After mentioning some legal implications of chirality, the discussion of
configuration concludes using esomeprazole as an example of three
general methods for producing single enantiomers. Conformational
isomerism is more subtle because isomers differ only by rotation about
single bonds, which requires careful physico-chemical consideration of
energies and their relation to equilibrium and rate constants.
Conformations have their own notation and nomenclature. Curiously, the
barrier to rotation about the C-C bond of ethane was established by
measuring its heat capacity.