Calcium Calcium Calcium is a chemical element with symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The
Calcium lactate 75% relative humidity. Calcium lactate can be prepared by the reaction of lactic acid with calcium carbonate or calcium hydroxide. Since the 19th century, the salt has been obtained industrially by fermentation of carbohydrates in the presence of calcium mineral sources such as calcium carbonate or calcium hydroxide. Fermentation may produce either D or L lactate, or a racemic mixture of both, depending on the type of organism used. Calcium lactate has several uses in human and veterinary medicine. Calcium lactate is used in medicine as an antacid. Calcium lactate is also used to treat hypocalcaemia (calcium deficiencies). It can