👉 Nitrate is a chemical compound consisting of two nitrogen atoms and one sulfur atom. It has the formula NO3- (or N2O5 - or NH4NO3). Nitrate is commonly used as an oxidizing agent in biological processes, particularly in the production of nitrites (a type of nitrate that is useful for food preservation), which are important in the production of nitrogenous compounds. It can also be used to purify water and other substances by reacting with a base