Q10.41P - 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)  ${{\mathbf{ClO}}_3}^{-}$

(b)  ${{\mathbf{IF}}_4}^{-}$

(c)  ${\mathbf{SeOF}}_2$

(d)  ${{\mathbf{TeF}}_5}^{-}$

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 3 -

The shape of the molecule is pyramidal. The ideal bond angles would be $\mathbf{109}\mathbf{.}\mathbf{5}\mathbf{°}$ . The presence of lone pairs on the central chlorine atom may decrease the bond angle more than expected.

 

Step 2: IF 4 -

The shape of the molecule is square planar with a bond angle of  $\mathbf{90}\mathbf{°}$. The electron lone pairs are present on the axial position.

 

Step 3: SeOF 2

The shape of the molecule is pyramidal with an expected bond angle of  $\mathbf{109}\mathbf{.}\mathbf{5}\mathbf{°}$ . The lone pair on oxygen may decrease the bond angle from expected value.

Step 4: TeF 5 -

The structure of the molecule is square pyramidal, with bond angles of ${\mathbf{90}}^o$.