Question

Which of the following molecules has pentagonal bipyramidal shape?

• A. $P{F}_5$
• B. $S{F}_6$
• C. $Xe{F}_6$
• D. ${[Fe{(CN)}_6]}^{3-}$

Answer 1

Answer: (C)

In the formation of $Xe{F}_6$ molecule, three $5p$ electrons are promoted to $5d$ orbitals. Now, one 5s, three $5p$ and three $5d$ orbitals of Xe atom intermix together and form seven $s{p}^3{d}^3$ hybrid orbitals. One sp ${}^3{d}^3$ hybrid orbital contains one lone pair of electrons while other six are half-filled.

The expected geometry is pentagonal bipyramidal.