Pyrophosphoric acid is a phosphoric acid derivative with the chemical formula H4P2O7. It is a colorless, viscous liquid that forms through the condensation of two molecules of phosphoric acid, releasing water in the process. This compound is a strong acid and exhibits hygroscopic properties, meaning it can absorb moisture from the air. Due to its unique structure and reactivity, pyrophosphoric acid is utilized in various industrial applications, particularly in the fields of chemistry, agriculture, and materials science.