Methyl radical
CH3•Add one electron to the cation's empty p orbital. Still flat.
- C–H 1.09 Å
- ∠HCH 120°
- planar
A radical has an unpaired electron. The methyl radical is a carbon with three C–H bonds plus one extra, lone electron. That’s seven valence electrons in total, one short of a full octet, which makes radicals very reactive. The methyl radical is a key short-lived player when methane reacts with chlorine.
The computed structure is flat (or so close to flat that it makes no difference), with H–C–H angles of 120°, just like the methyl cation. Turn on Angles & lengths and look edge-on to check. The three C–H bonds use sp²-like orbitals in the plane.
The unpaired electron goes into the p orbital standing up and down through the carbon. Turn on p orbitals to see the orbital, then π electrons: the cloud above and below the carbon is that single unpaired electron. It’s the same p orbital that is empty in the methyl cation.
So far: cation (empty p orbital, flat) → radical (one electron in the p orbital, flat). The methyl anion adds a second electron and changes shape.
Sources
3D structure, measurements and electron clouds computed with PySCF (B3LYP/def2-SVP). Computed values can differ from measured ones by a degree or so, or a few hundredths of an ångström.