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Calcium Carbonate (CaCO₃) — Properties, Uses & Safety

🏠 Everyday & Household

Overview

Chalk, limestone, and marble are all forms of calcium carbonate; also used as an antacid and dietary calcium supplement.

IUPAC Name: calcium carbonate
CAS Number: 471-34-1
PubChem CID: 10112
Molecular Formula: CaCO₃
Molar Mass: 100.09 g/mol
State at STP: solid
Appearance: White powder or crystalline solid

Physical Properties

Melting Point: 825 °C
Density: 2.711 g/cm³
Solubility in Water: 0.013 g/L at 25 °C
ΔH°f: -1206.9 kJ/mol
ΔG°f: -1128.8 kJ/mol

Composition

Element	Count	Mass %
Ca	1	40.04%
C	1	12%
O	3	47.96%

Reactions

Thermal decomposition

CaCO3 → CaO + CO2

decomposition

Acid reaction

CaCO3 + 2 HCl → CaCl2 + H2O + CO2

acid base

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