Can you write oxidation states with negative Roman numerals?

As I understand, Roman numerals are used for oxidation states, whereas Arabic numerals are used for the charge of full ions, with some ambiguity allowed when a metal centre is all but ionised, such as in hexaaqua compounds.


But I have never seen a Roman numeral with a negative sign in front of it. Would I write the oxidation state of sulphur in hydrogen sulphide (H$\_2$S) as (-II)?




According to IUPAC guidelines, roman numerals are used to denote oxidation states when used in the name of a compound. This is used when the cationic group can have varying oxidation states. For example, $\ce{FeSO4}$ is written as iron (II) sulphate, and $\ce{Fe2(SO4)3}$ is written as iron (III) sulphate. Although anionic groups can also have variable oxidation states, we omit mentioning the oxidation state in the name of the compound. Instead, we use standard prefixes to identify the oxidation states. For example, potassium oxide ($\ce{K2O}$), potassium peroxide ($\ce{K2O2}$), and potassium superoxide ($\ce{KO2}$) have different oxidation states for oxygen: -2, -1, and -1/2 respectively. But instead of mentioning this explicitly, we denote these with different standard names.


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Converting my comment into answer upon OP's request.




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Basically the other answer is correct. Metals tends to hold positive charge and they achieve multiple oxidation state. So, in order to differentiate them, we use roman numerical in their names to avoid confusion and simultaneously providing the O.S. of metal which is always a useful information. For e.g iron(II) oxide and iron(III) oxide In few occasion, metal can achieve negative when the entity holds a negative charge, thus becoming an anion. For anions, we use specific suffixes for different oxidation state. So, in this case we don't need roman numbers. For e.g. Disodium tetracarbonylferrate. We don't need to mention **(-II)** since it is redundant and in theory, [roman numerals doesn't exist for 0 and negative numbers.](https://romannumerals.guide/how-roman-numerals-work) But some publication([example](https://baranlab.org/wp-content/uploads/2018/12/Metals-in-Negative-Oxidations-States-Final-Presentation.pdf)) and textbooks still adopts the writing style for convenience sake(at least in formulae).


Here is a good article on this topic:<https://pubs.acs.org/doi/pdf/10.1021/ed2001347>


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