Chemical database: 28. Calcium oxide

Calcium oxide (CaO), also known as quicklime, is a relatively widely used inorganic salt. It has a white color, and is caustic and alkaline. Density = 3.35 g/cm3. Melting point = 2572°C. Boiling point = 2850°C. It is used in pottery, in the production of paints, in the food industry, in the production of construction materials, and also as an energy source (when mixed with water). Calcium oxide is also thought to have been one of the components of Greek fire - one of the early thermal weapons used by mankind.

Calcium oxide can be bought usually in large bags at stores that sell construction materials and equipment. However, the quality of such calcium oxide can vary a lot, since this compound easily forms calcium hydroxide when in contact with water. Fortunately, the hydroxide can simply be converted back to the oxide by heating it to about 512°C.