AVA Chemicals [P] Ltd. Manufactures Extra Pure Grade Mono Ammonium Phosphate. AVA Chemicals [P] Ltd. Is an ISO 9001:2000 certified company. Extra Pure Grade Mono Ammonium Phosphate has a White Crystals appearance. The chemical Formula of Extra Pure Grade Mono Ammonium Phosphate is NH4 H2 PO4 and its molecular weight is 115. The assay of this chemical is minimum 99 percent. Ph of a 5% Solution of Extra Pure Grade Mono Ammonium Phosphate is 4.0 to 4.5.