How are oxidation states of transition metals indicate in the names of metal compounds?

Preferably in modern nomenclature, by capital "Roman numerals" within parentheses immediately following the name of a transition metal element cation in a chemical compound. For transition metal elements that have only two common cationic oxidation states, the oxidation states can alternatively be indicated by the suffix "ic" for the more positive oxidation state and "ous" for the less positive ones. Examples are "ferric" for "iron (III)" and "ferrous" for "iron (II)".

If the transition metal is in an anion, the most common indication is with suffixes and prefixes, but the appended oxidation state in parentheses can also be used. Details may be different for different transition metals and should be sought in an authoritative reference source.