The acetate anion is C2H3O2?, which can also be written as CH3CO2? or CH3COO-. It contains two atoms of carbon, three atoms of hydrogen and two atoms of oxygen, and carries a total charge of minus one. The acetate anion may also be expressed with the abbreviations OAc? and AcO?.
The term anion refers to substance that contains a negative charge. In contrast, an ion containing a positive charge is known as a cation. The acetate ion is the conjugate base of acetic acid, meaning that it is found when acetic acid dissociates in a solution. When the acetate anion is used to form a molecule with a neutral charge, the resulting molecule is known as an acetate.