It is a metastable colourless gas, which is mainly produced in situ as a precursor to other hydrocarbons in the petroleum cracking industry.

It does not form aqueous solutions, as it reduces water to produce methanol and elemental hydrogen: The molecular geometry of the methyl radical is trigonal planar (bond angles are 120°), although the energy cost of distortion to a pyramidal geometry is small.

All other electron-neutral, non-conjugated alkyl radicals are pyramidalized to some extent, though with very small inversion barriers.

For instance, the t-butyl radical has a bond angle of 118° with a 0.7 kcal/mol (2.9 kJ/mol) barrier to pyramidal inversion.

Methyl was discovered in interstellar medium in 2000 by a team led by Helmut Feuchtgruber who detected it using the Infrared Space Observatory.