Table of Three to Six Electron Domains

 

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Electron Domains Arrangement of Electron Domains General Molecular Formula1 Molecular Shape2 Examples Hybrid Orbitals3 Polar?4

2

Linear

AX2

Linear

CO2

sp

No

3

Trigonal Planar
(3 electron domains)

AX3

Trigonal planar

BF3, AlCl3

sp2

No

 

 

AX2E

Angular

SnCl2

 

Yes

4

Tetrahedral
(4 electron domains)

AX4

Tetrahedral

CH4, SiCl4

sp3

No

 

 

AX3E

Trigonal pyramidal

NH3, PCl3

 

Yes

 

 

AX2E2

Angular (Bent)

H2O, SCl2

 

Yes

5

Trigonal bipyramidal
(5 electron domains)

AX5

Trigonal bipyramidal

PCl5, AsF5

dsp3

No

 

 

AX4E

Disphenoidal
(Tetter-totter)

SF4

 

Yes

 

 

AX3E2

T-shaped

ClF3

 

Yes

 

 

AX2E3

Linear

XeF2

 

No

6

Octahedral
(6 electron domains)

AX6

Octahedral

SF6

d2sp3

No

 

 

AX5E

Square pyramidal

BrF5

 

Yes

 

 

AX4E2

Square planar

XeF4

 

No


1 For the General Molecular Formula, "A" refers to central atom, "X" refers to atoms attached to central atom, and "E" refers to unbonded electron pairs.  For example, AX2E2 is shown as the formula for water (H2O), which has two bonded hydrogen atoms ("X") and two lone (unbonded) electron pairs ("E").

2 For compounds containing 5 pairs of electrons (bonding and/or lone pairs), all lone pairs are placed in the trigonal planar electron region, never above or below the trigonal planar region.  This arrangement maximizes the  separation of lone electron pairs to their neighbors.  See the Trigonal bipyramidal(five domains) webpage for diagrams.

3 For Hybrid Orbitals, you can always know the VSEPR electron arrangement (see Arrangement of Electron Domains column).  Molecular Geometry is based on the arrangement of the bonded atoms, according to the General Molecular Formula column.

4 For molecules that contain the same attached atoms, a symmetrical molecule is not polar.  An assymetrical molecule (non-symmetrical electron domains) is polar if the individual bonds are polar.


 

 


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