Changing shared electrons to lone pairs

[rosemarywang4i]

In VSEPR, when you change the shared electrons to lone pairs, do you remove the axial or equatorial electrons? Does this depend on the VSEPR shape?

[Elaine Pham 2E]

It depends on the VSEPR shape.
For a molecule with 5 bonded atoms and no lone pair around a central atom aka AX5 (trigonal bipyramidal), for the shape to become seesaw (AX4E), you remove the equatorial electrons first. As you keep removing the equatorial electrons from the trigonal bipyramidal shape, the shape changes to seesaw then T-shaped (AX3E2) and then linear (AX2E3) which is where the bond angle is 180.
For a molecule with 6 bonded atoms and no lone pair around a central atom aka AX6 (octahedral), you remove the axial electrons first.
You pick where electrons are removed from based on which removal (axial or equatorial electrons) will make it so that the remaining bonded atoms are the farthest away from each other as they can be.