## Axial and Equatorial

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

Hannah Lee 2F
Posts: 117
Joined: Thu Jul 11, 2019 12:15 am

### Axial and Equatorial

What are "axial" and "equatorial" atoms? What do we need to know about them when determining molecular shaping using VSEPR?

kpang_4H
Posts: 55
Joined: Fri Sep 20, 2019 12:17 am

### Re: Axial and Equatorial

Equatorial ones are on the x-axis or horizontal plane like an equator and axial ones are the vertical ones,

Julie Park 1G
Posts: 100
Joined: Thu Jul 25, 2019 12:15 am

### Re: Axial and Equatorial

The difference between a molecule's "energy" when the lone pairs (e-) are put on the axial or equatorial planes can help you identify the molecule's most stable structure.

A more stable structure would be one with lower "energy" (less e- repulsion)

For example, in $I{F_{4}}^{+}$, there are two possible places (orientations) where the lone pair can exist (axial or equatorial)
Here, the axial lone pair strongly repels the e- pairs in the three equatorial bonds.
Or, the equatorial lone pair can sit on the molecule’s equator (plane perpendicular to axis) where it strongly repels e- pairs in the two axial bonds (giving it a see-saw shape)

Because the lone pair only repels two e- pairs in the equatorial position (meaning that it has lower energy compared to the axial position) this orientation is more stable and preferred.