Calcium oxide, commonly known as quicklime, is a white, caustic, and crystalline solid with the chemical formula CaO. It is produced by heating calcium carbonate (usually limestone) to high temperatures, causing the release of carbon dioxide. Calcium oxide is highly reactive with water, leading to the production of calcium hydroxide and the release of a significant amount of heat, a process known as slaking. This property makes it valuable in a range of applications, including as a key ingredient in cement production, in agriculture to amend soil pH, and in various industrial processes like metallurgy and the production of chemicals. Its reactivity and versatility in multiple industries underscore its importance as a fundamental chemical compound.