What are stereoisomers? Give me an example

Question

Lucy Alessi · Accepted Answer

What are stereoisomers? Give me an example

Stereoisomers are molecules that have the same molecular formula and sequence of bonded atoms, but differ in the three-dimensional orientations of their atoms in space.

There are two kinds of stereoisomers: geometric and optical.

Geometric Isomers

Geometric isomers differ in the relative positions of substituents in a rigid molecule.

For example, 1,2-dichloroethene can exist as the cis isomer, with both Cl atoms on the same side of the double bond, or as the trans isomer, with the Cl atoms on opposite sides of the double bond.

Cis and trans isomers have different physical and chemical properties.

Optical Isomers

Optical isomers are molecules whose structures are mirror images that cannot be superimposed on one another in any orientation.

Such molecules are said to be chiral.

For example, D-lactic acid and L-lactic acid are optical isomers.

Optical isomers differ only in their interactions with polarized light and with other chiral molecules.

Zoe Alexander · Answer

undefined Stereoisomers are molecules with the same molecular formula and connectivity of atoms but differ in their spatial arrangement of atoms. An example is cis-trans isomerism in alkenes. In cis-isomers, similar atoms or groups are on the same side, while in trans-isomers, they are on opposite sides.