Chinese Name: Pyrophosphoric acid Alternative Name: Diphosphoric acid English Name: Pyrophosphoric acid Chemical Formula: H?P?O? Molecular Weight: 177.98 CAS Registry Number: 2466-09-3 Melting Point: 61°C Density: 2.04 g/cm3 Appearance: Colorless liquid Water Solubility: Soluble in water Applications: 1. Analytical reagent, catalyst, metal refining, etc. 2. Used as a catalyst and masking agent; serves as a catalyst, metal refining agent, and stabilizer for organic peroxides. Used in copper electroplating processes to adjust the pH of plating solutions, as well as in other electroplating applications. 3. Employed as an analytical reagent, such as a masking agent, for the preparation of organic phosphates. Used in copper electroplating to regulate the pH of the plating bath, and also applicable to other electroplating processes.