(g) -> CH₄ (g) + CO (g), catalyzed by a methyl radical oCH₃.

*Termination:

: oCH₃ (g) + oCH₃ (g) -> C₂H₆ (g) k₄

This reaction is the only source of ethane (minor product) and it is concluded to be the main chain ending step.

Although this mechanism explains the principal products, there are others that are formed in a minor degree, such as acetone