Editing VSEPR theory (section)

===Transition metals (Kepert model)===
The lone pairs on [[transition metal]] atoms are usually stereochemically inactive, meaning that their presence does not change the molecular geometry. For example, the hexaaquo complexes M(H<sub>2</sub>O)<sub>6</sub> are all octahedral for M = V<sup>3+</sup>, Mn<sup>3+</sup>, Co<sup>3+</sup>, Ni<sup>2+</sup> and Zn<sup>2+</sup>, despite the fact that the electronic configurations of the central metal ion are d<sup>2</sup>, d<sup>4</sup>, d<sup>6</sup>, d<sup>8</sup> and d<sup>10</sup> respectively.<ref name=Housecroft/>{{rp|542}} The Kepert model ignores all lone pairs on transition metal atoms, so that the geometry around all such atoms corresponds to the VSEPR geometry for AX<sub>n</sub> with 0 lone pairs E.<ref>{{cite journal |last1=Anderson |first1=O. P. |title=Book reviews: Inorganic Stereochemistry (by David L. Kepert) |journal=Acta Crystallographica B |date=1983 |volume=39 |pages=527–528 |doi=10.1107/S0108768183002864 |url=https://journals.iucr.org/b/issues/1983/04/00/a22157/a22157.pdf |access-date=14 September 2020 |quote=based on a systematic quantitative application of the common ideas regarding electron-pair repulsion|doi-access=free }}</ref><ref name=Housecroft/>{{rp|542}} This is often written ML<sub>n</sub>, where M = metal and L = ligand. The Kepert model predicts the following geometries for coordination numbers of 2 through 9:

{| class="wikitable" style="margin:1em auto;"
|- 
! Molecule <br>type
! Shape
! Geometry
! Examples
|- 
! ML<sub>2</sub>
| [[Linear (chemistry)|Linear]]
| [[File:Linear-3D-balls.png|100px]]
| [[mercury(II) chloride|HgCl<sub>2</sub>]]<ref name=Jolly/>
|- 
! ML<sub>3</sub>
| [[Trigonal planar]]
| [[File:Trigonal-3D-balls.png|100px]]
|
|- 
! ML<sub>4</sub>
| [[Tetrahedral molecular geometry|Tetrahedral]]
| [[File:Tetrahedral-3D-balls.png|100px]]
| [[Tetrachloronickelate|{{chem|NiCl|4|2-}}]]
|- 
! rowspan="2"| ML<sub>5</sub>
| [[Trigonal bipyramidal molecular geometry|Trigonal bipyramidal]]
| [[File:Trigonal-bipyramidal-3D-balls.png|100px]]
| [[Iron pentacarbonyl|{{chem|Fe(CO)|5}}]]
|-
| [[Square pyramidal molecular geometry|Square pyramidal]]
| [[File:Square-pyramidal-3D-balls.png|100px]]
| MnCl<sub>5</sub><sup>2−</sup>
|-
! ML<sub>6</sub>
| [[Octahedral molecular geometry|Octahedral]]
| [[File:Octahedral-3D-balls.png|100px]]
| [[tungsten hexachloride|WCl<sub>6</sub>]]<ref name=Housecroft/>{{rp|659}}
|-
! rowspan="3"| ML<sub>7</sub>
| [[Pentagonal bipyramidal molecular geometry|Pentagonal bipyramidal]]<ref name=Miessler/>
| [[File:Pentagonal-bipyramidal-3D-balls.png|100px]]
| {{chem|ZrF|7|3-}}
|-
| [[Capped octahedral molecular geometry|Capped octahedral]]
| [[File:Face-capped octahedron.png|100px]]
| {{chem|MoF|7|-}}
|-
| [[Capped trigonal prismatic molecular geometry|Capped trigonal prismatic]]
| [[File:MonocappTrigPrism.CapRightps.png|100px]]
| {{chem|TaF|7|2-}}
|-
! rowspan="3"| ML<sub>8</sub>
| [[Square antiprismatic molecular geometry|Square antiprismatic]]<ref name=Miessler/>
| [[File:Square-antiprismatic-3D-balls.png|100px]]
| {{chem|ReF|8|-}}
|-
| [[Dodecahedral molecular geometry|Dodecahedral]]
| [[File:Snub disphenoid.png|100px]]
| {{chem|Mo(CN)|8|4-}}
|-
| [[Bicapped trigonal prismatic molecular geometry|Bicapped trigonal prismatic]]
| [[File:Square face bicapped trigonal prism.png|100px]]
| {{chem|ZrF|8|4-}}
|-
! rowspan="2"| ML<sub>9</sub>
| [[Tricapped trigonal prismatic molecular geometry|Tricapped trigonal prismatic]]
| [[File:AX9E0-3D-balls.png|110px]]
| [[Potassium nonahydridorhenate|{{chem|ReH|9|2-}}]]<ref name=Housecroft/>{{rp|254}}
|-
| [[Capped square antiprismatic molecular geometry|Capped square antiprismatic]]
| [[File:Monocapped square antiprism.png|110px]]
|
|}