Count the electron pairs around iodine in $IF_7$

• Iodine is the central atom.
• It is bonded to $7$ fluorine atoms.
• Thus, there are $7$ bond pairs around iodine and no lone pair on the central atom.

Apply VSEPR theory

For a central atom with steric number $7$ (i.e. $7$ regions of electron density), the arrangement that minimizes repulsion is: $\text{Pentagonal bipyramidal}$

Match with the given options

• A: trigonal bipyramid $\rightarrow$ steric number $5$
• B: octahedral $\rightarrow$ steric number $6$
• C: pentagonal bipyramid $\rightarrow$ steric number $7$
• D: square pyramid $\rightarrow$ derived from octahedral with one lone pair

Therefore, the correct structure of $IF_7$ is: $\boxed{\text{Pentagonal bipyramid}}$

Compare with stored answer

• Derived answer: C
• Stored correct answer: C

Both match.