Editing Stereocenter (section)

==Stereogenic on other atoms==
Chirality is not limited to carbon atoms, though carbon atoms are often centers of chirality due to their ubiquity in organic chemistry. Nitrogen and phosphorus atoms can also form bonds in a tetrahedral configuration. A nitrogen in an [[amine]] may be a stereocenter if all three groups attached are different because the [[electron pair]] of the amine functions as a fourth group.<ref name=OChemSmith>{{cite book |last1=Smith |first1=Janice Gorzynski |editor1-last=Hodge |editor1-first=Tami |editor2-last=Nemmers |editor2-first=Donna |editor3-last=Klein |editor3-first=Jayne |title=Organic chemistry |date=2011 |publisher=McGraw-Hill |location=New York, NY |isbn=978-0-07-337562-5 |pages=949–993 |edition=3rd |url=http://highered.mheducation.com/sites/007340277x/student_view0/index.html |language=en |format=Book |chapter=Chapter 25 Amines}}</ref> However, [[nitrogen inversion]], a form of [[pyramidal inversion]], causes [[racemization]] which means that both [[epimers]] at that nitrogen are present under normal circumstances.<ref name="OChemSmith" /> Racemization by [[nitrogen inversion]] may be restricted (such as [[quaternary ammonium cation|quaternary ammonium]] or [[phosphonium]] cations), or slow, which allows the existence of chirality.<ref name="OChemSmith" />

Metal atoms with tetrahedral or [[octahedral molecular geometry|octahedral]] geometries may also be chiral due to having different ligands. For the octahedral case, several chiralities are possible. Having three ligands of two types, the ligands may be lined up along the meridian, giving the ''mer''-isomer, or forming a face&mdash;the ''fac'' isomer. Having three bidentate ligands of only one type gives a propeller-type structure, with two different enantiomers denoted Λ and Δ.