Decenoic acid is any mono-carboxylic acid with an unbranched chain of ten carbons connected by eight single bonds and one double bond; that is, a chemical compound with formula HO(O=)C–(CH
2)
k–CH=CH–(CH
2)
7-k–H, where k is between 0 and 7 inclusive.
There are fifteen of these compounds, that can be identified by the position k+2 of the double bond and (for k ≤ 6) the configuration (cis or trans) of the single bonds adjacent to it.
Decenoic acids are technically mono-unsaturated fatty acids (with code C10:1), although they are relatively rare in nature.