Calcium oxide, CaO, is an ionic compound that has one cation with a positive valency and one anion with a negative valency. The bond between the two ions is ionic, and it is based on the positive ions attracting the negative ions.
The melting point of cao is 2572 degrees Celsius. It is commonly used in the basic oxygen steelmaking process and as a component of glass. It is also used in the production of various chemicals and a variety of cements.
In glass making, it is used in the production of a variety of glasses, especially plate and sheet glass and containers. It is also used to produce ceramic glazes that are hard and have a high fire resistance.
It is produced by the thermal decomposition of materials containing calcium carbonates (CaCO3; mineral calcite) in a rotary kiln. The chemical reaction is held at elevated temperatures to ensure that the temperature remains below the melting point. The product of this reaction is called burnt lime.
Several other chemical applications of CaO are in the paper industry and the petroleum industry. Water detection pastes used in fuel storage tanks contain a mix of CaO and phenolphthalein to detect the presence of water. The phenolphthalein reacts with the CaO to form calcium hydroxide, which is an indicator of water.
The chemistry of calcium oxide is a complex and intricate one, and there are many theoretical researches on the molecule, its crystal structures, physical properties, and structural phase transitions. These include first-principles calculations and classical molecular dynamics (CMD) simulations based on interatomic potentials.