Diphenyl ether is an organic compound with the chemical formula C12H10O. It consists of two phenyl groups connected by an oxygen atom. This colorless liquid has a high boiling point and is used in various applications, including as a solvent and in the production of certain chemicals. In addition to its industrial uses, diphenyl ether is also found in some household products, such as antifreeze and de-icing agents. Its properties make it useful in the manufacturing of flame retardants and as a heat transfer fluid in certain systems.