Question

In which of the following species, the depicted $C$ is $s{p}^2$ hybridized?

• A. $p,q$
• B. $p,qandr$
• C. $p,q,sandt$
• D. $q,sandt$

Answer 1

The correct option is D $q,sandt$

There are two important effects that contribute to the pyramidal shape and $s{p}^3$ hybridization of the $C{F}_3$ radical:

1) Electron-electron repulsion;

2) Hyperconjugation.

The unpaired electron on carbon repels more with the lone pairs on the fluorine atoms in planar geometry (predicted by $s{p}^2$ hybridization) than in pyramidal geometry ($s{p}^3$ hybridization):

There is also a hyperconjugation-type stabilization in pyramidal geometry, between the orbitals that contains the lone pair and the C-F antibonding orbital. In planar geometry the orbitals are perpendicular and no overlap occurs.