Calcium citrate

Formula : C12-H10-Ca3-O14.4H2-O
CAS : 5785-44-4 

A colorless crystalline or white powdery organic, tricarboxylic acid occurring in plants, especially citrus fruits, and used as a flavoring agent, as an antioxidant in foods, and as a sequestrating agent. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)