Diammonium phosphate (DAP) (chemical formula (NH4)2HPO4, IUPAC name diammonium hydrogen phosphate) is one of a series of water-soluble ammonium phosphate salts which can be produced when ammonia reacts with phosphoric acid.
Dicalcium phosphate, also known as calcium monohydrogen phosphate, is a dibasic calcium phosphate. It is usually found as the dihydrate, with the chemical formula of CaHPO4 H2O, but it can be thermally converted to the anhydrous form. It is practically insoluble in water.
Dipotassium phosphate (K2HPO4) - also phosphoric acid, dipotassium salt; dipotassium hydrogen orthophosphate; potassium phosphate, dibasic - is a highly water-soluble salt which is often used as a fertilizer, food additive and buffering agent.
Disodium hydrogen phosphate (Na2HPO4) is a sodium salt of phosphoric acid. It is a white powder that is highly hygroscopic and water soluble. It is therefore used commercially as an anti-caking additive in powdered products.