Understanding Zinc Carbonate: Formula, Physical Properties, and Real-Life Uses
Zinc carbonate is a white crystalline powder also known as smithsonite or calamine or zinc spar. It was named after the scientist (english) James Smithson. It is an ore of zinc, the zinc Carbonate formula is ZnCO3. Earlier smithsonite was confused with hemimorphite before it was realized that both of them were two different minerals. Both the minerals have similar appearance and the term calamine is used for both of them, which led to this confusion. It is a white and odorless crystalline solid, sub-micron, or nano-powder and is insoluble in water, alcohol, or acetone but is only slightly soluble in ammonia. It is soluble in alkalis and acids. Zinc carbonate is an important source of zinc because it can be easily converted to other zinc compounds such as zinc oxide. The process can be achieved by heating which results in the formation of zinc oxide and carbon dioxide. This process is also known as calcination.
Let's discuss more about Zinc Carbonate Structure, Its physical and chemical properties.
Zinc Carbonate Structure
Given below is the structure of Zinc carbonate:
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Physical Properties of Zinc Carbonate
The molecular weight of Zinc carbonate is 125.38 g/mol.
The Boiling Point of Zinc carbonate is 333.6 °C.
The Melting Point of Zinc carbonate is 1970 °C.
The Density of Zinc carbonate is 3.5 g/cm3.
It is a white powder and has a faint vinegar odor.
It is basic in nature so the pH level is above 10.
It is insoluble in water.
Chemical Properties of Zinc Carbonate
Zinc carbonate reacts with acids to form zinc chloride and releases carbon dioxide gas.
ZnCO3 + HCl → ZnCl2 + CO2
ZnCO3 + H2SO4 → ZnSO4 + CO2 + H2O
Zinc carbonate while going for decomposition reaction forms zinc oxide and releases carbon dioxide gas.
ZnCO3 → ZnO + CO2
Hydrothermal synthesis of zinc carbonate is a result of the reaction between ZnCl2 and K2CO3.
ZnCl2 (aq) + K2CO3 (aq) → ZnCO3 (s) + 2KCl (aq)
Uses of Zinc Carbonate
It is an inorganic salt and is commonly used as a catalyst in organic synthesis reactions.
It is an appropriate precursor for the fabrication of zinc oxide particles.
It is extensively used in rubber production as a raw material. It is added to improve the translucency or transparency of the natural rubber material as these two materials have a very comparative refractive index.
Due to its fungicide and antiseptic properties. It is used in a wide range of products such as bath, make-up, personal cleanliness, shaving, oral care, and skin & hair care products.
It is also used in animal feed additives. Lack of zinc carbonate can restrict the animal’s growth because it has an important contribution for the development of bone.
zinc carbonate is also used in the petroleum industry as a Sulphur absorber.
It is used in dusting upon inflamed surfaces as an astringent and absorbent.
Due to its antiseptic properties it is frequently used in pharmaceuticals.
Conclusion
Zinc carbonate is an ore of zinc and is an essential material in many applications. Demand for zinc carbonate is increasing because its application areas such as cosmetics, agriculture, or rubber production are growing at a rapid rate. Depending on its application, production scale, or structure there are different synthesis routes uses of zinc carbonate. Zinc nano-powder can be extensively used in areas like rubber production, respiratory systems, or cosmetics. The size of the powder greatly affects the performance of the material. Lastly, the use of zinc carbonate seems to increase in the future due to the growing cosmetic, rubber, and agriculture industries.
FAQs on Zinc Carbonate: Properties, Structure, and Applications
1. What is the chemical formula and molar mass of zinc carbonate?
The chemical formula for zinc carbonate is ZnCO₃. Its molar mass is calculated by adding the atomic masses of its constituent atoms: zinc (65.38 g/mol), carbon (12.01 g/mol), and three oxygen atoms (3 x 16.00 g/mol). This results in a molar mass of approximately 125.39 g/mol.
2. What are the key physical and chemical properties of zinc carbonate (ZnCO₃)?
Zinc carbonate (ZnCO₃) exhibits several distinct properties:
Appearance: It is a white, crystalline solid or powder and is odourless.
Solubility: It is practically insoluble in water and alcohol but soluble in dilute acids and alkalis.
Density: It has a density of about 4.398 g/cm³.
Decomposition: Upon strong heating, it undergoes thermal decomposition (calcination) to form zinc oxide (ZnO) and carbon dioxide (CO₂).
Natural Occurrence: It occurs naturally as the mineral smithsonite, also known as calamine.
3. What are the main applications of zinc carbonate in various industries?
Zinc carbonate has several important industrial and commercial applications:
Metallurgy: It serves as a primary source of zinc. The ore is heated (calcined) to produce zinc oxide, which is then reduced to obtain zinc metal.
Cosmetics and Skincare: As an astringent and skin protectant, it is used in lotions and ointments, similar to calamine.
Pigments: It is used in the manufacturing of paints and ceramics as a white pigment.
Rubber Industry: It acts as a curing agent and accelerator in the vulcanization of rubber.
Chemical Manufacturing: It is a precursor for producing other zinc salts and compounds.
4. What happens when zinc carbonate is heated? Explain the calcination process.
When zinc carbonate is heated strongly, it undergoes a chemical change called thermal decomposition or calcination. In this process, the compound breaks down into zinc oxide (ZnO) and carbon dioxide gas (CO₂). Zinc oxide is a yellow solid when hot and turns white upon cooling. This reaction is a crucial step in the extraction of zinc from its ore (smithsonite). The balanced chemical equation for the reaction is:
ZnCO₃(s) → ZnO(s) + CO₂(g)
5. What does the crystal structure of zinc carbonate look like?
Zinc carbonate, in its mineral form smithsonite, adopts a trigonal crystal structure, which is similar to that of calcite (calcium carbonate). In this lattice structure, each zinc ion (Zn²⁺) is coordinated to six oxygen atoms from different carbonate ions (CO₃²⁻), and each carbonate ion is linked to surrounding zinc ions. This arrangement forms a stable, three-dimensional network, contributing to its insolubility and crystalline nature.
6. Why is zinc carbonate insoluble in water but readily dissolves in acids?
Zinc carbonate is insoluble in water due to its high lattice energy, which means a significant amount of energy is required to break the ionic bonds between the Zn²⁺ and CO₃²⁻ ions in its crystal structure. However, it dissolves in acids because the carbonate ion (CO₃²⁻) is the anion of a weak acid (carbonic acid, H₂CO₃). When an acid is added, the hydrogen ions (H⁺) react with the carbonate ions to form unstable carbonic acid, which quickly decomposes into water (H₂O) and carbon dioxide (CO₂) gas. This consumption of carbonate ions shifts the equilibrium, causing the solid zinc carbonate to dissolve.
7. How is zinc carbonate different from zinc oxide?
Zinc carbonate (ZnCO₃) and zinc oxide (ZnO) are both important zinc compounds but differ significantly:
Composition: Zinc carbonate contains zinc, carbon, and oxygen, while zinc oxide only contains zinc and oxygen.
Chemical Formula: The formula is ZnCO₃ for zinc carbonate and ZnO for zinc oxide.
Thermal Stability: Zinc carbonate is thermally unstable and decomposes upon heating to form zinc oxide. Zinc oxide itself is highly stable at high temperatures.
Application in Metallurgy: Zinc carbonate is an ore that is processed to produce zinc oxide. Zinc oxide is the intermediate compound that is then reduced to extract pure zinc metal.
8. Is zinc carbonate considered toxic?
Yes, zinc carbonate can be toxic if not handled properly. While it is used safely in topical skincare products in low concentrations, it can be harmful if ingested or inhaled. Direct contact may cause irritation to the skin and eyes, and inhaling the dust can lead to respiratory issues. High exposure or ingestion can be harmful, so appropriate safety measures should always be taken when handling it in a laboratory or industrial setting.
