Characteristic

Monopotassium phosphate, MKP, (also potassium dihydrogenphosphate, KDP, or monobasic potassium phosphate) is the inorganic compound with the formula KH₂PO₄.

Chemical formula:KH₂PO₄

Molar mass:136.086 g/mol

Appearance:White powder, deliquescent

Odor:Odorless

Density:2.338 g/cm³

Melting point:252.6 °C (486.7 °F; 525.8 K)

Boiling point:400 °C (752 °F; 673 K) , decomposes

Solubility in water:22.6 g/100 mL (20 °C);83.5 g/100 mL (90 °C)

Solubility:Slightly soluble in ethanol

Acidity (pKa):6.86

Basicity (pKb):11.9

Refractive index (nD):1.4864

Crystal structure:Tetragonal

Application

Potassium dihydrogen phosphate is used as a food additive, fertilizer (NPK), paint additive, coating additive, adhesive, buffering agent and in optical modulators. It is extensively used in research and analytical laboratories as a buffer in mobile/sample preparations for analysis by high pressure liquid chromatography (HPLC) and also in organic synthesis. MKP, monopotassium phosphate, owing to its non-linear optical properties, is used in optical modulators and for second-harmonic generation (SHG).