These are chemical compounds involving calcium:

Ca - Calcium is a chemical element with the symbol Ca and atomic number 20.

CaH2 - Calcium hydride is a compound with the formula CaH2, which is a white powder that reacts with water to release hydrogen gas.

CaCO3 - Calcium carbonate is a common compound found in rocks and minerals, as well as in shells of marine organisms like snails and oysters.

CaCl2 - Calcium chloride is a salt that is commonly used as a de-icer for roads and sidewalks in winter, as well as in various industrial processes.

Ca3(PO4)2 - Calcium phosphate is a compound composed of calcium cations and phosphate anions, and is an important mineral in the human body for bone health.