$\require{mhchem}$
Inspired by a question on chemistry.se (now closed, because it was a cross post from Phys.SE), I observe the mhchem extension can be used here provided the question/answer contains once $\require{mhchem}$
* to render e.g., \ce{C6H12O6}
(sum formula of e.g. glucose) as $\ce{C6H12O6}$.
In the current second version, the post includes, e.g.,
$$\epsilon_n = 1.775\times10^{-20}\,\text{J}$$
the OP currently defines by $$\epsilon_n = 1.775\times10^{-20}\,\text{J}$$
. With mhchem's \pu{}
command (physical units) on Chemistry requires $$\epsilon \pu{1.775E-20 J}$$
only. Here on Physics, the resulting $$\epsilon \pu{1.775E-20 J}$$ suggests some support is missing. At present, the nested application $\ce{\pu{3 kg}}$
does not work fully either ($\ce{\pu{3 kg}}$).
Questions:
is this an issue the moderators of Physics may address to the maintainers of Stack Exchange?
alternatively, is the use of a different (perhaps more siunitx like) approach more suitable here on Physics?
* As recommended both by the author and comments on Meta Physics here. It is engaged.