When is the oxidation state of metal indicated in the name of a comoound?

The oxidation state of a metal is indicated in the name of a compound when the metal can exhibit more than one oxidation state. This is commonly seen in transition metals and some post-transition metals, where Roman numerals are used to specify the oxidation state. For example, in iron(III) chloride (FeCl₃), the Roman numeral III indicates that iron has an oxidation state of +3. In contrast, if a metal has only one oxidation state, it is not typically specified in the compound's name.