Monoammonium Phosphate (MAP)

About This Product

Monoammonium phosphate, MAP, has the formula NH4H2PO4 and CAS number 7722-76-1. It is supplied as white crystals or granules, readily water-soluble, giving a mildly acidic solution around pH 4.5. In agriculture it is valued for nutrient density: at 11 percent nitrogen and 52 percent phosphorus pentoxide it carries more phosphorus per tonne than any other widely traded straight fertiliser, which cuts freight and handling cost per unit of nutrient. Its mild acidity also helps in calcareous soils, where alkaline conditions lock phosphorus into insoluble calcium compounds; the acidic reaction zone around a dissolving MAP granule keeps phosphorus available to the root for longer. Its second major use is entirely unrelated. MAP is the active constituent of ABC dry chemical fire extinguishers, where it works on all three fire classes: it melts and flows over burning solids to form a barrier layer that smothers class A fires, while decomposing endothermically to absorb heat and interrupt the flame chemistry of class B and C fires. It is used in fertilisers and fertigation, ABC dry chemical fire extinguishers, flame retardants, fermentation nutrition and metal treatment. Bio Green Chem supplies MAP to specification on nitrogen and P2O5 content, water-soluble phosphorus, pH, moisture, particle size and heavy metals.