Methylidyne-like species are implied intermediates in the Fischer–Tropsch process, the hydrogenation of CO to produce hydrocarbons.  Methylidyne entities are assumed to bond to the catalyst's surface. A hypothetical sequence is:
:MCO +  H → MCOH
:MCOH + H → MCH + HO
:MCH +  H → MCH
The MCH intermediate has a tridentate methylidine ligand. The methylene ligand (HC) is then poised couple to CO or to another methylene, thereby growing the C–C chain.