When calcium carbonate (CaCO₃) is heated strongly, it undergoes thermal decomposition, breaking down into two compounds:

* Calcium oxide (CaO), also known as quicklime.

* Carbon dioxide (CO₂) , a colorless gas.

The chemical equation for this reaction is:

CaCO₃(s) → CaO(s) + CO₂(g)

This reaction is commonly used in the production of lime (CaO), which has various industrial applications.