"has not been generally used as a feedstock in simple thermal cracking... because the decomposition temperature is too high and yield of useful products too low. Nevertheless... pyrolysis of methane has been used for the production of acetylene and ... Diamonds can be formed... under suitable conditions... [E]arly stages of...decomposition are... well understood... but... details of later stages are not... clear... All oxidation reactions, including oxidative pyrolysis, have been excluded."