## VESPR bond angles

(Polar molecules, Non-polar molecules, etc.)

Hayley Hammons 1L
Posts: 26
Joined: Fri Sep 25, 2015 3:00 am

### VESPR bond angles

How do you determine the bond angle of a compound?

Shaye Busse 3B
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

### Re: VESPR bond angles

Once you determine the general 3-D layout of a compound, you can use geometry to calculate the bond angles between atoms. For example, in PCl5 the layout of the compound has one trigonal planar structure and one axial linear structure perpendicular to the former, creating a trigonal bipyramidal shape. using geometry, the angles of the Cl-P-Cl bonds in the planar piece around the central phosphorus atom would all be 120 degrees as a triangle would form. Additionally, in the axial piece, the Cl-P-Cl bond angles would be 90 degrees as it forms right angles with the atoms in the planar portion.

Spencer Cutrow 1A
Posts: 18
Joined: Fri Sep 25, 2015 3:00 am

### Re: VESPR bond angles

However, while very similar, some bond angles may change while moving down a group because each one of these atoms has slightly different properties because it is larger. For example, you have many molecules like which deviate from the traditional 109 degree angle because of different hybridization rules within each molecule. Don't mean to confuse you, but i hope this helps!

zach devereux 1C
Posts: 18
Joined: Fri Sep 25, 2015 3:00 am

### Re: VESPR bond angles

How do you know what the 3D model should look like?

Dulshan Jayasekera 3I
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

### Re: VESPR bond angles

When arranging atoms around a central atom, remember that the atoms will want to move as far away from each other as maximum separation = minimum repulsion of electrons. Therefore, if you have 2 atoms, they will move as far apart from each other creating a series of three atoms in a linear arrangement. If you have 4, it will either be a square planar (as it is with XeF4) or more commonly, tetrahedral, as it is with many carbon molecules. If you have 5 atoms, it will usually be trigonal bi-pyramidal and if you have 6, it will usually be octahedral. Hope this helps