Editing VSEPR theory (section)

===Main-group elements===
For [[main-group element]]s, there are stereochemically active [[lone pair]]s ''E'' whose number can vary from 0 to 3. Note that the geometries are named according to the atomic positions only and not the electron arrangement. For example, the description of AX<sub>2</sub>E<sub>1</sub> as a bent molecule means that the three atoms AX<sub>2</sub> are not in one straight line, although the lone pair helps to determine the geometry.

{| class="wikitable" style="margin:1em auto;"
!Steric <br> number
!Molecular geometry<ref name=PetrucTable>{{cite book|last1=Petrucci |first1=R. H. |first2=Harwood |last2=W. S. |first3=Herring |last3=F. G. |title=General Chemistry: Principles and Modern Applications |publisher=Prentice-Hall |edition=8th |year=2002 |pages=413–414 (Table 11.1) |isbn=978-0-13-014329-7}}</ref> <br> 0 lone pairs
!Molecular geometry<ref name=Petrucci/>{{rp|413–414}}<br> 1 lone pair
!Molecular geometry<ref name=Petrucci/>{{rp|413–414}}<br> 2 lone pairs
!Molecular geometry<ref name=Petrucci/>{{rp|413–414}}<br> 3 lone pairs
|-
!2 
| [[File:AX2E0-2D.png|128px]] <br> {{center|[[Linear (chemistry)|Linear]]}} || &nbsp; || &nbsp; || &nbsp;
|-
!3 
| [[File:AX3E0-side-2D.png|128px]] <br> {{center|[[Trigonal planar]]}} || [[File:AX2E1-2D.png|128px]] <br> {{center|[[Bent (chemistry)|Bent]]}} ||&nbsp; ||&nbsp;
|-
!4 
| [[File:AX4E0-2D.svg|128px]] <br> {{center|[[Tetrahedral molecular geometry|Tetrahedral]]}} || [[File:AX3E1-2D.png|128px]] <br> {{center|[[Trigonal pyramidal molecular geometry|Trigonal pyramidal]]}} || [[File:AX2E2-2D.png|128px]]  <br> {{center|[[Bent (chemistry)|Bent]]}} ||&nbsp; 
|-
!5 
| [[File:AX5E0-2D.png|128px]] <br> {{center|[[Trigonal bipyramidal molecular geometry|Trigonal bipyramidal]]}} || [[File:AX4E1-2D.png|128px]] <br> {{center|[[Seesaw (chemistry)|Seesaw]]}} || [[File:AX3E2-2D.png|128px]] <br> {{center|[[T-shaped (chemistry)|T-shaped]]}} || [[File:AX2E3-2D.png|128px]] <br> {{center|[[Linear (chemistry)|Linear]]}}
|-
!6 
| [[File:AX6E0-2D.svg|128px]]  <br> {{center|[[Octahedral molecular geometry|Octahedral]]}} || [[File:AX5E1-2D.png|128px]]  <br> {{center|[[Square pyramidal molecular geometry|Square pyramidal]]}} || [[File:AX4E2-2D.png|128px]] <br> {{center|[[Square planar]]}} || &nbsp;
|-
!7 
| [[File:AX7E0-2D.png|128px]] <br> {{center|[[Pentagonal bipyramidal molecular geometry|Pentagonal bipyramidal]]}} ||[[File:AX6E1-2D.png|128px]] <br> {{center|[[Pentagonal pyramidal molecular geometry|Pentagonal pyramidal]]}} ||[[File:AX5E2-2D.png|128px]] <br> {{center|[[Pentagonal planar molecular geometry|Pentagonal planar]]}} || &nbsp;
|-
!8 
| <br> {{center|[[Square antiprismatic molecular geometry|Square antiprismatic]]<br> }} || <br> &nbsp; || &nbsp; || &nbsp;
|}

{{Clear}}
{| class="wikitable" style="margin:1em auto;"
|- 
! Molecule <br>type
! Molecular Shape<ref name=Petrucci/>{{rp|413–414}}
! Electron Arrangement<ref name=Petrucci/>{{rp|413–414}} <br> <small>including lone pairs, shown in yellow</small>
! Geometry<ref name=Petrucci/>{{rp|413–414}} <br> <small>excluding lone pairs</small>
! Examples
|- 
! AX<sub>2</sub>E<sub>0</sub>
| [[Linear (chemistry)|Linear]]
| [[File:AX2E0-3D-balls.png|100px]]
| [[File:Linear-3D-balls.png|100px]]
| [[beryllium chloride|BeCl<sub>2</sub>]],<ref name=Jolly/> [[carbon dioxide|CO<sub>2</sub>]]<ref name=Miessler/>
|- 
! AX<sub>2</sub>E<sub>1</sub>
| [[Bent (chemistry)|Bent]]
| [[File:AX2E1-3D-balls.png|100px]]
| [[File:Bent-3D-balls.png|100px]]
| [[nitrite|{{chem|NO|2|-}}]],<ref name=Jolly/> [[sulfur dioxide|SO<sub>2</sub>]],<ref name=Petrucci/>{{rp|413–414}} [[ozone|O<sub>3</sub>]],<ref name=Jolly/> [[dichlorocarbene|CCl<sub>2</sub>]]
|-
! AX<sub>2</sub>E<sub>2</sub>
| [[Bent (chemistry)|Bent]]
| [[File:AX2E2-3D-balls.png|100px]]
| [[File:Bent-3D-balls.png|100px]]
| [[water (molecule)|H<sub>2</sub>O]],<ref name=Petrucci/>{{rp|413–414}} [[oxygen difluoride|OF<sub>2</sub>]]<ref name=Housecroft/>{{rp|448}}
|- 
! AX<sub>2</sub>E<sub>3</sub>
| [[Linear (chemistry)|Linear]]
| [[File:AX2E3-3D-balls.png|100px]]
| [[File:Linear-3D-balls.png|100px]]
| [[xenon difluoride|XeF<sub>2</sub>]],<ref name=Petrucci/>{{rp|413–414}} [[triiodide|{{chem|I|3|-}}]],<ref name=Housecroft/>{{rp|483}} [[xenon dichloride|XeCl<sub>2</sub>]]
|- 
! AX<sub>3</sub>E<sub>0</sub>
| [[Trigonal planar]]
| [[File:AX3E0-3D-balls.png|100px]]
| [[File:Trigonal-3D-balls.png|100px]]
| [[boron trifluoride|BF<sub>3</sub>]],<ref name=Petrucci/>{{rp|413–414}} [[carbonate|{{chem|CO|3|2-}}]],<ref name=Housecroft/>{{rp|368}} [[formaldehyde|{{chem|CH|2|O}}]], [[nitrate|{{chem|NO|3|-}}]],<ref name=Jolly/> [[sulfur trioxide|SO<sub>3</sub>]]<ref name=Miessler/>
|- 
! AX<sub>3</sub>E<sub>1</sub>
| [[Trigonal pyramid (chemistry)|Trigonal pyramidal]]
| [[File:AX3E1-3D-balls.png|100px]]
| [[File:Pyramidal-3D-balls.png|100px]]
| [[ammonia|NH<sub>3</sub>]],<ref name=Petrucci/>{{rp|413–414}} [[phosphorus trichloride|PCl<sub>3</sub>]]<ref name=Housecroft/>{{rp|407}}
|- 
! AX<sub>3</sub>E<sub>2</sub>
| [[T-shaped molecular geometry|T-shaped]]
| [[File:AX3E2-3D-balls.png|100px]]
| [[File:T-shaped-3D-balls.png|100px]]
| [[chlorine trifluoride|ClF<sub>3</sub>]],<ref name=Petrucci/>{{rp|413–414}} [[bromine trifluoride|BrF<sub>3</sub>]]<ref name=Housecroft/>{{rp|481}}
|- 
! AX<sub>4</sub>E<sub>0</sub>
| [[Tetrahedral molecular geometry|Tetrahedral]]
| [[File:AX4E0-3D-balls.png|100px]]
| [[File:Tetrahedral-3D-balls.png|100px]]
| [[methane|CH<sub>4</sub>]],<ref name=Petrucci/>{{rp|413–414}} [[phosphate|{{chem|PO|4|3-}}]], [[sulfate|{{chem|SO|4|2-}}]],<ref name=Miessler/> [[perchlorate|{{chem|ClO|4|-}}]],<ref name=Jolly/> [[xenon tetroxide|XeO<sub>4</sub>]]<ref name=Housecroft/>{{rp|499}}
|- 
! AX<sub>4</sub>E<sub>1</sub>
| [[Seesaw (chemistry)|Seesaw]] or [[disphenoid]]al
| [[File:AX4E1-3D-balls.png|100px]]
| [[File:Seesaw-3D-balls.png|100px]]
| [[sulfur tetrafluoride|SF<sub>4</sub>]]<ref name=Petrucci/>{{rp|413–414}}<ref name=Housecroft/>{{rp|45}}
|- 
! AX<sub>4</sub>E<sub>2</sub>
| [[Square planar molecular geometry|Square planar]]
| [[File:AX4E2-3D-balls.png|100px]]
| [[File:Square-planar-3D-balls.png|100px]]
| [[xenon tetrafluoride|XeF<sub>4</sub>]]<ref name=Petrucci/>{{rp|413–414}}
|- 
! AX<sub>5</sub>E<sub>0</sub>
| [[Trigonal bipyramidal molecular geometry|Trigonal bipyramidal]]
| [[File:Trigonal-bipyramidal-3D-balls.png|100px]]
| [[File:Trigonal-bipyramidal-3D-balls.png|100px]]
| [[phosphorus pentachloride|PCl<sub>5</sub>]],<ref name=Petrucci/>{{rp|413–414}} [[phosphorus pentafluoride|PF<sub>5</sub>]],<ref name=Petrucci/>{{rp|413–414}}
|- 
! AX<sub>5</sub>E<sub>1</sub>
| [[Square pyramidal molecular geometry|Square pyramidal]]
| [[File:AX5E1-3D-balls.png|100px]]
| [[File:Square-pyramidal-3D-balls.png|100px]]
| [[chlorine pentafluoride|ClF<sub>5</sub>]],<ref name=Housecroft/>{{rp|481}} [[bromine pentafluoride|BrF<sub>5</sub>]],<ref name=Petrucci/>{{rp|413–414}} [[xenon oxytetrafluoride|XeOF<sub>4</sub>]]<ref name=Miessler/>
|-
! AX<sub>5</sub>E<sub>2</sub>
| [[Pentagonal planar molecular geometry|Pentagonal planar]]
| [[File:AX5E2-3D-balls.png|100px]]
| [[File:Pentagonal-planar-3D-balls.png|100px]]
| [[Tetramethylammonium pentafluoroxenate|{{chem|XeF|5|-}}]]<ref name=Housecroft/>{{rp|498}}
|-
! AX<sub>6</sub>E<sub>0</sub>
| [[Octahedral molecular geometry|Octahedral]]
| [[File:AX6E0-3D-balls.png|100px]]
| [[File:Octahedral-3D-balls.png|100px]]
| [[sulfur hexafluoride|SF<sub>6</sub>]]<ref name=Petrucci/>{{rp|413–414}}
|- 
! AX<sub>6</sub>E<sub>1</sub>
| [[Pentagonal pyramidal molecular geometry|Pentagonal pyramidal]]
| [[File:AX6E1-3D-balls.png|100px]]
| [[File:Pentagonal-pyramidal-3D-balls.png|100px]]
| {{chem|XeOF|5|-}},<ref name=Baran2000/> {{chem|IOF|5|2-}}<ref name=Baran2000>{{Cite journal| first1 = E. | title = Mean amplitudes of vibration of the pentagonal pyramidal {{chem|XeOF|5|-}} and {{chem|IOF|5|2-}} anions | journal = J. Fluorine Chem. | volume = 101| last1 = Baran | pages = 61–63 | year = 2000 | doi = 10.1016/S0022-1139(99)00194-3}}</ref>
|-
! AX<sub>7</sub>E<sub>0</sub>
| [[Pentagonal bipyramidal molecular geometry|Pentagonal bipyramidal]]<ref name=Miessler/>
| [[File:AX7E0-3D-balls.png|100px]]
| [[File:Pentagonal-bipyramidal-3D-balls.png|100px]]
| [[iodine heptafluoride|IF<sub>7</sub>]]<ref name=Miessler/>
|-
! AX<sub>8</sub>E<sub>0</sub>
| [[Square antiprismatic molecular geometry|Square antiprismatic]]<ref name=Miessler/>
| [[File:AX8E0-3D-balls.png|100px]]
| [[File:Square-antiprismatic-3D-balls.png|100px]]
| {{chem|IF|8|-}}, XeF<sub>8</sub><sup>2-</sup> in [[Nitrosonium octafluoroxenate(VI)|(NO)<sub>2</sub>XeF<sub>8</sub>]]
|}