Di-ammonium-phosphate

These Di-Ammonium-Phosphate (DAP) (chemical formula (NH4)2HPO4, IUPAC name diammonium hydrogen phosphate) is one of a series of water-soluble ammonium phosphate salts that can be produced when ammonia reacts with phosphoric acid. Solid diammonium phosphate shows a dissociation pressure of ammonia as given by the following expression and equation.
(NH4)2HPO4(s) NH3(g) + NH4H2PO4(s) log PmmHg = a 3063 / T + 175 log T + 3.3
where:
P = the resultant dissociation pressure of ammoniaT = absolute temperature (K)
At 100A C, the dissociation pressure of diammonium phosphate is approximately 5 mmHg
DAP is used as a fertilizer. When applied as plant food, it temporarily increases the soil pH, but over a long term the treated ground becomes moreacidic than before upon nitrification of the ammonium. It is incompatible with alkaline chemicals because its ammonium ion is more likely to convert toammonia in a high-pH environment. The average pH in solution is 7.5a 8. The typical formulation is 18-46-0 NPK
DAP can be used as a fire retardant. It lowers the combustion temperature of the material, decreases maximum weight loss rates, and causes an increase in the production of residue or char.[5] These are important effects in fighting wildfires as lowering the pyrolysis temperature and increasing the amount of char formed reduces that amount of available fuel and can lead to the formation of a firebreak. It is the largest component of some popular commercial firefighting products.