Monopotassium phosphate (also potassium dihydrogen phosphate, KDP, or monobasic potassium phosphate, MKP) -- ₂₄ -- is a soluble salt which is used as a fertilizer, a food additive and a fungicide. It is a source of phosphorus and potassium, and is a buffering agent. When used in fertilizer mixtures with urea and ammonium phosphates, it minimizes escape of ammonia by keeping the pH at a relatively low level.

Fertilizer grade MKP contains 52% P₂O₅ and 34% K₂O, and is labeled 0-52-34. It is often used as a nutrient source in the greenhouse trade and in hydroponics.

It is one of the components of Gatorade and is used as an additive in cigarettes.

At 400°C it decomposes, by loss of water, to potassium metaphosphate (KPO₃)

Nonlinear optics use

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As a crystal, it is noted for its non-linear optical properties. Used in optical modulators and for non-linear optics such as SHG (second harmonic generation).

Also to be noted is KD*P, Potassium DiDeuterium Phosphate, KD₂PO₄. Also used for similar applications with slighty different properties.

External links

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• EPA: Potassium dihydrogen phosphate Fact Sheet
• Potassium Phosphate - a Hydroculture Salt

Phosphates | Potassium compounds | Nonlinear optical materials