[vhpk]

Hi everyone,
I have a question regarding the geometry of the molecule.
Why does the electron pair locate at the equatorial position in AX_aE_5-a(such as: ClF₃, SF₄) molecule but at axial equation at AX_aE_6-a compound(such as: IF₅^2- ? I suppose the reason lies in the reduction in repulsion but still haven't gotten any reasonable explanation?
Thank you for the help.

[Schrödinger]

The reason is to reduce repulsion.

Hint : Think in terms of bond angles, and how it could possibly affect the interactions between electron pairs placed at the vertices of the geometrical figure under consideration.