An acetate is a salt formed by the combination of acetic acid with a base. "Acetate" also describes the conjugate base or ion typically found in aqueous solution and written with the chemical formula C2H3O−2. The neutral molecules formed by the combination of the acetate ion and a positive ion are also commonly called "acetates". The simplest of these is hydrogen acetate with corresponding salts, esters, and the polyatomic anion CH3CO−2, or CH3COO−.