WEBPotassium nitrate is a chemical compound with a sharp, salty, bitter taste and the chemical formula K N O 3.It is an ionic salt of potassium ions K + and nitrate ions NO 3 −, and is therefore an alkali metal nitrate.It occurs in nature as a mineral, niter (or nitre in the UK). It is a source of nitrogen, and nitrogen was named after niter.Potassium nitrate is one of …