What is the chemical formula for limestone?

Limestone is primarily composed of calcium carbonate, which is represented by the chemical formula CaCO3. This compound consists of one calcium ion (Ca^2+) and one carbonate ion (CO3^2-). The presence of these ions combined in this way constitutes the mineral structure of limestone, making it an essential component in various geological processes and a key material in construction and industry.

Understanding the components of the formula, calcium (Ca) and carbonate (CO3), is crucial since it reflects the properties of limestone, such as its ability to react with acids and dissolve in water under certain conditions. This reaction is significant in geological formations and in the production of lime for various industrial purposes.

The other formulas listed do not represent limestone; rather, they correspond to different substances. For instance, CaCO2 is not a commonly recognized compound relevant to limestone. C3H6O3 refers to a type of organic acid (like lactic acid), and CaO is calcium oxide, which is obtained from heating limestone and is used for a variety of chemical processes but is not limestone itself.