonate good for the skin?
Ans: Zinc carbonate is widely used in certain cosmetics. However, exposure to zinc carbonate directly can cause irritation to the skin and eyes.

Q. What does ZnCO₃ decompose into?
Ans: Zinc carbonate decomposes to form zinc oxide and carbon dioxide on heating at higher temperatures. The chemical equation for the reaction can be given as,