What distinguishes diastereomers from other isomers?

Diastereomers are a specific type of stereoisomer that are not mirror images of each other, unlike enantiomers, which are optical isomers and do have this property. The correct response highlights that diastereomers possess different physical and chemical properties, which can include differences in boiling points, melting points, solubility, and reactivity. This distinction arises from the arrangement of atoms in space that leads to variations in how these molecules interact with other substances, which is not the case for enantiomers.

For instance, consider two diastereomers: they may have the same molecular formula and connectivity of atoms, yet their three-dimensional structures differ, leading to unique interaction scenarios. This can be crucial in biological systems, where different stereoisomers can have vastly different functions and roles.

In contrast, molecules that are mirror images refer specifically to enantiomers, making them distinct from diastereomers. Molecules with identical properties would not represent diastereomers but would instead suggest they are the same compound or conformational isomers, which also does not apply to diastereomers as they consistently manifest differences in behavior.