Question

Why all $P - F$ bonds in $PF_5$ are not equivalent ?

• A. $PF_5$ has $sp^3d$ hybridisation, out of five $P - F$ bonds three are equatorial which have different lengths
• B. $PF_5$ has $sp^3$ hybridisation, out of five $P - F$ bonds two are equatorial which have different lengths
• C. Out of five $P - F$ bonds two are axial and three equatorial. All five bonds have different bond lengths
• D. $PF_5$ is made up of two types of bonds namely covalent and coordinate, hence are not equivalent

Answer 1

Answer: (A)

Structure of $PF _{5}$
$PF _{5}$ has three axial bonds and two equitorial bonds and has $sp ^{3} d$ hybridisation $PCl _{5}$ has trigonal bipyramidal structure .
Due to this two $Cl$ atoms lie along axial line and other three $Cl$ atoms lie along the equatorial plane.
Hence $Cl$ atoms which lie along axis have different bond length than that of $Cl$ atoms lying on equatorial plane.