CAS 13598-36-2 Phosphorous Acid H3PO3 Chemical Additives Agrochemical Intermediates Food Industrial Grade Basic Information Model Number : HM03003 Other Names : PA ; PPA ;Phosphonic Acid ; Hydrogen Phosphonate Molecular Formula : H3PO3 Molecular Weight : 82.00 CAS NO. : 13598-36-2 EINECS NO. : 237-066-7 Standard : HG/T2520-2006 Purity : 99% min. Applications In the plastic industry , it is mainly used as a reducing agent , nylon whitening agent , plasticizer , synthetic fiber , etc . It is also used in the production of herbicides , fungicides and water stabilizers in the organophosphorus pesticide industry . It is also used to produce ATMP , a high-performance water treatment agent .