CHEM 121 glossary
Axial and equatorial positions
The two kinds of position in a trigonal bipyramid. The 2 axial positions lie on the vertical axis, each with three neighbours at 90°; the 3 equatorial positions lie in the central plane, each with only two neighbours at 90°, so lone pairs always go equatorial.
Example
In the lone pair takes an equatorial position; the two axial F atoms and two equatorial F atoms give the seesaw.