What are meso isomers?

1 Answer
Jul 3, 2018

A #"meso isomer"# is a symmetric #"RS"# speices such that....

Explanation:

A #"meso isomer"# is a symmetric #"RS"# molecule such that inversion in a mirror plane results in the same molecule.

And this is best illustrated by an example...

#H_3C-stackrel"*"CH(OH)CH_2stackrel"*"CH(OH)CH_3#...

The potentially chiral carbons are marked with a #"*"#. While #"RR"# and #"SS"# are indeed enantiomeric, #"RS"# is EQUIVALENT to #"SR"# by the internal mirror plane. And so the simple answer is that a meso compound is a symmetric #"RS"# diastereomer...