Question

The $F-Br-F$ bond angles in $Br{F}_5$ and the $Cl-P-Cl$ bond angles in $PC{l}_5$, respectively, are

• A. identical in $Br{F}_5$ but non-identical in $PC{l}_5$
• B. identical in $Br{F}_5$ and identical in $PC{l}_5$
• C. non-identical in $Br{F}_5$ but identical in $PC{l}_5$
• D. non-identical in $Br{F}_5$ and non-identical in $PC{l}_5$

Answer 1

Answer: (D)

The geometry of $Br{F}_5$ is square pyramidal.

Here, the lone pair occupies the axial position and hence axial bonds will suffer more repulsion than axial bonds.
Thus, the axial $Br—F$ bond length will be different than equitorial $Br—F$.
The geometry of $PC{l}_5$ is triangular pyramidal.

The axial bonds suffer more repulsions than equitorial bonds, so they are larger in bond length.