... heavy metal Diammonium phoshphate(DAP 21-53-0)Molecular Formula:(NH4)2HPO4, Molecular Weight:132.0, Appearance: white crystal,Assay:99%min ... ,P2O5:53%min,N:21.0%min, pH:7.8 ... -8.2, Insoluble matter :0.10% max, Moisture:0.2%max DAP is used as a fertilizer. When applied ...