Editing Stereochemistry (section)

==Types==

=== Atropisomers ===
[[Atropisomer|Atropisomerism]] derives from the inability to rotate about a bond, such as due to [[Steric effects|steric hindrance]] between functional groups on two sp<sup>2</sup>-hybridized carbon atoms.  Usually atropisomers are chiral, and as such they are a form of [[axial chirality]]. Atropisomerism can be described as conformational isomerism

:[[Image:Atropisomer.svg|class=skin-invert-image|300px]]

=== Cis-Trans isomers ===
[[Cis–trans isomerism|Cis-Trans isomers]] are often associated [[alkene]] double bonds.
:{| class=skin-invert-image
|-
| align=center | [[File:(Z)-pent-2-ène.svg|200px]]
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
| align=center | [[File:(E)-pent-2-ène.svg|200px]]
|-
| align=center | ''cis''-pent-2-ene
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
| align=center | ''trans''-pent-2-ene
|}

The more general ''E''/''Z'' nomenclature refers to the concept of ''cis''/''trans'' isomerism, and is especially useful for more complex compounds.

:{| class="skin-invert-image"
|-
| align=center | [[File:(Z)-1-Bromo-1,2-dichloroethene.svg|120px]]
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
| align=center | [[File:(E)-1-Bromo-1,2-dichloroethene.svg|120px]]
|-
| align=center | (''Z'')-1-Bromo-1,2-dichloroethene
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
| align=center | (''E'')-1-Bromo-1,2-dichloroethene
|}

=== Diastereomers ===
[[Diastereomer|Diastereomers]] are non-superposable, non-identical stereoisomers. A common example of diastereomerism is when two compounds differ from each other by the (''R'')/(''S'') [[absolute configuration]] at some, but not all corresponding stereocenters. Epimers are diastereomers that differ at exactly one such position. ''cis''/''trans'' isomerism is another type of diastereomeric relationship.

* '''Example:''' The below pair can also be classified as [[Epimer|epimers]].

:[[File:Diastereomer pair.png|class=skin-invert-image|400px]]

=== Enantiomers ===
[[Enantiomer]]s are pairs of non-superposable mirror images. Each member of the pair has a distinct [[Absolute configuration|R]].
:[[File:Butan-2-ol enantiomers.jpeg|class=skin-invert-image|400px]]

=== Epimers ===
[[Epimer]]s are a subcategory of diastereomers that differ in absolute configuration configurations at only one corresponding stereocenter. They are commonly found in [[Sugar (chemistry)|sugar chemistry]], where two sugars can differ by the configuration of a single carbon atom.

* '''Example''': D-glucose and D-galactose are epimers, differing only at the C-4 position in their structure. (see [[Sugar (chemistry)|sugar numbering]])

:[[File:Epimers.png|class=skin-invert-image|300px]]