Zinc Carbonate - ZnCO3

What is Zinc Carbonate?

Zinc carbonate is a white crystalline powder occurs naturally as granular or earthy masses. It is referred as smithsonite or calamine or zinc spar. In pure form it is colourless, transparent but more frequently coloured by the presence of iron, manganese, copper, etc. The ore smithsonite sometimes called “dry bones” contains theoretically 52 percent of metallic zinc.

ZnCO3 Zinc Carbonate
Density ‎3.5 g/cm3
Molecular Weight/ Molar Mass 125.38 g/mol
Stability Stable but incompatible with acids
Boiling Point 333.6 °C at 760 mmHg
Melting Point ~1970 °C
Chemical Formula CO3Zn

Zinc Carbonate Structure – ZnCO3

Zinc carbonate

Physical Properties of Zinc Carbonate – ZnCO3

Odour Faint vinegar odour
Appearance White Powder
Valency Zn = 2

C = 4

O = 2 respectively.

pH Above 10
Oxidation number +2
Solubility Insoluble in water, soluble in dilute acids and alkalis.

Chemical Properties of Zinc Carbonate – ZnCO3

    • Zinc carbonate reacts with acids like hydrochloric acid forms zinc chloride and release carbon dioxide.

ZnCO3 + HCl → ZnCl2 + CO2

    • Zinc carbonate undergoes decomposition forming zinc oxide and carbon dioxide. The chemical reactions is as below.

ZnCO3 → ZnO + CO2

Uses of Zinc Carbonate – ZnCO3

  • Used principally in ointments and takes the place of the former impure carbonate termed calamine.
  • Used in dusting upon inflamed surfaces as an astringent and absorbent.
  • Calamine is a very oil treatment for pruritus. This natural product is zinc carbonate with small quantity of iron oxide.

Health hazard

Zinc intoxication occur both from inhaling zinc fumes and particles, mainly in industrial processes, and oral ingestion results in an excess of zinc in dietary supplements. It causes stomach pains, bleeding and vomiting.

Frequently Asked Questions

What is the use of zinc carbonate?

It is usually used as a barrier against iron and steels which protects against dilapidation. Zinc carbonate can be used on materials, pigments for painting and agricultural stuff. This is also present in zinc anodes known as batteries used on appliances, television monitors and lighting.

Is zinc carbonate acidic or basic?

As with other carbonates, zinc carbonate is readily dissolved in acidic solutions due to its basic nature, but is insoluble in water. The reaction yields carbon dioxide. This will also dissolve to form zincates in an extremely strong base. The zinc carbonate can be decomposed thermally to form zinc oxide.

Is zinc carbonate toxic?

You can be affected by zinc carbonate when you breathe it in. The skin and eyes can get irritated by contact. Zinc carbonate can also irritate the nose and throat causing coughing and wheezing. Elevated exposure can affect the liver.

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