Ammonium dihydrogen phosphate, or monoammonium phosphate, NH₄H₂PO₄, is formed when a solution of phosphoric acid is added to ammonia until the solution is distinctly acidic. It crystallizes in quadratic prisms.

Monopotassium phosphate (also potassium dihydrogen phosphate, KDP, or monobasic potassium phosphate, MKP) -- KH₂PO₄ -- is a soluble salt which is used as a fertilizer, a food additive and a fungicide. It is a source of phosphorus and potassium.

Monosodium phosphate (NaH₂PO₄), also known as anhydrous monobasic sodium phosphate is a chemical compound of sodium with a phosphate counterion. It is used as a laxative and, in combination with other sodium phosphates, as a pH buffer.