Litharge is a type of lead oxide with the chemical formula PbO. It is also known as lead monoxide or lead protoxide. Litharge is a yellowish-orange or reddish-brown powder that is produced by heating lead in the air. It is used in a variety of applications, including as a pigment, a glaze in ceramics, and as a component in lead-acid batteries.

In the manufacturing of glass, litharge is used as a fluxing agent to lower the melting point of silica, which is the main ingredient in glass. It is also used in the production of enamels, where it acts as a flux to help the enamel adhere to the metal surface.

In the production of lead-acid batteries, litharge is used as a key component in the positive electrodes. It is mixed with other materials such as lead, sulfuric acid, and water to form a paste, which is then applied to the battery plates. The litharge reacts with the sulfuric acid to form lead sulfate and lead dioxide, which are critical components in the battery's operation.