Q10.40P - Chemistry: Molecular Nature Of Matter And Change

Question

Determine the shape, ideal bond angle(s), and the direction of any deviation from those angles for each of the following:

(a)  ${\mathbf{ClO}}_2^{-}$

(b)  ${\mathbf{PCl}}_5$

(c)  ${\mathbf{SeF}}_4$

(d)  ${\mathbf{KrF}}_4$

Step-by-Step Solution

Answer

The shapes and bond angles of molecules can be determined from the VSEPR theory. The deviations arise mainly due to lone pair-lone pair repulsions.

Step 1: ClO 2 -

The shape of the molecule is bent, with an expected bond angle of  $\mathbf{120}\mathbf{°}$.  The presence of lone pair decreases the bond angle than the expected

Step 2: PCl 5

PCl₅ has a structure of trigonal bipyramidal. The axial bonds have a bond angle of $\mathbf{180}\mathbf{°}$. The equatorial bonds have a bond angle of  $\mathbf{120}\mathbf{°}$.

Step 3: SeF 4

The selenium atom is sp³d hybridized with a see saw shape. The bond angles are  $\mathbf{120}\mathbf{°}$ and $\mathbf{90}\mathbf{°}$ ^. However, the bond angle may decrease due presence of lone pairs around the central atom.

Step 4: KrF 4

The shape of the molecule is linear with bond angle of  $\mathbf{180}\mathbf{°}$ . The lone pairs occupy the equatorial positions of the trigonal bipyramidal geometry.