An acetate, or ethanoate, is a salt or ester of acetic acid.

Acetate

The acetate anion, ⁻, is a carboxylate and is the conjugate base of acetic acid. The acetate ion is formed by the deprotonation of acetic acid:

Acetate esters

An acetate ester is an ester of acetic acid, with the general formula CH₃COOR, where R is an organyl group.

Acetate can also refer to cellulose acetate, especially fibres or other derived products such as the acetate disc used in audio record production. Cellulose acetate can be found in many household products.

Notation in organic chemistry

In the field of organic chemistry the abbreviation Ac refers to the acetyl group. Hence, acetate can be written ⁻OAc or AcO⁻ and acetic acid, sodium acetate, and ethyl acetate can be denoted by HOAc, NaOAc, and EtOAc respectively.

Ac is also the symbol for the chemical element actinium, but confusion between actinium and the acetyl group is rare, since actinium has virtually no role in organic chemistry.

Structures