Question

In $Br{F}_3$ molecule, the lone pairs occupy equatorial positions to minimize:

• A. bond pair bond pair repulsion only
• B. lone pair lone pair repulsion and lone pair bond pair repulsion
• C. lone pairlone pair repulsion only
• D. lone pairbond pair repulsion only

Answer 1

Answer: (B)

lone pair lone pair repulsion and lone pair bond pair repulsion

In $Br{F}_3$, there are three bonding Br-F pairs and two lone pairs on B. Therefore to avoid repulsion, the lone pair occupy the two equatorial positions and the bond pairs will occupy the other three positions, it reduces the repulsion between lone pair lone-pair as well as lone pair and bond pair repulsion. It gives the following structure.