Talk:Transient kinetic isotope fractionation

I think the methane example in the notation section is flawed, as each H atom is adjacent to every other H atom in methane. So there can only be "adjacent" locations for two D-substitutions - there are no "non-adjacent" pairs. (The author was probably thinking of methane as a two dimensional Lewis structure rather than its actual 3-d structure.) Maybe a better example using a common molecule would be acetone, where D substitutions could happen either on the same methyl group or on different methyl groups?