Final answer:
Stereoisomers with two asymmetric centers and the same configuration are called diastereomers, and they include examples like cis and trans but-2-ene. Meso compounds are an exception, as their internal symmetry makes them achiral despite having asymmetric centers.
Step-by-step explanation:
Stereoisomers with two asymmetric centers are called diastereomers if the configuration of both asymmetric centers in one stereoisomer is the same as the configuration of the asymmetric centers in another stereoisomer. These types of isomers have the same sequence of bonds but different spatial orientations of their atoms or groups of atoms. For instance, the cis and trans isomers of but-2-ene are such diastereomers as their methyl groups are oriented differently in space relative to the double bond. The cis isomer has the methyl groups on the same side, while the trans isomer has them on opposite sides, and neither of these forms mirror each other.
A noteworthy exception when considering stereoisomers with two asymmetric centers is a meso compound, like cis-1,2-dimethylcyclopropane, which does not have enantiomers due to a plane of symmetry within the molecule. Such structures can sometimes but not always be a result of having internal symmetry that compensates for the presence of asymmetric centers, thus rendering the molecule achiral.