why does acetate have two different ways of writing it
Acetate When part of a salt, the formula of the acetate ion is written as CH3CO2−, C2H3O2−, or CH3COO−. Chemists abbreviate acetate as OAc− or, less commonly, AcO−. Thus, HOAc is the abbreviation for acetic acid, NaOAc for sodium acetate, and EtOAc for ethyl acetate.[2] The abbreviation "Ac" (or "AC") is also sometimes encountered in chemical formulas to indicate the acetate ion (CH3CO2−), or the acetyl group (CH3CO). This abbreviation is not to be confused with the symbol of actinium, the first element of the actinide series. For example, the formula for sodium acetate might be abbreviated as "NaAc", rather than "NaC2H3O2". Care should also be taken to avoid confusion with peracetic acid when using the OAc abbreviation; for clarity and to avoid errors when translated, HOAc should be avoided in literature mentioning both compounds.