# What is the geometry of IF_7?

Jul 17, 2017

This is a pentagonal bipyramidal.......with ${D}_{5 h}$ symmetry.
The interhalogen follows the normal application of $\text{VESPER}$, $\text{valence shell electron pair repulsion theory}$. The central atom, which is almost always the least electronegative atom......is iodine.
Now such a geometry is conformationally mobile, and while I have never done the experiment, in the ""^(19)F{""^1H} $\text{NMR spectrum}$ at room temperature, we would probably see the one signal due to exchange between the axial and equatorial fluorines in a mechanism similar to Berry pseudorotation observed for $P {F}_{5}$.... And should the temperature be lowered to below a certain temperature, we would see the absorption decoalesce to give 2 signals in a 2:5 ratio (in a triplet and a sextet), the one representing the axial fluorine nuclei, and the other representing the fluorine atoms in the plane.