Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, It 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 5th most abundant element in Earth’s crust and the third most abundant metal, after iron and aluminium. The most common Ca 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 Ca.
It was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. It compounds are widely used in many industries, in foods and pharmaceuticals for Ca supplementation, in the paper industry as bleaches, as components in cement and electrical insulators, and in the manufacture of soaps. On the other hand, the metal in pure form has few applications due to its high reactivity; still, in small quantities it is often used as an alloying component in steelmaking, and sometimes, as a calcium lead alloy, in making automotive batteries.
As calcite (calcium carbonate), it occurs on Earth in limestone, chalk, marble, dolomite, eggshells, pearls, coral, stalactites, stalagmites, and the shells of many marine animals. Calcium carbonate deposits dissolve in water that contains carbon dioxide to form calcium bicarbonate, Ca(HCO3)2. This process frequently results in the formation of caves and may reverse to deposit limestone as stalactites and stalagmites. As calcium hydroxyl phosphate, it is the principal inorganic constituent of teeth and bones and occurs as the mineral apatite. As calcium fluoride, it occurs as fluorite, or fluorspar. And as calcium sulfate, it occurs as anhydrite. Calcium is found in many other minerals, such as aragonite (a type of calcium carbonate) and gypsum, and in many feldspars and zeolites. It is also found in a large number of silicates and aluminosilicates, in salt deposits, and in natural waters, including the sea.
Uses Of Calcium
- The element maintains the vital for bones and teeth.
- The element assists in the movement of muscles by helping to carry messages from the brain to all parts of the body.
- The ions of the element act as carriers of between cells in the form of multicellular life forms.
- The element aids in assisting hormones to release along with enzymes.
- This element is widely used in steelmaking because it tends to readily form compounds with oxygen and sulfur.
- It compounds find use in the food industry (as food additives) and the pharmaceutical industry