Why is phenyl carbanion aromatic? In phenyl carbanion, one carbon atom has a lone pair on it:

This answer claims that the anion is aromatic, because &quot;the lone pair on the benzene is in the plane of the ring and hence orthogonal to the conjugated $\pi$-system so that it cannot interact with it.&quot;
Why is the lone pair perpendicular to the plane of the molecule? It seems clear to me that the carbon in question has three $\mathrm{sp^2}$ orbitals, perpendicular to which is a pure $\mathrm{p}$-orbital containing two electrons. Assigning one extra electron (i.e., a negative charge) to an uncharged carbon in a benzene ring shouldn't rotate its $\mathrm{p}$-orbital by $90^\circ$.
The $\mathrm{p}$-orbitals in carbon are, of course, always perpendicular to each other. The $\mathrm{p}$-orbital containing the lone pair should, therefore, be perpendicular to the hybridized orbitals.
The lone pair of electrons will be in a $\mathrm{sp^2}$ hybridized orbital and not in  a pure p-orbital. Thus, it wil be in the same plane as the molecule. Only the lone pairs which are in an orbital perpendicular to the molecular plane can take part in resonance, so those $\mathrm{sp^2}$ electrons will not be counted in Hückel's rule.