Isomers

Isomer

different compounds with the same molecular formula

Stereoisomers

isomers that differ only in the arrangement of atoms in space

structural (constitutional) isomers

isomers that differ in the order in which atoms are bonded together

configurational isomers

stereoisomers that can only be interconverted through bond breakage (isolable at room temperature)

diastereomers

configurational isomers that are not mirror images of one another

geometric(al) isomers

diastereomers that differ in their cis-trans arrangement on a ring or double bond

enantiomers

mirror-image, non-superimposable stereoisomers

conformational isomers

stereoisomers related by rotations about a single bond (generally noticeable at room temperature)

conformational enantiomers

enantiomers related by rotation about bonds (see above forms of n-butane)