Typesetting oxidation state and charge simultaneously I'm currently trying to typeset the ion $\ce{Cr2O7^{2-}}$ with oxidation numbers on. My first thought was to put the oxidation state above the atom, but according to IUPAC, the oxidation state should be in the right superscript. Combined with charge, it looks ugly and wrong:

My current ways of doing this are below


The oxidation number in right superscript. Looks weird with both numbers so close.
The oxidation number above. Looks better, but is against IUPAC.


My question therefore is: Which is the preffered way to typeset this?



Also, I would like to excuse beforehand if this should rather be in tex.stackexchange.
My personal preference in this situation would be to put square brackets around the whole ion and put the charge outside. 

$$\ce{[Cr^{VI}2O^{-II}7]^{2-}}$$ gives:
$$\ce{[Cr^{VI}2O^{-II}7]^{2-}}$$

This is sometimes done with polyatomic species anyway (particularly metal-ligand complexes) to emphasise that the charge is on the whole ion, not on any one particular atom.