Potassium bisulfate is the potassium salt of bisulfate anion, with the molecular formula KHSO4. This compound is commonly used in the conversion of tartrates to bitartrates in wine. Potassium bisulfate is also used as a disintegrating agent in analytical chemistry.
Mercallite, the mineralogical form of potassium bisulfate, occurs very rarely. Misenite is the other, more complex, potassium hydrogen sulfate.