Sodium hydrogen carbonate and calcium are not the same. Sodium hydrogen carbonate, also known as bicarbonate of soda or baking soda, is a chemical compound with the formula NaHCO3. It is a white, crystalline powder that is soluble in water. Sodium hydrogen carbonate is used as an antacid, a cleaning agent, and a raising agent in baking. Calcium, on the other hand, is a chemical element with the symbol Ca. It is a silvery-white, malleable metal that is the fifth-most abundant element in the Earth's crust. Calcium is used in a variety of applications, including construction, metalworking, and food processing.