[D_Alex]

Ooh, I love pedantry contests!

Let's go back to your opening comment which was something like "I thought methane was 80% hydrogen on a molar basis". Methane does not contain H2 molecules, it contains 4 atoms of hydrogen. Plus one atom of carbon, which would indeed make it 80% hydrogen on a molar basis.

If that does not convince you: note also that atomic carbon is also a very unstable, and will auto polymerize into one of its allotropes (eg. C60 - buckyballs). And yet we count carbon by the atom.