Why are cis and trans isomers of succinic acid impossible?

Succinic acid is a dicarboxylic acid with the molecular formula C4H6O4.

​. The carbon atoms in succinic acid are arranged in a straight chain, and it does not have cis and trans isomers in the same way that some compounds with double bonds exhibit cis-trans isomerism.

Cis-trans isomerism typically occurs in compounds with double bonds (alkenes) or rings, where the arrangement of substituents around the double bond or in the ring can be either on the same side (cis) or opposite sides (trans). Succinic acid does not contain a double bond or a ring, so the concept of cis-trans isomerism is not applicable to its structure.

In the case of succinic acid, the carbon atoms are connected by single bonds, and the molecule has a linear structure. The isomerism it exhibits is positional isomerism, which means that the carboxyl groups can be arranged in different positions along the carbon chain. The two possible positional isomers of succinic acid are:

1. 1,2-Butanedicarboxylic acid: Carboxyl groups are attached to carbon atoms 1 and 2.
2. 1,3-Butanedicarboxylic acid: Carboxyl groups are attached to carbon atoms 1 and 3.