Stereoisomers are compounds with the same molecular formula but a different spatial arrangement of atoms.
We know that isomers are chemical compounds that have the same molecular formula but a different chemical structure. And that isomers can be sub-classified as a constitutional isomer and a stereoisomer. To determine a constitutional isomer, we must check its connectivity – the difference in functional groups and branching patterns. However, This feature is not exhibited by stereoisomerism, which depends only upon the different spatial arrangement of atoms and no difference in the functional groups. i.e. they have the same constitution. Also, each steroisomer has its pwn set of physical propoerties and cannot be created by conformational change,
The different atomic arrangement gives rise to two types of stereoisomers –
- cis-isomer: In a cis isomer the substituents or groups are on the same side of the atom.
- trans-isomer: In a trans isomer the substituents or groups are not on the same side of the atom.