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.

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