As with a lone pair, the unpaired electron influences the geometry at the radical center. Trivalent carbon-centered radicals typically have a superficial pyramidal geometry, with the methyl radical being fully trigonal planar. In comparison, trivalent sp2-hybridized carbocations are trigonal planar, while sp3-hybridized carbanions are trigonal pyramidal. While the methyl radical is planar like the former, the CF3 radical is closer to the latter. So, the trivalent radical structure with one nonbonding electron falls partway between the geometries of carbocations and carbanions. The chirality of the species is a good indicator of the geometry. A carbanion may be chiral since the pyramidal inversion is difficult. However, superficially pyramidal carbon-centered radicals are nearly planar, as they readily undergo pyramidal inversion, making such radicals achiral.