Question

The shape of $Xe{F_6}$ is:
(1) Octahedral
(2) Trigonal bipyramidal
(3) distorted octahedral
(4) Pentagonal bipyramidal

Answer 1

Hint: First find out the hybridization of the molecule and accordingly see what the structure can be.

Formula used: Formula for finding out the hybridization of any molecule:
$H = 1/2\left[ {V + M - C + A} \right]$
Where, V=number of valence electrons;
M=monovalent atoms;
C=positive charge;
A=negative charge.

Complete step by step answer:
-Hybridization is basically a concept according to which atomic orbitals of different atoms fuse together to form new hybridized molecular orbitals. This fusing influences the molecular geometry and the bonding properties of the molecules.
So, to find out the shape of any molecule we first need to find out its hybridizations number. Each hybridization number has been assigned a suitable structure that should be formed. This gives us the shape of the molecules.
-Lets begin with finding out the hybridization of $Xe{F_6}$ :
It has V = 8 because Xe has 8 electrons in its outermost shell;
M = 6 because in this molecule all the 6 F atoms are monovalent in nature;
C and A = 0 because the molecule is neutral.
Using formula: $H = 1/2\left[ {V + M - C + A} \right]$
=1/2 [8+6+0+0]
=7
Since the hybridization number is 7, the hybridization of the molecule is $s{p^3}{d^3}$. We can also say that Xe has 8 electrons in its outermost shell of which 6 form bonds with F atoms leaving behind 1 lone pair. Hence the molecule of $Xe{F_6}$ has 6 bond pairs and 1 lone pair of electrons.
Since, $Xe{F_6}$ has $s{p^3}{d^3}$ hybridization, its geometry will be distorted octahedral.
So, the correct option is: (3) distorted octahedral.

Note: In such questions mistakes are made only while putting the values of V, M, C and A in hybridization formula. So, be very careful while putting these values.