KH2PO4 0-52-34 Mono Potassium Phosphate Water Soluble Fertilizer Mono Potassium phosphate formula is KH2PO4. When heated to 400 â??, it melts into a transparent liquid and solidifies into opaque glassy potassium metaphosphate after cooling. It is stable in air, soluble in water and insoluble in ethanol. Potassium dihydrogen phosphate is used as buffer and culture agent in industry. It can also be used as a flavoring agent for bacterial culture and synthesis of sake. It is also the raw material for making potassium metaphosphate, the culture agent, fortifier, bulking agent and fermentation assistant of brewing yeast. In agriculture, potassium dihydrogen phosphate is used as high-efficiency phosphorus potassium compound fertilizer.