Calcium carbonate
Molar mass: 100.09 g/mol · Class: Ionic salt
Elements: calcium, carbon, oxygen
Structure
The solid is an ionic lattice of Ca2+ ions and flat, triangular carbonate ions. Different crystal arrangements give calcite (limestone, marble) and aragonite (pearls, shells).
Properties
White solid, practically insoluble in pure water
Reacts with acids to release carbon dioxide gas
Decomposes on strong heating to calcium oxide and CO2
Main component of limestone, chalk, and marble
Applications
Cement and concrete production
Antacid tablets for heartburn
Agricultural lime to reduce soil acidity
Filler in paper, plastics, and paint
Low toxicity as a solid, but fine dust irritates eyes and lungs: wear a dust mask when handling powder. Keep antacid use within labeled doses; excess calcium can cause problems.
Data source: IUPAC standard atomic weights 2021; molar mass computed from CaCO3