WHAT IS CALCIUM CARBONATE?
Calcium carbonate refers to CaCO3, details of which can be found below:-
https://www.meritnation.com/ask-answer/question/how-is-calcium-carbonate-formed-mention-some-of-its-uses/chemical-reactions-and-equations/5929754
https://www.meritnation.com/ask-answer/question/how-is-calcium-carbonate-formed-mention-some-of-its-uses/chemical-reactions-and-equations/5929754